ORCID Profile
0000-0003-3626-5361
Current Organisations
University of Derby
,
Ghana Institute of Management and Public Administration
,
The Hong Kong Polytechnic University
,
Griffith University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Microelectromechanical Systems (MEMS) | Mechanical Engineering | Microtechnology | Chemical Engineering Design | Sensor Technology (Chemical aspects) | Chemical Engineering | Nanoscale Characterisation | Fluid mechanics and thermal engineering | Atomic, Molecular, Nuclear, Particle and Plasma Physics | Materials engineering | Condensed Matter Physics | Microelectronics and Integrated Circuits | Immunological and Bioassay Methods | Chemical Characterisation of Materials | Artificial Intelligence and Image Processing | Polymers and plastics | Composite and hybrid materials | Agricultural Biotechnology | Microfluidics and nanofluidics | Manufacturing Engineering | Nanotechnology | Materials Engineering | Petroleum and Reservoir Engineering | Composite and Hybrid Materials | Lasers and Quantum Electronics | Analytical Chemistry | Physical properties of materials | Interdisciplinary Engineering not elsewhere classified | Pattern Recognition and Data Mining | Microelectromechanical systems (MEMS) | Computer Vision | Nanomaterials | Chemical Engineering not elsewhere classified | Heat and Mass Transfer Operations | Agricultural Biotechnology Diagnostics (incl. Biosensors) | Surfaces and Structural Properties of Condensed Matter | Soft Condensed Matter | Plasma Physics; Fusion Plasmas; Electrical Discharges | Condensed Matter Characterisation Technique Development | Atomic and Molecular Physics
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in Technology | Scientific Instruments | Expanding Knowledge in Engineering | Diagnostic Methods | Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Physical Sciences | Control of Pests, Diseases and Exotic Species in Fresh, Ground and Surface Water Environments | Plant Production and Plant Primary Products not elsewhere classified | Sugar | Geothermal Energy Extraction | Oil and Gas Extraction | Energy Transmission and Distribution (excl. Hydrogen) | Machined Metal Products | Industrial Machinery and Equipment | Management of Solid Waste from Manufacturing Activities | Mining Machinery and Equipment | Integrated Circuits and Devices | Oil and Gas Exploration | Solar-Photovoltaic Energy | Fisheries - Aquaculture not elsewhere classified | Expanding Knowledge in the Environmental Sciences | Expanding Knowledge in the Agricultural and Veterinary Sciences | Expanding Knowledge in the Biological Sciences |
Related Links
Publications
Mesoporous gold–silver alloy films towards amplification-free ultra-sensitive microRNA detection
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TB02003F
Abstract: The fabrication of a bimetallic mesoporous Au–Ag biosensor for achieving attomolar sensitive detection of magnetically purified target miRNA without any lification or enzymatic process is reported.
POCS-based blocking artifacts suppression using a smoothness constraint set with explicit region modeling
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 06-2005
Orientation dependence of the pseudo-Hall effect in p-type 3C–SiC four-terminal devices under mechanical stress
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA10144A
Abstract: This study reports on the orientation dependence and shear piezoresistive coefficients of the pseudo-Hall effect in p-type single crystalline 3C–SiC.
Gold-loaded nanoporous superparamagnetic nanocubes for catalytic signal amplification in detecting miRNA
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7CC04789D
Abstract: A nonenzymatic, lification-free, and sensitive method for microRNA detection is reported using Au@NPFe 2 O 3 NC nanocubes.
Demonstration of Electron/Hole Injections in the Gate of $p$-GaN/AlGaN/GaN Power Transistors and Their Effect on Device Dynamic Performance
Publisher: IEEE
Date: 05-2019
Design and optimization of an ultrasonic flexural plate wave micropump using numerical simulation
Publisher: Elsevier BV
Date: 11-1999
An automated on-demand liquid marble generator based on electrohydrodynamic pulling
Publisher: AIP Publishing
Date: 05-2019
DOI: 10.1063/1.5094522
Abstract: Liquid marble is a recently emerging digital microfluidic platform with a wide range of applications. Conventional liquid marbles are synthesized by coating liquid droplets with a thin layer of hydrophobic powder. Existing and emerging applications of liquid marbles require a contamination-free synthesis of liquid marbles with a high degree of reproducibility of their volume. Despite this requirement, the synthesis of liquid marbles has been still carried out manually. Manual production of liquid marbles leads to inconsistent volume and the possibility of contamination. The synthesis of liquid marbles with submicroliter volume is difficult to achieve and prone to large errors. This paper discusses the design and development of the first automated on-demand liquid marble generator with submicroliter capability. The device utilizes electrohydrodynamic pulling of liquid droplets on to a hydrophobic powder bed and subsequently coats them with the hydrophobic powder to synthesize liquid marbles of a desired volume.
Reciprocating thermocapillary plug motion in an externally heated capillary
Publisher: Springer Science and Business Media LLC
Date: 30-06-2007
Effect of 3C-SiC Layer Thickness on Lateral Photovoltaic Effect in 3C-SiC/Si Heterojunction
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 02-2023
A simple method for the formation of water-in-oil-in-water (W/O/W) double emulsions
Publisher: Springer Science and Business Media LLC
Date: 2017
Colorimetric Immunological Paper-based Assay for Exosome Detection
Publisher: Research Square Platform LLC
Date: 06-10-2021
DOI: 10.21203/RS.3.RS-956090/V1
Abstract: This paper reports the development of colorimetric immunological paper-based assay for exosome detection. The paper-based device was fabricated with lamination technique for easy handling and create hydrophilic/hydrophobic region for analytical paper-based devices. Exosome-specific antibody was coated onto the paper-based devices as a biosensing platform to detect exosome s le from the cell culture media. This assay employed a colorimetric reaction which is followed by reaction between horseradish peroxidase (HRP) and 3,3’,5,5’-tetramethylbenzidine substrate (TMB). The colorimetric readout was qualitatively evaluated by naked eyes and was quantitatively assessed by image processing software. The result indicated that this assay faces many challenges. First, the exosome concentration may be inadequate to reach detectable range. Second, high background signal due to non-specific binding on the platform results in lack of sensitivity for exosome detection. Therefore, modification on the paper should promote protein binding for specific target and prevent non-specific binding to reduce the high background signal.
Biconcave micro-optofluidic lens with low-refractive-index liquids
Publisher: Optica Publishing Group
Date: 19-11-2009
DOI: 10.1364/OL.34.003622
Thermal fluid interaction in a periodically heated capillary
Publisher: ASMEDC
Date: 2007
DOI: 10.1115/HT2007-32062
Abstract: This paper reports an experimental study on reciprocating thermocapillary motion of a liquid plug in an externally heated glass capillary. The results were qualitatively compared with that from an analytical modeling. In the experiments, a liquid plug in a glass capillary was positioned between two heaters which were activated alternatively. The liquid plug was driven by the surface tension difference generated by the temperature gradients. The periodic temperature gradients generated by the two heaters made the liquid plug to move back and fort. This method has a potential in manipulating not only the plug motion but also the flow field inside the plug. The position of the plugs was captured and evaluated using a CCD camera. The plug position and maximum traveling distance were measured under various switching frequencies, and the results were recorded as time series for the dynamic analysis. The temperature variation between the heaters depended on the heating process, also depended on the liquid plug motions. An infra thermal camera was used to observe and record the capillary surface temperature when the liquid plug oscillated. A simple model was established for the liquid plug oscillation in the capillary under the periodical heating. The measured liquid plug motion and the temperature variations were compared with predicted results from the model.
Low-pressure, high-temperature thermal bonding of polymeric microfluidic devices and their applications for electrophoretic separation
Publisher: IOP Publishing
Date: 12-07-2006
Long Path-Length Axial Absorption Detection in Photonic Crystal Fiber
Publisher: American Chemical Society (ACS)
Date: 07-05-2008
DOI: 10.1021/AC800417N
Abstract: In this paper, we present a long path-length axial absorption detection method in photonic crystal fibers (PCFs). A PCF, also called a holey fiber or microstructured fiber, is an optical fiber which consists of a periodic array of very tiny and closely spaced air holes on the scale of 1 microm running through the whole length of the fiber. Here, a PCF with porous microstructures was used as a s le container for absorption detection. Light was guided by total internal reflection and propagated axially in the air holes of PCFs that were filled with the solution of the absorbing species by vacuum pumping. Excellent linearity was obtained for different s le concentrations, and high sensitivity was achieved due to the long optical path length. In addition, as the dimension of the PCF is small, the s le volume is greatly reduced. Moreover, due to its robustness, the PCF can be coiled up to keep the footprint small, making it suitable for microchip absorption detection. It can be widely used for both off-chip and on-chip detection of absorbing species, such as ions, alkaloids, and biomolecules.
Faster and improved microchip electrophoresis using a capillary bundle
Publisher: Wiley
Date: 12-2007
Abstract: Joule heating generated in CE microchips is known to affect temperature gradient, electrophoretic mobility, diffusion of analytes, and ultimately the efficiency and reproducibility of the separation. One way of reducing the effect of Joule heating is to decrease the cross-section area of microchannels. Currently, due to the limit of fabrication technique and detection apparatus, the typical dimensions of CE microchannels are in the range of 50-200 microm. In this paper, we propose a novel approach of performing microchip CE in a bundle of extremely narrow channels by using photonic crystal fiber (PCF) as separation column. The PCF was simply encapsulated in a poly(methyl methacrylate) (PMMA) microchannel right after a T-shaped injector. CE was simultaneously but independently carried out in 54 narrow capillaries, each capillary with diameter of 3.7 microm. The capillary bundle could sustain high electric field strength up to 1000 V/cm due to efficient heat dissipation, thus faster and enhanced separation was attained.
Electrochemical Detection of FAM134B Mutations in Oesophageal Cancer Based on DNA-Gold Affinity Interactions
Publisher: Wiley
Date: 09-02-2017
Biological Functions and Current Advances in Isolation and Detection Strategies for Exosome Nanovesicles
Publisher: Wiley
Date: 28-12-2018
Abstract: Exosomes are nanoscale (≈30-150 nm) extracellular vesicles of endocytic origin that are shed by most types of cells and circulate in bodily fluids. Exosomes carry a specific composition of proteins, lipids, RNA, and DNA and can work as cargo to transfer this information to recipient cells. Recent studies on exosomes have shown that they play an important role in various biological processes, such as intercellular signaling, coagulation, inflammation, and cellular homeostasis. These functional roles are attributed to their ability to transfer RNA, proteins, enzymes, and lipids, thereby affecting the physiological and pathological conditions in various diseases, including cancer and neurodegenerative, infectious, and autoimmune diseases (e.g., cancer initiation, progression, and metastasis). Due to these unique characteristics, exosomes are considered promising biomarkers for the diagnosis and prognosis of various diseases via noninvasive or minimally invasive procedures. Over the last decade, a plethora of methodologies have been developed for analyzing disease-specific exosomes using optical and nonoptical tools. Here, the major biological functions, significance, and potential role of exosomes as biomarkers and therapeutics are discussed. Furthermore, an overview of the most commonly used techniques for exosome analysis, highlighting the major technical challenges and limitations of existing techniques, is presented.
Brain symmetry plane detection based on fractal analysis
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.COMPMEDIMAG.2013.06.001
Abstract: In neuroimage analysis, the automatic identification of symmetry plane has various applications. Despite the considerable amount of research, this remains an open problem. Most of the existing work based on image intensity is either sensitive to strong noise or not applicable to different imaging modalities. This paper presents a novel approach for identifying symmetry plane in three-dimensional brain magnetic resonance (MR) images based on the concepts of fractal dimension and lacunarity analysis which characterizes the complexity and homogeneity of an object. Experimental results, evaluation, and comparison with two other state-of-the-art techniques show the accuracy and the robustness of our method.
Interface control of pressure-driven two-fluid flow in microchannels using electroosmosis
Publisher: IOP Publishing
Date: 08-11-2005
Dispersive phase microscopy incorporated with droplet-based microfluidics for biofactory-on-a-chip
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3LC00127J
Abstract: This work presents how the merging of droplet-based microfluidics and dispersive phase microscopy can expedite the evolution of cell towards desired phenotypes. The proposed system holds the potential for biofactory-on-chip applications.
Particle Transport in Microchannels
Publisher: Informa UK Limited
Date: 05-2007
Capillary Filling in Nanochannels—Modeling, Fabrication, and Experiments
Publisher: Informa UK Limited
Date: 06-2011
Lossless image compression using binary wavelet transform
Publisher: Institution of Engineering and Technology (IET)
Date: 2007
Eccentricity Effect of Micropatterned Surface on Contact Angle
Publisher: American Chemical Society (ACS)
Date: 02-03-2012
DOI: 10.1021/LA300416X
Abstract: This article experimentally shows that the wetting property of a micropatterned surface is a function of the center-to-center offset distance between successive pillars in a column, referred to here as eccentricity. Studies were conducted on square micropatterns which were fabricated on a silicon wafer with pillar eccentricity ranging from 0 to 6 μm for two different pillar diameters and spacing. Measurement results of the static as well as the dynamic contact angles on these surfaces revealed that the contact angle decreases with increasing eccentricity and increasing relative spacing between the pillars. Furthermore, quantification of the contact angle hysteresis (CAH) shows that, for the case of lower pillar spacing, CAH could increase up to 41%, whereas for the case of higher pillar spacing, this increment was up to 35%, both corresponding to the maximum eccentricity of 6 μm. In general, the maximum obtainable hydrophobicity corresponds to micropillars with zero eccentricity. As the pillar relative spacing decreases, the effect of eccentricity on hydrophobicity becomes more pronounced. The dependence of the wettability conditions of the micropatterned surface on the pillar eccentricity is attributed to the contact line deformation resulting from the changed orientation of the pillars. This finding provides additional insights in design and fabrication of efficient micropatterned surfaces with controlled wetting properties.
Size-tuneable isolation of cancer cells using stretchable inertial microfluidics
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1LC00082A
Abstract: We present a stretchable inertial microfluidic device for tuneable separation of spiked cancer cells from blood s le.
Characterization of the piezoresistance in highly doped p-type 3C-SiC at cryogenic temperatures
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8RA05797D
Abstract: The piezoresistance in crystalline 3C-SiC epitaxially grown on Si was investigated at low temperatures down to 150 K. The large gauge factor in 3C-SiC indicates its feasibility for sensing applications in cryogenic environments.
Flexible and Wearable Flow Sensor Using Spinnable Carbon Nanotube Nanofilm for Respiration Monitoring
Publisher: IEEE
Date: 2020
Combinational concentration gradient confinement through stagnation flow
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5LC01137J
Abstract: A concentration gradient device generates stagnation flows which confine combinational concentration gradients within velocity wells, thereby suppressing shear stress effects.
Hydrodynamically mediated breakup of droplets in microchannels
Publisher: AIP Publishing
Date: 31-01-2011
DOI: 10.1063/1.3552680
Abstract: A flow focusing junction is integrated into a microchannel to break up droplets into a controllable number and size of daughter droplets. High speed images of the breakup at the flow focusing junction show that the breakup depends on the interplay between interfacial tension, shear force on the interface, and the confinement of the microchannel. Phase diagrams of the splitting performance show that the breakup is controllable by varying the flow rate of the continuous phase or by varying the size of the mother droplet.
Special issue on magnetic-based microfluidics
Publisher: Springer Science and Business Media LLC
Date: 12-09-2012
Advances in drug delivery to atherosclerosis: Investigating the efficiency of different nanomaterials employed for different type of drugs
Publisher: Elsevier BV
Date: 10-2023
Integrated, Transparent Silicon Carbide Electronics and Sensors for Radio Frequency Biomedical Therapy
Publisher: American Chemical Society (ACS)
Date: 11-07-2022
Two-Fluid Electroosmotic Flow in Microchannels
Publisher: ASMEDC
Date: 2008
Abstract: This paper presents theoretical and experimental investigations of the pressure-driven two-liquid flow in microchannels with the electroosmosis effect. For a fully developed, steady state, laminar flow of two liquids combined the pressure gradient, electroosmosis and surface charges at the liquid-liquid interface, we have derived analytical solutions that relate the velocity profiles and flow rates to the liquid holdup, the aspect ratio of the microchannel, the viscosity ratio of the two liquids and the externally applied electric field. It was shown that adjusting the externally applied electric field could control the fluid interface position precisely. The prediction from the proposed model compares very well with measured data.
Membraneless hydrogen peroxide micro semi-fuel cell for portable applications
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4RA00874J
Abstract: A one-compartment hydrogen peroxide semi-fuel cell was fabricated using a metallic anode (Mg or Al) and Prussian blue as the cathode to improve the power density of the device.
Electrophoretic Motion of Particles in a Microsystem
Publisher: ASMEDC
Date: 2019
Abstract: Electrophoresis is the motion of a charged particle relative to the surrounding liquid due to an imposed external electric field1. Its applications include but are not limited to characterization and manipulation of organic and inorganic particles. In particular, electrophoresis has been applied to a variety of analytical separation problems involving nucleic acids, proteins and drugs. For electrophoresis on various Lab-on-a-chip platforms, the particles are of sizes comparable to the microchannel in which they flow. As such, particle-particle and particle-wall interactions are no longer negligible. Therefore, the electric field, the flow field and the particles motion are strongly coupled together. Numerical models based on a moving-grid method2 have been employed to investigate the related phenomena. Mesh regeneration as the particles move is an extra computational complication. To circumvent the complexity of mesh regeneration, a level-set based fixed-grid method3 is presented for electrophoretic motion of particles in this article. The particles are assumed to be a highly viscous liquid constraint to move with rigid body motion. A distance function is employed to represent the liquid-particle interfaces. The electric field, the flow field and the particles motion are governed respectively by the Poisson, the Navier-Stokes and the Euler-Newton equations. The effect of the electric field on the particle motion is accounted for by incorporating slip boundary conditions on the particles surfaces. The nonlinear governing equations are discretized and solved using a finite volume method4. The model is used to investigate electrophoretic motion of non-conducting circular and elliptical particles in a microsystem. Figure 1 shows the electrophoretic motion of a single circular particle in a microchannel. The induced electroosmotic flow is from the left to the right. The thick circles are the particle at t = 0. The direction of the particle movement is indicated by the arrows. The motions of the particle if neutral, positively or negatively charged are obviously different. Basically, a positively charged particle move faster than the main flow. However, a negatively charged particle flows slower. When the particle is highly charged negative, it can even flow against the streamwise direction toward upstream (+V) as in Fig. 1c. This suggests that there would be a situation where the particle can be kept static. Figure 2 shows the electrophoretic motion of multiple particles. The initial locations of the particles are shown in Fig. 2a. In the case of charged particles, particle 1, 2 and 3 are respectively negatively, neutral and positively charged. Particle 1 which is elliptical undergoes obvious rotational motion when charged (Fig. 2c). The case of the neutral particles (Fig. 2b) is included for comparison.
Calcium phosphate stability on melt electrowritten PCL scaffolds
Publisher: Elsevier BV
Date: 03-2020
Characterization of Temperature Dependence of Interfacial Tension and Viscosity of Nanofluid
Publisher: ASMEDC
Date: 2008
Abstract: Investigations on temperature dependence of surface tension, interfacial tension and viscosity a nanofluid are reported in this paper. Experimental results show that nanofluid having TiO2 nanoparticles (15 nm) in deionized water exhibit substantially smaller surface tension and oil-based interfacial tension than those of the base fluid (i.e. deionized water). These surface and interfacial tensions of this nanofluid were found to decrease almost linearly with increasing temperature. The Brownian motion of nanoparticles in base fluid was identified as a possible mechanism for reduced surface and interfacial tensions of nanofluid. The measured effective viscosity of nanofluid was found to be insignificantly higher than that of base fluid and it also decreases with increasing fluid temperature.
Evaporation dynamics of liquid marbles at elevated temperatures
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8RA02265H
Abstract: We investigate the evaporation behaviour of a group of liquid marbles at elevated temperature under various conditions.
DNA methylation detection: recent developments in bisulfite free electrochemical and optical approaches
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8AN01348A
Abstract: The recent development of optical and electrochemical biosensors for bisulfite treatment free DNA methylation detection methods have been reviewed. The major challenges associated with the bisulfite treatment in DNA methylation detection and their potential solutions are also discussed.
Experimental and computational analysis of droplet formation in a high-performance flow-focusing geometry
Publisher: Elsevier BV
Date: 07-2007
Highly-doped SiC resonator with ultra-large tuning frequency range by Joule heating effect
Publisher: Elsevier BV
Date: 09-2020
A tunable optofluidic lens based on combined effect of hydrodynamics and electroosmosis
Publisher: Springer Science and Business Media LLC
Date: 21-11-2010
Prediction of Necrotic Core and Hypoxic Zone of Multicellular Spheroids in a Microbioreactor with a U-Shaped Barrier
Publisher: MDPI AG
Date: 25-02-2018
DOI: 10.3390/MI9030094
Porous scaffolds for bone regeneration
Publisher: Elsevier BV
Date: 03-2020
Investigation of liquid marble shell using X‐ray: shell thickness and effective surface tension
Publisher: Wiley
Date: 12-2022
Abstract: Liquid marble is a non‐wetting droplet encapsulated by micro‐ or nano‐sized hydrophobic particles. Recently, liquid marble has been emerging as a tool for digital microfluidics. Thus, a detailed understanding of the fundamentals of liquid marble is essential. The shell of a liquid marble has an opaque and fuzzy appearance which hinders in‐depth investigation using conventional optical microscopy. We used X‐ray computerized microtomography (CMT) to generate an image with a visible interface between the core liquid and the shell to overcome this problem. The interface facilitates accurate measurement of the shell thickness and the effective surface tension. This work investigates the effect of liquid marble preparation methods and liquid marble volumes on shell thickness and effective surface tension. We found that increasing the revolution speed during liquid marble preparation increases shell thickness. A liquid marble shell has a uniform packing when the revolution speed is 200–300 rpm. We also found that the effective surface tension of liquid marbles decreases with increasing volume. This could be due to a stronger effect of gravitational force for a large liquid marble. The findings from this work could provide a new insight into the characterization of liquid marble and open up a new direction of fundamental research of liquid marble shell.
Micromixers—a review
Publisher: IOP Publishing
Date: 09-12-2004
Droplet manipulation in a microfluidic chamber with acoustic radiation pressure and acoustic streaming
Publisher: Royal Society of Chemistry (RSC)
Date: 04-09-2014
DOI: 10.1039/C4SM01453G
Abstract: The present paper reports a novel manipulation method for droplets using acoustic radiation pressure and acoustic streaming. In an acoustic field, droplets deform, oscillate and move in a wide range of applied frequencies. The behavior of a droplet depends on the droplet size, acoustic field and interfacial tension between the two phases. The acoustic field is controlled by the voltage and frequency of the piezoelectric actuator. The results demonstrate a method for low-frequency acoustic actuation of droplets in a microfluidic environment.
Efficient mixing of viscoelastic fluids in a microchannel at low Reynolds number
Publisher: Springer Science and Business Media LLC
Date: 28-07-2007
Piezotronic effect in a normally off p-GaN/AlGaN/GaN HEMT toward highly sensitive pressure sensor
Publisher: AIP Publishing
Date: 14-06-2021
DOI: 10.1063/5.0053701
Abstract: We report the effect of stress or strain on the electronic characteristics of a normally off AlGaN/GaN high electron mobility transistor (HEMT) and demonstrate its role as a highly sensitive pressure sensor. We observe that the HEMT drain current exhibits a linear change of 2.5%/bar upon the application of pressure, which is translated to a strain sensitivity of 1250 ppm−1. This is the highest strain sensitivity ever reported on HEMTs and many other conventional strain sensing configurations. The relative change of drain current is largest when the gate bias is near-threshold and drain bias is slightly larger than the saturation bias. The electron sheet density and mobility changes in the AlGaN/GaN heterointerface under the applied pressure or mechanical strain are explained qualitatively. The spontaneous and piezoelectric-polarization-induced surface and interface charges in the AlGaN/GaN heterojunction can be used to develop very sensitive and robust pressure sensors. The results demonstrate a considerable potential of normally off AlGaN/GaN HEMTs for highly sensitive and reliable mechanical sensing applications with low energy consumption.
The Piezoresistive Effect of SiC for MEMS Sensors at High Temperatures: A Review
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2015
Robust Free-Standing Nano-Thin SiC Membranes Enable Direct Photolithography for MEMS Sensing Applications
Publisher: Wiley
Date: 15-12-2018
A high-performance polydimethylsiloxane electrospun membrane for cell culture in lab-on-a-chip
Publisher: AIP Publishing
Date: 03-2018
DOI: 10.1063/1.5021002
Abstract: Thin porous membranes are important components in a microfluidic device, serving as separators, filters, and scaffolds for cell culture. However, the fabrication and the integration of these membranes possess many challenges, which restrict their widespread applications. This paper reports a facile technique to fabricate robust membrane-embedded microfluidic devices. We integrated an electrospun membrane into a polydimethylsiloxane (PDMS) device using the simple plasma-activated bonding technique. To increase the flexibility of the membrane and to address the leakage problem, the electrospun membrane was fabricated with the highest weight ratio of PDMS to polymethylmethacrylate (i.e., 6:1 w/w). The membrane-integrated microfluidic device could withstand a flow rate of up to 50 μl/min. As a proof of concept, we demonstrated that such a compartmentalized microfluidic platform could be successfully used for cell culture with the capability of providing a more realistic in vivo-like condition. Human lung cancer epithelial cells (A549) were seeded on the membrane from the top microchannel, while the continuous flow of the culture medium through the bottom microchannel provided a shear-free cell culture condition. The tortuous micro-/nanofibers of the membrane immobilized the cells within the hydrophobic micropores and with no need of extracellular matrix for cell adhesion and cell growth. The hydrophobic surface conditions of the membrane were suitable for anchorage-independent cell types. To further extend the application of the device, we qualitatively showed that rinsing the membrane with ethanol prior to cell seeding could temporarily render the membrane hydrophilic and the platform could also be used for anchorage-dependent cells. Due to the three-dimensional (3D) topography of the membranes, three different configurations were observed, including in idual single cells, monolayer cells, and 3D cell clusters. This cost-effective and robust compartmentalized microfluidic device may open up new avenues in translational medicine and pharmacodynamics research.
Noninvasive refilling of liquid marbles with water for microfluidic applications
Publisher: AIP Publishing
Date: 07-02-2022
DOI: 10.1063/5.0074887
Abstract: Liquid marbles, liquid droplets coated with hydrophobic powder, have been emerging as a useful microfluidic platform. The ease of their synthesis and manipulation allows liquid marbles to serve as a robust microreactor. However, liquid marbles suffer the unavoidable problem of evaporation. Exposed to an environment with relatively low humidity, the liquid marble buckles and collapses due to evaporation. A suitably noninvasive technique to refill the liquid marble with water may open better opportunities for liquid marbles in microfluidics. To date, there has been no report on noninvasive methods for refilling the deflated liquid marble after the evaporation and subsequent buckling. This paper reports the noninvasive automatic refilling of liquid marbles using the concept of vapor transfer through porous media and subsequent condensation.
Single-Crystalline 3C-SiC anodically Bonded onto Glass: An Excellent Platform for High-Temperature Electronics and Bioapplications
Publisher: American Chemical Society (ACS)
Date: 15-08-2017
Abstract: Single-crystal cubic silicon carbide has attracted great attention for MEMS and electronic devices. However, current leakage at the SiC/Si junction at high temperatures and visible-light absorption of the Si substrate are main obstacles hindering the use of the platform in a broad range of applications. To solve these bottlenecks, we present a new platform of single crystal SiC on an electrically insulating and transparent substrate using an anodic bonding process. The SiC thin film was prepared on a 150 mm Si with a surface roughness of 7 nm using LPCVD. The SiC/Si wafer was bonded to a glass substrate and then the Si layer was completely removed through wafer polishing and wet etching. The bonded SiC/glass s les show a sharp bonding interface of less than 15 nm characterized using deep profile X-ray photoelectron spectroscopy, a strong bonding strength of approximately 20 MPa measured from the pulling test, and relatively high optical transparency in the visible range. The transferred SiC film also exhibited good conductivity and a relatively high temperature coefficient of resistance varying from -12 000 to -20 000 ppm/K, which is desirable for thermal sensors. The biocompatibility of SiC/glass was also confirmed through mouse 3T3 fibroblasts cell-culturing experiments. Taking advantage of the superior electrical properties and biocompatibility of SiC, the developed SiC-on-glass platform offers unprecedented potentials for high-temperature electronics as well as bioapplications.
Surfactant-free, UV-curable core–shell microcapsules in a hydrophilic PDMS microfluidic device
Publisher: AIP Publishing
Date: 06-2020
DOI: 10.1063/5.0004736
Abstract: We demonstrate a method to create surfactant-free core–shell microcapsules in a hydrophilic polydimethylsiloxane microfluidic device. An ultraviolet light curable polymer was used to encapsulate an oil core. These microcapsules ensure contamination-free compartmentation of the core material without any surfactant, while maintaining the monodispersed generation at a rate of 100 microcapsules per second. The device fabrication process is greatly simplified without the alignment of microchannels and hydrophobic/hydrophilic surface treatment. After drying, physically shaking the collection chamber can crack the capsule to release the liquid core material. Such solid microcapsules with a liquid core are ideal for the storage and delivery of oil-based materials in skincare products or reagents for biochemical assays.
Reynolds numbers influence the directionality of self-propelled microjet engines in the 10−4 regime
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3NR01891A
Abstract: The motion directionality of self-propelled bubble-jet microengines is influenced by their velocities and/or viscosity of the media in which they move. The influence of the fuel concentration from 1 to 3 wt% of H2O2 in 0.5% steps and of the glycerol fraction from 0 to 64% in aqueous solution on the directionality of the microjets motions is examined systematically. We show that with decreasing Reynolds numbers of the system (that is, with increasing viscosity or decreasing velocity of the microjets), the directionality of the motion shifts from circular to linear motion. This translates to a shorter travel time towards a designated target for the microjets despite moving at a slower speed, since the movements are linear instead of circular. We show that such dependence of trajectories of microjets on Re is a general issue. This observation has a strong implication for the real-world applications of microjets.
Piezoresistive effect of p-type silicon nanowires fabricated by a top-down process using FIB implantation and wet etching
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA13425K
Abstract: This work reports the piezoresistance of silicon nanowires fabricated using focused ion beam and wet etching for NEMS mechanical sensors.
Thermocapillary effect of a liquid plug in transient temperature fields
Publisher: IOP Publishing
Date: 02-2005
DOI: 10.1143/JJAP.44.1139
Abstract: In this paper we present the theoretical and experimental results of thermocapillary effects of liquid plugs in a long capillary, which is exposed to a transient temperature gradient. A one-dimensional analytical model is formulated for the dynamic behavior of a liquid droplet, which is driven by the thermocapillary effect under a transient temperature field. The thermocapillary actuation concept can be used for liquid transport in microfluidics. In microfluidic applications, the temperature field is often induced by the activation of integrated heaters. The generated temperature field and temperature gradient drive a liquid droplet according to the temperature-dependent surface tension. In the initial stage, the transient temperature gradient spreads in the capillary wall much slower than the droplet itself, and thus leads to an interesting behavior of droplet motion as described in this paper. Experiments were carried out for liquid droplets with different viscosities in long glass capillaries with different radii. The capillaries are exposed to a resistive heater at one of its ends. The analytically predicted behavior of the droplet motion agrees qualitatively well with the measurement.
Correction: Gold-loaded nanoporous iron oxide nanocubes: a novel dispersible capture agent for tumor-associated autoantibody analysis in serum
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7NR90194A
Abstract: Correction for ‘Gold-loaded nanoporous iron oxide nanocubes: a novel dispersible capture agent for tumor-associated autoantibody analysis in serum’ by Sharda Yadav et al. , Nanoscale , 2017, 9 , 8805–8814.
Improved capillary electrophoresis separation using a capillary bundle
Publisher: ASMEDC
Date: 2008
Abstract: Joule heating is an undesirable effect in capillary electrophoresis (CE). The heat generated by the electrical current leads to a temperature gradient along the separation channel and consequently affects the separation quality. Since the heat is inversely proportional to the electric resistance of the separation column, increasing the electric resistance can reduce the effect of Joule heating. Currently, due to the limit of fabrication technique and detection apparatus, the typical dimensions of CE microchannels are in the range of 50 μm to 200 μm. In this paper, we describe the method of reducing the cross-sectional area of the separation channel and increasing the channel’s surface for better heat dissipation. A photonic crystal fiber (PCF) is a bundle of extremely narrow channels, which ideally work as separation columns. The PCF was simply encapsulated in a polymethylmethacrylate (PMMA) microchannel right after a T-shaped injector. CE was simultaneously but independently carried out in 54 narrow capillaries, each capillary with diameter of 3.7 μm. The capillary bundle could sustain high electric field strength up to 1000 V/cm due to efficient heat dissipation, thus faster and enhanced separation was attained.
Fabrication of nanochannels in silicon and polymers
Publisher: ASMEDC
Date: 2008
Abstract: This paper reports the fabrication of planar nanochannels in silicon and thermoplastic. Conventional technologies such as reactive ion etching (RIE) and anodic bonding were used for fabricating the silicon-based nanochannels, while hot embossing and thermal bonding were used for polymer-based nanochannels. Due to the limit of photolithography, the lateral dimension of the channels are kept on the order of micrometers. The depth can be controlled precisely by etch rate or deposition rate. While fabrication technologies for nanochannels in silicon and glass are established and straightforward to implement, fabrication of planar nanochannels in a plastic is challenging because of the more severe collapsing of the structure during bonding. Besides the silicon technology, we demonstrate a simple and low-cost fabrication technology of planar nanochannels by hot-embossing in a thermoplastic and bonding below the glass transition temperature.
Microfluidic-Based Nucleic Acid Amplification Systems in Microbiology
Publisher: MDPI AG
Date: 19-06-2019
DOI: 10.3390/MI10060408
Abstract: Rapid, sensitive, and selective bacterial detection is a hot topic, because the progress in this research area has had a broad range of applications. Novel and innovative strategies for detection and identification of bacterial nucleic acids are important for practical applications. Microfluidics is an emerging technology that only requires small amounts of liquid s les. Microfluidic devices allow for rapid advances in microbiology, enabling access to methods of lifying nucleic acid molecules and overcoming difficulties faced by conventional. In this review, we summarize the recent progress in microfluidics-based polymerase chain reaction devices for the detection of nucleic acid biomarkers. The paper also discusses the recent development of isothermal nucleic acid lification and droplet-based microfluidics devices. We discuss recent microfluidic techniques for s le preparation prior to the lification process.
Numerical study of thermocoalescence of microdroplets in a microfluidic chamber
Publisher: AIP Publishing
Date: 08-2013
DOI: 10.1063/1.4819134
Abstract: The present paper reports the numerical investigation of thermocoalescence of droplets in a microchannel network consisting of a droplet formation section connecting to a temperature-induced merging chamber. The numerical model is formulated as an incompressible immiscible two-phase flow problem with oil and water as the continuous and dispersed phase, respectively. The governing equations are solved using finite volume method on a staggered mesh. The interface is captured by a narrow-band particle level-set method. The paper examines the droplet formation process and droplet size at 4 different ratios of oil and water flow rate. The motion of the droplets from the formation section into and through the heat-induced merging chamber is analyzed. The numerical method is able to provide a visual presentation of the droplet movement in a heated environment under the influence of thermocapillarity. The relationship between the critical merging temperature and the fluid flow rate is also analyzed and discussed.
Detection of regional DNA methylation using DNA-graphene affinity interactions
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.BIOS.2016.09.016
Abstract: We report a new method for the detection of regional DNA methylation using base-dependent affinity interaction (i.e., adsorption) of DNA with graphene. Due to the strongest adsorption affinity of guanine bases towards graphene, bisulfite-treated guanine-enriched methylated DNA leads to a larger amount of the adsorbed DNA on the graphene-modified electrodes in comparison to the adenine-enriched unmethylated DNA. The level of the methylation is quantified by monitoring the differential pulse voltammetric current as a function of the adsorbed DNA. The assay is sensitive to distinguish methylated and unmethylated DNA sequences at single CpG resolution by differentiating changes in DNA methylation as low as 5%. Furthermore, this method has been used to detect methylation levels in a collection of DNA s les taken from oesophageal cancer tissues.
A polymeric microgripper with integrated thermal actuators
Publisher: IOP Publishing
Date: 21-05-2004
Highly sensitive p-type 4H-SiC van der Pauw sensor
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7RA11922D
Abstract: This paper presents for the first time a p-type 4H silicon carbide (4H-SiC) van der Pauw strain sensor by utilizing the strain induced effect in four-terminal devices.
Dynamic Behaviour of Monodisperse Double Emulsion Formation in a Tri-axial Capillary Device
Publisher: MDPI AG
Date: 14-10-2022
DOI: 10.20944/PREPRINTS202210.0213.V1
Abstract: We investigated experimentally, analytically and numerically the formation process of double emulsion formations under dripping regime in a tri-axial co-flow capillary device. The results show that mismatches of core and shell droplets under a given flow condition can be captured both experimentally and numerically. We propose a semi-analytical model using the match ratio between the pinch-off length of the shell droplet and the product of the core growth rate and its pinch-off time. The mismatch issue can be avoided if the match ratio is lower than unity. We considered a model with the wall effect to predict the size of the matched double emulsion. The model shows slight deviations with experimental data if the Reynolds number of continuous phase is lower than 0.06, but asymptotically approaches to good agreement if the Reynolds number increases from 0.06 to 0.14. The numerical simulation generally agrees with the experiments under various flow conditions.
Deformation of a floating liquid marble.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4SM02882A
Abstract: We report the analytical and experimental characterisation of the deformation of a liquid marble floating on a liquid surface.
On-Demand Droplet Merging with an AC Electric Field for Multiple-Volume Droplet Generation
Publisher: American Chemical Society (ACS)
Date: 25-11-2020
DOI: 10.1021/ACS.ANALCHEM.9B04219
Abstract: We introduce a unique system to achieve on-demand droplet merging and splitting using a perpendicular AC electric field. The working mechanism involves a micropillar to split droplets, followed by electrocoalescence using an AC electric field. Adjusting the parameters of the AC signal and conductivity of the fluid result in different merging regimes. We observed a minimum threshold voltage and a strong influence of the surfactant. We hypothesize that the merging process is caused by dipole-dipole coalescence between the daughter droplets. At the same time, adjustment of the conductivity reveals a shift in the merging regimes and can be explained with an electric circuit diagram. Size-based sorting using this merging phenomenon is subsequently demonstrated, where alternate, single, double, and triple droplets sorting were achieved. The concept presented in this paper is potentially useful for drug dispensing or multivolume digital polymerase chain reaction, as droplets of multiple sizes can be generated simultaneously.
Core–Shell Particles: From Fabrication Methods to Diverse Manipulation Techniques
Publisher: MDPI AG
Date: 21-02-2023
DOI: 10.3390/MI14030497
Abstract: Core–shell particles are micro- or nanoparticles with solid, liquid, or gas cores encapsulated by protective solid shells. The unique composition of core and shell materials imparts smart properties on the particles. Core–shell particles are gaining increasing attention as tuneable and versatile carriers for pharmaceutical and biomedical applications including targeted drug delivery, controlled drug release, and biosensing. This review provides an overview of fabrication methods for core–shell particles followed by a brief discussion of their application and a detailed analysis of their manipulation including assembly, sorting, and triggered release. We compile current methodologies employed for manipulation of core–shell particles and demonstrate how existing methods of assembly and sorting micro/nanospheres can be adopted or modified for core–shell particles. Various triggered release approaches for diagnostics and drug delivery are also discussed in detail.
Core -Shell Particles: from Fabrication Methods to Diverse Manipulation Techniques
Publisher: MDPI AG
Date: 26-12-2022
DOI: 10.20944/PREPRINTS202212.0463.V1
Abstract: Core-shell particles are heterogenous micro- or nanoparticles with solid, liquid or gas core encapsulated by a protective solid shell. The unique composition of core and shell materials imparts smart properties to the particles. Core-shell particles are gaining increasing attention as tuneable and versatile carriers for pharmaceutical and biomedical applications including targeted drug delivery, controlled drug release, and biosensing. This review first provides an overview of fabrication methods for core-shell particles, followed by a brief discussion on their application and a detailed analysis on manipulation including assembly, sorting, and triggered release. We compile current methodologies employed for manipulation of core-shell particles and demonstrate how existing methods of assembly and sorting micro/nanospheres can be adopted or modified for core-shell particles. Various triggered release approaches for diagnostics and drug delivery are also discussed in detail.
Superior Robust Ultrathin Single-Crystalline Silicon Carbide Membrane as a Versatile Platform for Biological Applications
Publisher: American Chemical Society (ACS)
Date: 20-11-2017
Abstract: Micromachined membranes are promising platforms for cell culture thanks to their miniaturization and integration capabilities. Possessing chemical inertness, biocompatibility, and integration, silicon carbide (SiC) membranes have attracted great interest toward biological applications. In this paper, we present the batch fabrication, mechanical characterizations, and cell culture demonstration of robust ultrathin epitaxial deposited SiC membranes. The as-fabricated ultrathin SiC membranes, with an ultrahigh aspect ratio (length/thickness) of up to 20 000, possess high a fracture strength up to 2.95 GPa and deformation up to 50 μm. A high optical transmittance of above 80% at visible wavelengths was obtained for 50 nm membranes. The as-fabricated membranes were experimentally demonstrated as an excellent substrate platform for bio-MEMS/NEMS cell culture with the cell viability rate of more than 92% after 72 h. The ultrathin SiC membrane is promising for in vitro observations/imaging of bio-objects with an extremely short optical access.
Impact of carrier injections on the threshold voltage in p-GaN gate AlGaN/GaN power HEMTs
Publisher: IOP Publishing
Date: 08-05-2019
The Informal Sector: A Review and Agenda for Management Research
Publisher: Wiley
Date: 15-12-2016
DOI: 10.1111/IJMR.12131
Fundamentals and applications of inertial microfluidics: a review
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5LC01159K
Abstract: We provide a comprehensive review describing the fundamental mechanisms of inertial microfluidics, structure design and applications in biology, medicine and industry.
Fluorescent Immunological Paper-based Assay for Exosome detection
Publisher: Research Square Platform LLC
Date: 12-10-2021
DOI: 10.21203/RS.3.RS-963221/V1
Abstract: This paper reports the development of fluorescent-linked immunosorbent paper-based assay for exosome detection. The paper-based device was fabricated with sandwich lamination for easy handling and was coated with exosome-specific antibody as a biosensing platform to detect exosome s le from the cell culture media. This assay employed fluorescent detection which is followed by tagging fluorophore-conjugated detecting antibody on exosome s les. The fluorescent readout was evaluated and quantified from image processing software. This assay can detect high concentration of exosome s les (~ 10 10 exosome/mL). However, this assay has encountered various challenges. First, the exosome concentration prepared from cell culture media from cancer-derived ovarian and mesothelial cell lines may be insufficient to reach detectable range. Second, chemical contamination from exosome isolation kits may affect assay sensitivity. Therefore, assay optimization and minimizing chemical contamination are required which could enhance assay specificity and sensitivity.
Liquid marbles as bioreactors for the study of three-dimensional cell interactions
Publisher: Springer Science and Business Media LLC
Date: 18-04-2017
DOI: 10.1007/S10544-017-0171-6
Abstract: Liquid marble as a bioreactor platform for cell-based studies has received significant attention, especially for developing 3D cell-based assays. This platform is particularly suitable for 3D in-vitro modeling of cell-cell interactions. For the first time, we demonstrated the interaction of olfactory ensheathing cells (OECs) with nerve debris and meningeal fibroblast using liquid marbles. As the transplantation of OECs can be used for repairing nerve injury, degenerating cell debris within the transplantation site can adversely affect the survival of transplanted OECs. In this paper, we used liquid marbles to mimic the hostile 3D environment to analyze the functional behavior of the cells and to form the basis for cell-based therapy. We show that OECs interact with debris and enhanced cellular aggregation to form a larger 3D spheroidal tissue. However, these spheroids indicated limitation in biological functions such as the inability of cells within the spheroids to migrate out and adherence to neighboring tissue by fusion. The coalescence of two liquid marbles allows for analyzing the interaction between two distinct cell types and their respective environment. We created a microenvironment consisting of 3D fibroblast spheroids and nerve debris and let it interact with OECs. We found that OECs initiate adherence with nerve debris in this 3D environment. The results suggest that liquid marbles are ideal for developing bioassays that could substantially contribute to therapeutic applications. Especially, insights for improving the survival and adherence of transplanted cells.
Experimental Investigation of Piezoresistive Effect in p-Type 4H–SiC
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2017
Motion of a droplet through microfluidic ratchets
Publisher: American Physical Society (APS)
Date: 27-10-2009
Wireless Battery-Free SiC Sensors Operating in Harsh Environments Using Resonant Inductive Coupling
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2019
A floating self-propelling liquid marble containing aqueous ethanol solutions
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA23946J
Abstract: We report the behaviour of a self-propelling liquid marble containing an aqueous ethanol solution.
An amplification-free method for the detection of HOTAIR long non-coding RNA
Publisher: Elsevier BV
Date: 10-2020
AlGaN/GaN 2-D Electron Gas for Highly Sensitive and High-Temperature Current Sensing
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2021
Recent Patents on Biclustering Algorithms for Gene Expression Data Analysis
Publisher: Bentham Science Publishers Ltd.
Date: 08-2011
DOI: 10.2174/187221511796392097
Abstract: In DNA microarray experiments, discovering groups of genes that share similar transcriptional characteristics is instrumental in functional annotation, tissue classification and motif identification. However, in many situations a subset of genes only exhibits a consistent pattern over a subset of conditions. Although used extensively in gene expression data analysis, conventional clustering algorithms that consider the entire row or column in an expression matrix can therefore fail to detect useful patterns in the data. Recently, biclustering has been proposed as a powerful computational tool to detect subsets of genes that exhibit consistent pattern over subsets of conditions. In this article, we review several recent patents in bicluster analysis, and in particular, highlight a recent patent from our group about a novel geometric-based biclustering method that handles the class of bicluster patterns with linear coherent variation across the row and/or column dimension. This class of bicluster patterns is of particular importance since it subsumes all constant, additive, and multiplicative bicluster patterns normally used in gene expression data analysis.
Dependence of offset voltage in AlGaN/GaN van der Pauw devices under mechanical strain
Publisher: Elsevier BV
Date: 06-2019
Generation and manipulation of monodispersed ferrofluid emulsions: The effect of a uniform magnetic field in flow-focusing and T-junction configurations
Publisher: American Physical Society (APS)
Date: 21-09-2011
Enhancing malaria diagnosis through microfluidic cell enrichment and magnetic resonance relaxometry detection
Publisher: Springer Science and Business Media LLC
Date: 17-06-2015
DOI: 10.1038/SREP11425
Abstract: Despite significant advancements over the years, there remains an urgent need for low cost diagnostic approaches that allow for rapid, reliable and sensitive detection of malaria parasites in clinical s les. Our previous work has shown that magnetic resonance relaxometry (MRR) is a potentially highly sensitive tool for malaria diagnosis. A key challenge for making MRR based malaria diagnostics suitable for clinical testing is the fact that MRR baseline fluctuation exists between in iduals, making it difficult to detect low level parasitemia. To overcome this problem, it is important to establish the MRR baseline of each in idual while having the ability to reliably determine any changes that are caused by the infection of malaria parasite. Here we show that an approach that combines the use of microfluidic cell enrichment with a saponin lysis before MRR detection can overcome these challenges and provide the basis for a highly sensitive and reliable diagnostic approach of malaria parasites. Importantly, as little as 0.0005% of ring stage parasites can be detected reliably, making this ideally suited for the detection of malaria parasites in peripheral blood obtained from patients. The approaches used here are envisaged to provide a new malaria diagnosis solution in the near future.
Rapid, Simple and Inexpensive Fabrication of Paper-Based Analytical Devices by Parafilm® Hot Pressing
Publisher: MDPI AG
Date: 29-12-2022
DOI: 10.3390/MI13010048
Abstract: Paper-based analytical devices have been substantially developed in recent decades. Many fabrication techniques for paper-based analytical devices have been demonstrated and reported. Herein, we report a relatively rapid, simple, and inexpensive method for fabricating paper-based analytical devices using parafilm hot pressing. We studied and optimized the effect of the key fabrication parameters, namely pressure, temperature, and pressing time. We discerned the optimal conditions, including a pressure of 3.8 MPa, temperature of 80 °C, and 3 min of pressing time, with the smallest hydrophobic barrier size (821 µm) being governed by laminate mask and parafilm dispersal from pressure and heat. Physical and biochemical properties were evaluated to substantiate the paper functionality for analytical devices. The wicking speed in the fabricated paper strips was slightly lower than that of non-processed paper, resulting from a reduced paper pore size after hot pressing. A colorimetric immunological assay was performed to demonstrate the protein binding capacity of the paper-based device after exposure to pressure and heat from the fabrication. Moreover, mixing in a two-dimensional paper-based device and flowing in a three-dimensional counterpart were thoroughly investigated, demonstrating that the paper devices from this fabrication process are potentially applicable as analytical devices for biomolecule detection. Fast, easy, and inexpensive parafilm hot press fabrication presents an opportunity for researchers to develop paper-based analytical devices in resource-limited environments.
Microfluidic rheometer based on hydrodynamic focusing
Publisher: IOP Publishing
Date: 30-06-2008
Simple, Cost-Effective, and Continuous 3D Dielectrophoretic Microchip for Concentration and Separation of Bioparticles
Publisher: American Chemical Society (ACS)
Date: 16-04-2019
Microfluidic on-chip fluorescence-activated interface control system
Publisher: AIP Publishing
Date: 22-11-2010
DOI: 10.1063/1.3516036
Abstract: A microfluidic dynamic fluorescence-activated interface control system was developed for lab-on-a-chip applications. The system consists of a straight rectangular microchannel, a fluorescence excitation source, a detection sensor, a signal conversion circuit, and a high-voltage feedback system. Aqueous NaCl as conducting fluid and aqueous glycerol as nonconducting fluid were introduced to flow side by side into the straight rectangular microchannel. Fluorescent dye was added to the aqueous NaCl to work as a signal representing the interface position. Automatic control of the liquid interface was achieved by controlling the electroosmotic effect that exists only in the conducting fluid using a high-voltage feedback system. A LABVIEW program was developed to control the output of high-voltage power supply according the actual interface position, and then the interface position is modified as the output of high-voltage power supply. At last, the interface can be moved to the desired position automatically using this feedback system. The results show that the system presented in this paper can control an arbitrary interface location in real time. The effects of viscosity ratio, flow rates, and polarity of electric field were discussed. This technique can be extended to switch the s le flow and droplets automatically.
SU-8 as a structural material for labs-on-chips and microelectromechanical systems
Publisher: Wiley
Date: 12-2007
Abstract: Since its introduction in the nineties, the negative resist SU-8 has been increasingly used in micro- and nanotechnologies. SU-8 has made the fabrication of high-aspect ratio structures accessible to labs with no high-end facilities such as X-ray lithography systems or deep reactive ion etching systems. These low-cost techniques have been applied not only in the fabrication of metallic parts or molds, but also in numerous other micromachining processes. Its ease of use has made SU-8 to be used in many applications, even when high-aspect ratios are not required. Beyond these pattern transfer applications, SU-8 has been used directly as a structural material for microelectromechanical systems and microfluidics due to its properties such as its excellent chemical resistance or the low Young modulus. In contrast to conventional resists, which are used temporally, SU-8 has been used as a permanent building material to fabricate microcomponents such as cantilevers, membranes, and microchannels. SU-8-based techniques have led to new low-temperature processes suitable for the fabrication of a wide range of objects, from the single component to the complete lab-on-chip. First, this article aims to review the different techniques and provides guidelines to the use of SU-8 as a structural material. Second, practical ex les from our respective labs are presented.
Circulating tumor DNA and liquid biopsy: opportunities, challenges, and recent advances in detection technologies
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8LC00100F
Abstract: Opportunities and challenges in translational application of ctDNA along with recent developments in chip-based ctDNA detection technologies have been reviewed.
Active droplet sorting in microfluidics: a review
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6LC01435F
Abstract: This review presents the fundamentals of different active methods for sorting droplets in microfluidics.
Micro-optofluidic Lenses: A review
Publisher: AIP Publishing
Date: 19-07-2010
DOI: 10.1063/1.3460392
Abstract: This review presents a systematic perspective on the development of micro-optofluidic lenses. The progress on the development of micro-optofluidic lenses are illustrated by ex le from recent literature. The advantage of micro-optofluidic lenses over solid lens systems is their tunability without the use of large actuators such as servo motors. Depending on the relative orientation of light path and the substrate surface, micro-optofluidic lenses can be categorized as in-plane or out-of-plane lenses. However, this review will focus on the tunability of the lenses and categorizes them according to the concept of tunability. Micro-optofluidic lenses can be either tuned by the liquid in use or by the shape of the lens. Micro-optofluidic lenses with tunable shape are categorized according to the actuation schemes. Typical parameters of micro-optofluidic lenses reported recently are compared and discussed. Finally, perspectives are given for future works in this field.
Formation and manipulation of ferrofluid droplets at a microfluidicT-junction
Publisher: IOP Publishing
Date: 05-03-2010
Dynamic behaviour of a magnetically actuated floating liquid marble
Publisher: Springer Science and Business Media LLC
Date: 06-2017
An electromagnetic cell-stretching device for mechanotransduction studies of olfactory ensheathing cells
Publisher: Springer Science and Business Media LLC
Date: 19-05-2016
DOI: 10.1007/S10544-016-0071-1
Abstract: Olfactory ensheathing cells (OECs) are primary candidates for cell transplantation therapy to repair spinal cord injury (SCI). However, the post transplantation survival of these cells remains a major hurdle for a success using this therapy. Mechanical stimuli may contribute to the maintenance of these cells and thus, mechanotransduction studies of OECs may serve as a key benefit to identify strategies for improvement in cell transplantation. We developed an electromagnetic cell stretching device based on a single sided uniaxial stretching approach to apply tensile strain to OECs in culture. This paper reports the design, simulation and characterisation of the stretching device with preliminary experimental observations of OECs in vitro. The strain field of the deformable membrane was investigated both experimentally and numerically. Heterogeneity of the device provided an ideal platform for establishing strain requirement for the OEC culture. The cell stretching system developed may serve as a tool in exploring the mechanobiology of OECs for future SCI transplantation research.
Asymmetrical locations of heaters and sensors relative to each other using heater arrays: a novel method for designing multi-range electrocaloric mass-flow sensors
Publisher: Elsevier BV
Date: 07-1997
Electrochemical detection of global dna methylation using biologically assembled polymer beads
Publisher: MDPI AG
Date: 27-07-2021
Abstract: DNA methylation is a cell-type-specific epigenetic marker that is essential for transcriptional regulation, silencing of repetitive DNA and genomic imprinting. It is also responsible for the pathogenesis of many diseases, including cancers. Herein, we present a simple approach for quantifying global DNA methylation in ovarian cancer patient plasma s les based on a new class of biopolymer nanobeads. Our approach utilises the immune capture of target DNA and electrochemical quantification of global DNA methylation level within the targets in a three-step strategy that involves (i) initial preparation of target single-stranded DNA (ss-DNA) from the plasma of the patients’ s les, (ii) direct adsorption of polymer nanobeads on the surface of a bare screen-printed gold electrode (SPE-Au) followed by the immobilisation of 5-methylcytosine (5mC)-horseradish peroxidase (HRP) antibody, and (iii) immune capture of target ss-DNA onto the electrode-bound PHB/5mC-HRP antibody conjugates and their subsequent qualification using the hydrogen peroxide/horseradish peroxidase/hydroquinone (H2O2/HRP/HQ) redox cycling system. In the presence of methylated DNA, the enzymatically produced (in situ) metabolites, i.e., benzoquinone (BQ), binds irreversibly to cellular DNA resulting in the unstable formation of DNA adducts and induced oxidative DNA strand breakage. These events reduce the available BQ in the system to support the redox cycling process and sequel DNA saturation on the platform, subsequently causing high Coulombic repulsion between BQ and negatively charged nucleotide strands. Thus, the increase in methylation levels on the electrode surface is inversely proportional to the current response. The method could successfully detect as low as 5% methylation level. In addition, the assay showed good reproducibility (% RSD ≤ 5%) and specificity by analysing various levels of methylation in cell lines and plasma DNA s les from patients with ovarian cancer. We envision that our bioengineered polymer nanobeads with high surface modification versatility could be a useful alternative platform for the electrochemical detection of varying molecular biomarkers.
Automated droplet measurement (ADM): an enhanced video processing software for rapid droplet measurements
Publisher: Springer Science and Business Media LLC
Date: 04-2016
A Paper-based Immunofluorescent Device for the Detection of SARS-CoV-2 Humanized Antibody
Publisher: MDPI AG
Date: 07-07-2021
DOI: 10.20944/PREPRINTS202107.0181.V1
Abstract: We report on an immunofluorescent paper-based assay for the detection of severe acute respiratory symptom coronavirus 2 (SARS-CoV-2) humanized antibody. The paper-based device was fabricated by using lamination technique for easy and optimized handling. Our approach utilises a two-step strategy that involves (i) initial coating of the paper-electrode with recombinant SARS-CoV-2 nucleocapsid antigen to capture the target SARS-CoV-2 specific antibodies, and (ii) subsequent detection of SARS-CoV-2 antibodies using fluorophore-conjugated IgG antibody. The fluorescence readout was observed with fluorescence microscopy. The images were processed and quantified using a MATLAB program. The assay can selectively detect SARS-CoV-2 humanized antibodies spiked in PBS and healthy human serum s les with the relative standard deviation of approximately 6.4% (for n = 3). It has broad dynamic ranges (1 ng to 50 ng/& micro L in PBS and 5 to 100 ng/& micro L in human serum s les) for SARS-CoV-2 humanized antibodies with the detection limits of 2 ng/& micro L (0.025 IU/mL) and 10 ng/& micro L (0.125 IU/mL) in PBS and human serum s les, respectively. We believe that our assay has the potential to be used as a simple, rapid, and inexpensive paper-based diagnostic device with a portable fluorescent reader to provide point-of-care diagnosis. This assay can be used for rapid examination of a large batch of s les toward clinical screening of SARS-CoV-2 specific antibodies as a confirmed infected active case or to evaluate the immune response to a SARS-CoV-2 vaccine.
Particle Transport In Microchannels
Publisher: ASMEDC
Date: 2006
Abstract: A numerical model for particle transport in microchannel is presented. This article focuses on situations where the sizes of the particles are comparable to the sizes of the channels. The present approach is validated against (1) flow around stationary, (2) flow around forced rotating, (3) flow around freely rotating cylinders and (4) sedimentation of a circular cylinder under gravity. With the present model, the motion of particles carried by an incompressible fluid in a microchannel system is studied.
Integration of PDMS and PMMA for batch fabrication of microfluidic devices
Publisher: Springer Berlin Heidelberg
Date: 2010
Digital Imaging‐based Colourimetry for Enzymatic Processes in Transparent Liquid Marbles
Publisher: Wiley
Date: 26-11-2020
Tuning particle inertial separation in sinusoidal channels by embedding periodic obstacle microstructures
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2LC00197G
Abstract: This work proposed to tune particle inertial separation in sinusoidal channels by embedding periodic obstacle microstructures and developed a cascaded inertial microfluidic device for the high-efficiency isolation of rare cells.
Precise, wide field, and low-cost imaging and analysis of core–shell beads for digital polymerase chain reaction
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3LC00337J
Abstract: This study introduces a core–shell bead-based digital PCR platform, where PCR mix is enclosed in microfluidic beads. Multiple flow focusing stages in the device facilitate bead formation. Results of digital PCR are effectively compared with RT-qPCR.
Effects of photogenerated-hole diffusion on 3C-SiC/Si heterostructure optoelectronic position-sensitive detector
Publisher: IOP Publishing
Date: 16-04-2021
Abstract: Single-crystalline silicon carbide (3C-SiC) has been attracting significant attention in recent years due to its cost-effectiveness and high crystalline quality, mature fabrication techniques on Si-substrate and outstanding mechanical, chemical, and optoelectronic characteristics. Taking advantage of its large built-in potential, a promising application of 3C-SiC on Si (3C-SiC/Si) heterostructure is to develop position-sensitive detectors (PSDs) based on the lateral photovoltaic effect. The lateral photovoltage is generated under non-uniform illumination due to the asymmetry diffusion of photo-induced charge carriers. However, the full potential of 3C-SiC/Si heterojunction-based PSDs has not been elucidated yet. In this study, we investigate the influence of photogenerated hole and its diffusion path length on the sensing performance of the devices in attempts to obtain an optimal design and further pushing the limit of the PSD. Devices with different electrode spacings are fabricated on the 3C-SiC/Si heterostructure, and experiments are conducted under different illumination conditions to determine the position-sensitivity. Devices with short electrode spacings are found to have excellent position-sensitivity with the highest sensitivity of 470 mV mm −1 obtained in a device spacing of 300 µ m under 980 nm (1000 µ W) laser illumination. The physic mechanism underneath the experimentally observed behaviors are explained based on the generation and separation of electron–hole (e–h) pairs under the illumination, and charge carrier diffusion theory. The findings of this work will provide insights to design highly sensitive PSDs and explore its full potentials.
Transport of magnetic particles under a uniform magnetic field in microchannels
Publisher: American Society of Mechanical Engineers
Date: 16-06-2013
Abstract: This paper reports the numerical and experimental investigation on magnetic particle concentration in a uniform magnetic field. The flow system consists of water-based ferrofluid and glycerol/DI water mixture streams. Two regimes were observed with spreading and mixing phenomena. With a low magnetic field strength, the spread of magnetic particles is caused by improved diffusion migration. With a relatively high field strength, instability at the interface would occur due to the mismatch in magnetization of the fluid streams. The transport of magnetic particles is induced by chaotic mixing of the fluids caused by a secondary flow. The mixing phenomena are characterized by magnetic flux density. For configuration with flow rate and viscosity ratio (between diamagnetic and magnetic streams) being set at 1 and 0.5, the mixing efficiency analyzed based on magnetic particles concentration increases approximately by 0.3 at around 3.5 mT. This value of magnetic flux density indicates the requirement on instability inception. The mixing efficiency increases with magnetic flux density increases further. Complete mixing can be achieved with a magnetic flux density at around 10 mT. The magnetic approach offers a wireless, heat-free and pH-independent solution for a lab-on-a-chip system.
A Procedure for the Motion of Particle-Encapsulated Droplets in Microchannels
Publisher: Informa UK Limited
Date: 29-10-2008
A method for simultaneously determining the zeta potentials of the channel surface and the tracer particles using microparticle image velocimetry technique
Publisher: Wiley
Date: 02-2006
Abstract: The zeta potentials of channel surfaces and tracer particles are of importance to the design of electrokinetic microfluidic devices, the characterization of channel materials, and the quantification of the microparticle image velocimetry (microPIV) measurement of EOFs. A method is proposed to simultaneously measure the zeta potentials of the channel surface and the tracer particles in aqueous solutions using the microPIV technique. Through the measurement of the steady velocity distributions of the tracer particles in both open- and closed-end rectangular microchannels under the same water chemistry condition, the electrophoretic velocity of the tracer particles and the EOF field of the microchannel are determined using the expressions derived in this study for the velocity distributions of charged tracer particles in the open- and closed-end rectangular microchannels. Thus, the zeta potentials of the tracer particles and the channel surfaces are simultaneously obtained using the least-square method to fit the microPIV measured velocity distribution of the tracer particles. Measurements were carried out with a microPIV system to determine the zeta potentials of the channel wall and the fluorescent tracer particles in deionized water and sodium chloride and boric acid solutions of various concentrations.
Thermocoalescence of microdroplets in a microfluidic chamber
Publisher: AIP Publishing
Date: 18-06-2012
DOI: 10.1063/1.4730606
Abstract: Droplet coalescence plays an important role in droplet-based microfluidics. This letter reports the phenomenon of thermocoalescence of two droplets in a chamber with a microheater. An integrated resistive sensor allows the measurement of heating temperature. The merging process was investigated at different flow rates. Experimental results showed that the droplet slows down at increasing temperature and eventually merges with the subsequent droplet. Coalescence occurs at a critical heating temperature. The letter discusses the relationship between droplet velocity, critical merging temperature, and flow rates.
Semi-analytical model of mixed electroosmotic/pressure driven two immiscible fluids with curved interface
Publisher: Bentham Science Publishers Ltd.
Date: 12-2011
Miniature valveless pumps based on printed circuit board technique
Publisher: Elsevier BV
Date: 02-2001
Graphite on paper as material for sensitive thermoresistive sensors
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TC01650A
Abstract: We report on the thermoresistive properties of graphite on paper (GOP). A large temperature coefficient of resistance was observed and a highly sensitive GOP-based anemometer was demonstrated, indicating strong feasibility of using the GOP for low-cost thermoresistive sensors.
Signal-Based Methods in Dielectrophoresis for Cell Separation
Publisher: MDPI AG
Date: 20-06-2022
DOI: 10.20944/PREPRINTS202206.0261.V1
Abstract: Separation and detection of cells and particles in a suspension are essential for various applications, including biomedical investigations and clinical diagnostics. Microfluidics realizes the miniaturization of analytical devices by controlling the motion of a small volume of fluids in microchannels and microchambers. Accordingly, microfluidic devices have been widely used in particle/ cell manipulation processes. Different microfluidic methods for particle separation include dielectrophoretic, magnetic, optical, acoustic, hydrodynamic, and chemical techniques. Dielectrophoresis (DEP) is a method for manipulating polarizable particles& rsquo trajectories in non-uniform electric fields using unique dielectric characteristics. It provides several advantages for dealing with neutral bioparticles owing to its sensitivity, selectivity, and noninvasive nature. This review provides a detailed study on the signal-based DEP methods that use the applied signal parameters, including frequency, litude, phase, and shape for cell article separation and manipulation. Rather than employing complex channels or time-consuming fabrication procedures, these methods realize sorting and detecting the cells articles by modifying the signal parameters while using a simple device. In addition, these methods can significantly impact clinical diagnostics by making low-cost and rapid separation possible.
A review on membraneless laminar flow-based fuel cells
Publisher: Elsevier BV
Date: 05-2011
Ensembles of Photonic Beads: Optical Properties and Enhanced Light—Matter Interactions
Publisher: Wiley
Date: 22-01-2020
Nanoarchitectonics for Wide Bandgap Semiconductor Nanowires: Toward the Next Generation of Nanoelectromechanical Systems for Environmental Monitoring
Publisher: Wiley
Date: 24-09-2020
Spheroids-on-a-chip: Recent advances and design considerations in microfluidic platforms for spheroid formation and culture
Publisher: Elsevier BV
Date: 06-2018
Localized Surface Plasmon Enhanced Laser Reduction of Graphene Oxide for Wearable Strain Sensor
Publisher: Wiley
Date: 31-03-2021
A rapid and cost-effective metallization technique for 3C–SiC MEMS using direct wire bonding
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8RA00734A
Abstract: This paper presents a simple, rapid and cost-effective wire bonding technique for single crystalline silicon carbide (3C–SiC) MEMS devices.
A continuous-flow droplet-based concentrator using ion concentration polarization
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA07491F
Abstract: We reports the continuous generation of droplets with concentrated s le conditioned ion concentration polarization.
Fabrication of nanoporous junctions using off-the-shelf Nafion membrane
Publisher: IOP Publishing
Date: 09-10-2015
Optical biosensing strategies for DNA methylation analysis
Publisher: Elsevier BV
Date: 06-2017
DOI: 10.1016/J.BIOS.2016.10.034
Abstract: DNA methylation is an epigenetic modification of DNA, where a methyl group is added at the fifth carbon of the cytosine base to form 5 methyl cytosine (5mC) without altering the DNA sequences. It plays important roles in regulating many cellular processes by modulating key genes expression. Alteration in DNA methylation patterns becomes particularly important in the aetiology of different diseases including cancers. Abnormal methylation pattern could contribute to the pathogenesis of cancer either by silencing key tumor suppressor genes or by activating oncogenes. Thus, DNA methylation biosensing can help in the better understanding of cancer prognosis and diagnosis and aid the development of therapies. Over the last few decades, a plethora of optical detection techniques have been developed for analyzing DNA methylation using fluorescence, Raman spectroscopy, surface plasmon resonance (SPR), electrochemiluminescence and colorimetric readouts. This paper aims to comprehensively review the optical strategies for DNA methylation detection. We also present an overview of the remaining challenges of optical strategies that still need to be focused along with the lesson learnt while working with these techniques.
Modeling of mass transfer enhancement in a magnetofluidic micromixer
Publisher: AIP Publishing
Date: 06-2019
DOI: 10.1063/1.5093498
Abstract: The use of magnetism for various microfluidic functions such as separation, mixing, and pumping has been attracting great interest from the research community as this concept is simple, effective, and of low cost. Magnetic control avoids common problems of active microfluidic manipulation such as heat, surface charge, and high ionic concentration. The majority of past works on micromagnetofluidic devices were experimental, and a comprehensive numerical model to simulate the fundamental transport phenomena in these devices is still lacking. The present study aims to develop a numerical model to simulate transport phenomena in microfluidic devices with ferrofluid and fluorescent dye induced by a nonuniform magnetic field. The numerical results were validated by experimental data from our previous work, indicating a significant increase in mass transfer. The model shows a reasonable agreement with experimental data for the concentration distribution of both magnetic and nonmagnetic species. Magnetoconvective secondary flow enhances the transport of nonmagnetic fluorescent dye. A subsequent parametric analysis investigated the effect of the magnetic field strength and nanoparticle size on the mass transfer process. Mass transport of the fluorescent dye is enhanced with increasing field strength and size of magnetic particles.
Active Control of Droplet Formation Process in Microfluidics
Publisher: Springer New York
Date: 2012
Polyacrylonitrile-carbon Nanotube-polyacrylonitrile: A Versatile Robust Platform for Flexible Multifunctional Electronic Devices in Medical Applications
Publisher: Wiley
Date: 19-03-2019
Reliable addition of reagents into microfluidic droplets
Publisher: Springer Science and Business Media LLC
Date: 19-11-2009
Graphene-Oxide-Loaded Superparamagnetic Iron Oxide Nanoparticles for Ultrasensitive Electrocatalytic Detection of MicroRNA
Publisher: Wiley
Date: 27-06-2018
Analysis of capillary filling in nanochannels with electroviscous effects
Publisher: Springer Science and Business Media LLC
Date: 29-01-2009
Focused Flow Micropump Using Ultrasonic Flexural Plate Waves
Publisher: Springer Science and Business Media LLC
Date: 2000
Universal Electrochemical Synthesis of Mesoporous Chalcogenide Semiconductors: Mesoporous CdSe and CdTe Thin Films for Optoelectronic Applications
Publisher: Wiley
Date: 17-03-2021
Abstract: Here we report the soft‐template‐assisted electrochemical deposition of mesoporous semiconductors (CdSe and CdTe). The resulting mesoporous films are stoichiometrically equivalent and contain mesopores homogeneously distributed over the entire surface. To demonstrate the versatility of the method, two block copolymers with different molecular weights are used, yielding films with pores of either 9 or 18 nm diameter. As a proof of concept, the mesoporous CdSe film‐based photodetectors show a high sensitivity of 204 mW −1 cm 2 at 680 nm wavelength, which is at least two orders of magnitude more sensitive than the bulk counterpart. This work presents a new synthesis route for nanostructured semiconductors with optical band gaps active in the visible spectrum.
Core-shell microparticles: Generation approaches and applications
Publisher: Elsevier BV
Date: 12-2020
Magnetofluidic spreading in microchannels
Publisher: Springer Science and Business Media LLC
Date: 14-09-2012
Thermal mixing of two miscible fluids in a T-shaped microchannel
Publisher: AIP Publishing
Date: 10-2010
DOI: 10.1063/1.3496359
Abstract: In this paper, thermal mixing characteristics of two miscible fluids in a T-shaped microchannel are investigated theoretically, experimentally, and numerically. Thermal mixing processes in a T-shaped microchannel are ided into two zones, consisting of a T-junction and a mixing channel. An analytical two-dimensional model was first built to describe the heat transfer processes in the mixing channel. In the experiments, de-ionized water was employed as the working fluid. Laser induced fluorescence method was used to measure the fluid temperature field in the microchannel. Different combinations of flow rate ratios were studied to investigate the thermal mixing characteristics in the microchannel. At the T-junction, thermal diffusion is found to be dominant in this area due to the striation in the temperature contours. In the mixing channel, heat transfer processes are found to be controlled by thermal diffusion and convection. Measured temperature profiles at the T-junction and mixing channel are compared with analytical model and numerical simulation, respectively.
Avoiding Pre-Isolation Step in Exosome Analysis: Direct Isolation and Sensitive Detection of Exosomes Using Gold-Loaded Nanoporous Ferric Oxide Nanozymes
Publisher: American Chemical Society (ACS)
Date: 08-02-2019
DOI: 10.1021/ACS.ANALCHEM.8B03619
Abstract: Most of the current exosome-analysis strategies are time-consuming and largely dependent on commercial extraction kit-based preisolation step, which requires extensive s le manipulations, costly isolation kits, reagents, tedious procedures, and sophisticated equipment and is prone to bias/artifacts. Herein we introduce a simple method for direct isolation and subsequent detection of a specific population of exosomes using an engineered superparamagnetic material with multifunctional properties, namely, gold-loaded ferric oxide nanocubes (Au-NPFe
Universal Electrochemical Synthesis of Mesoporous Chalcogenide Semiconductors: Mesoporous CdSe and CdTe Thin Films for Optoelectronic Applications
Publisher: Wiley
Date: 17-03-2021
Abstract: Here we report the soft‐template‐assisted electrochemical deposition of mesoporous semiconductors (CdSe and CdTe). The resulting mesoporous films are stoichiometrically equivalent and contain mesopores homogeneously distributed over the entire surface. To demonstrate the versatility of the method, two block copolymers with different molecular weights are used, yielding films with pores of either 9 or 18 nm diameter. As a proof of concept, the mesoporous CdSe film‐based photodetectors show a high sensitivity of 204 mW −1 cm 2 at 680 nm wavelength, which is at least two orders of magnitude more sensitive than the bulk counterpart. This work presents a new synthesis route for nanostructured semiconductors with optical band gaps active in the visible spectrum.
Toward the commercialization of optofluidics
Publisher: Springer Science and Business Media LLC
Date: 08-2017
Carbon dots functionalized by organosilane with double-sided anchoring for nanomolar Hg2+ detection
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.JCIS.2014.09.013
Abstract: Surface functional groups on carbon dots (CDs) play a critical role in defining their photoluminescence properties and functionalities. A new kind of organosilane-functionalized CDs (OS-CDs) were formed by a low temperature (150°C) solvothermal synthesis of citric acid in N-(β-aminoethyl)-γ-aminopropylmethyl-dimethoxysilane (AEAPMS). Uniquely, the as-synthesized OS-CDs have dual long chain functional groups with both NH2 and Si(OCH3)3 as terminal moieties. Double sided anchoring of AEAPMS on CDs occurs, facilitated by the water produced (and confined at the interface between CDs and solvent) when citric acid condenses into the carbon core. The resultant OS-CDs are multi-solvent dispersible, and more significantly, they exhibit excellent selectivity and sensitivity to Hg(2+) with a linear detection range of 0-50 nM and detection limit of 1.35 nM. The sensitivity and selectivity to Hg(2+) is preserved in highly complex fluids with a detection limit of 1.7 nM in spiked 1 M NaCl solution and a detection limit of 50 nM in municipal wastewater effluent. The results show that the OS-CDs synthesised by the solvothermal method in AEAPMS may be used as an effective Hg(2+) sensor in practical situations.
Opto-electronic coupling in semiconductors: towards ultrasensitive pressure sensing
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TC00229A
Abstract: A novel concept of opto-electronic coupling in semiconductor heterojunctions for pressure sensing is proposed. By using non-uniform illumination of visible light coupling with tuning current, performance of the pressure sensor is enormously enhanced.
Programmable manipulation of a droplet in a planar microchannel
Publisher: ASMEDC
Date: 2008
Abstract: Programmable thermocapillary manipulation of liquid droplet in a planar microchannel has been carried out by both theoretical modeling and experimental characterization in this paper. The driving temperature gradients are provided by four micro-heaters at the channel boundaries. In the modeling, the temperature distributions corresponding to both transient and periodic actuation are calculated, and are coupled to the droplet motion through the surface tensions which drives the droplet to move inside the channel. The droplet trajectories and final positions are simulted, and compared with the experimental results, in which a silicon oil droplet was actuated inside a 10 mm×10 mm planar channel with four heater fabricated on the substrate plate. The results show that the droplet can be positioned anywhere in the channel, determined by a heating code related to the heating strengths. Qualitative agreement between the modeling results and experimental data, in terms of temperature distributions, droplet positions and trajectories, has been obtained.
Visualizing the transient electroosmotic flow and measuring the zeta potential of microchannels with a micro-PIV technique
Publisher: AIP Publishing
Date: 11-01-2006
DOI: 10.1063/1.2162533
Abstract: We have demonstrated a transient micro particle image velocimetry (micro-PIV) technique to measure the temporal development of electroosmotic flow in microchannels. Synchronization of different trigger signals for the laser, the CCD camera, and the high-voltage switch makes this measurement possible with a conventional micro-PIV setup. Using the transient micro-PIV technique, we have further proposed a method on the basis of inertial decoupling between the particle electrophoretic motion and the fluid electroosmotic flow to determine the electrophoretic component in the particle velocity and the zeta potential of the channel wall. It is shown that using the measured zeta potentials, the theoretical predictions agree well with the transient response of the electroosmotic velocities measured in this work.
An Electrochemical Method for the Detection of Disease-Specific Exosomes
Publisher: Wiley
Date: 30-08-2017
A micro optofluidic lens with short focal length
Publisher: IOP Publishing
Date: 13-07-2009
Liquid marbles as biochemical reactors for the polymerase chain reaction
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9LC00676A
Abstract: Liquid marbles can serve as a biochemical reactor for the polymerase chain reaction, eliminating the conventional single use plastic reaction vial.
Wet oxidation of 3C-SiC on Si for MEMS processing and use in harsh environments: Effects of the film thicknesses, crystalline orientations, and growth temperatures
Publisher: Elsevier BV
Date: 2021
Effects of obstacles on inertial focusing and separation in sinusoidal channels: An experimental and numerical study
Publisher: Elsevier BV
Date: 07-2023
Lab-on-a-chip for rapid electrochemical detection of nerve agent Sarin
Publisher: Springer Science and Business Media LLC
Date: 28-11-2013
DOI: 10.1007/S10544-013-9830-4
Abstract: This paper reports a lab-on-a-chip for the detection of Sarin nerve agent based on rapid electrochemical detection. The chemical warfare agent Sarin (C₄H₁₀FO₂P, O-isopropyl methylphosphonofluoridate) is a highly toxic organophosphate that induces rapid respiratory depression, seizures and death within minutes of inhalation. As purified Sarin is colourless, odourless, water soluble and a easily disseminated nerve agent, it has been used as a weapon in terrorist or military attacks. To ascertain whether potable water supplies have been adulterated with this extremely potent poison, an inexpensive, sensitive and easy to use portable test kit would be of interest to first responders investigating such attacks. We report here an erometric-based approach for detecting trace amounts of Sarin in water s les using a screen-printed electrode (SPE) integrated in a microfluidic chip. Enzymatic inhibition was obtained by exposing the immobilised biosensor in the microfluidic platform to Sarin in water s les. With the aid of cobalt phthalocyanine modified SPE, the device could detect Sarin at part-per-billion levels with concentration as low as 1 nM. The detection method reported here represents a significant improvement over the authors'previous optical-based detection method.
Polymer-based device for efficient mixing of viscoelastic fluids
Publisher: AIP Publishing
Date: 29-05-2006
DOI: 10.1063/1.2206682
Abstract: We demonstrated rapid mixing of viscoelastic fluids in microchannels constructed based on polymethyl methacrylate. Viscoelastic mixing without diffusion was achieved with an effective mixing length of less than 5mm and a relatively fast flow rate. With an abrupt contraction microgeometry (8:1 contraction ratio), we mixed two different viscoelastic fluids experimentally at very low Reynolds numbers, but enormous Peclet and elasticity numbers. This special geometrical configuration triggers flow instability, leading to turbulent and efficient mixing. This flow regime has negligible inertia effects but significant elastic effects.
Inertial particle separation by differential equilibrium positions in a symmetrical serpentine micro-channel
Publisher: Springer Science and Business Media LLC
Date: 31-03-2014
DOI: 10.1038/SREP04527
The three-phase contact line shape and eccentricity effect of anisotropic wetting on hydrophobic surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2SM26963E
An investigation on the mechanism of droplet formation in a microfluidic T-junction
Publisher: Springer Science and Business Media LLC
Date: 29-01-2011
A digital micro magnetofluidic platform for lab-on-a-chip applications
Publisher: ASME International
Date: 02-2013
DOI: 10.1115/1.4023443
Abstract: This paper reports the design and investigation of a digital micro magnetofluidic platform for lab-on-a-chip applications. The platform allows a ferrofluid droplet to be driven along a preprogrammed path. The platform consists of a programmable x-y-positioning stage, a permanent magnet and a glass plate coated with a thin layer of Teflon. First, the actuation of a stand-alone water-based ferrofluid droplet was investigated. Circular, rectangular, triangular and number-eight-shape trajectories were tested and analyzed. The speed of the droplet is evaluated from the position data of the black ferrofluid using a customized MATLAB program. The results show that better positioning accuracy and steady movement can be achieved with smooth trajectories. Next, the ferrofluid droplet as the driving engine for a cargo of other diamagnetic liquid droplets is demonstrated. The characteristics of different cargo volumes are investigated. Due to the liquid/liquid cohesion, a large cargo of five times the volume of a 3-μL ferrofluid droplet can be transported. If the cargo is larger than the driving ferrofluid droplet, the liquid system forms a long trail that faithfully follows the preprogrammed path. Various mixing experiments were carried out. The effectiveness of mixing in this system is demonstrated with a titration test as well as a chemiluminescence assay. The platform shows a robust, simple and flexible concept for implementing a complex analysis protocol with multiple reaction steps.
Development of a peristaltic pump in printed circuit boards
Publisher: Brill
Date: 04-2005
A laser-micromachined polymeric membraneless fuel cell
Publisher: IOP Publishing
Date: 26-04-2007
Investigation of viscoelastic focusing of particles and cells in a zigzag microchannel
Publisher: Wiley
Date: 02-09-2021
Abstract: Microfluidic particle focusing has been a vital prerequisite step in s le preparation for downstream particle separation, counting, detection, or analysis, and has attracted broad applications in biomedical and chemical areas. Besides all the active and passive focusing methods in Newtonian fluids, particle focusing in viscoelastic fluids has been attracting increasing interest because of its advantages induced by intrinsic fluid property. However, to achieve a well‐defined focusing position, there is a need to extend channel lengths when focusing micrometer‐sized or sub‐microsized particles, which would result in the size increase of the microfluidic devices. This work investigated the sheathless viscoelastic focusing of particles and cells in a zigzag microfluidic channel. Benefit from the zigzag structure of the channel, the channel length and the footprint of the device can be reduced without sacrificing the focusing performance. In this work, the viscoelastic focusing, including the focusing of 10 μm polystyrene particles, 5 μm polystyrene particles, 5 μm magnetic particles, white blood cells (WBCs), red blood cells (RBCs), and cancer cells, were all demonstrated. Moreover, magnetophoretic separation of magnetic and nonmagnetic particles after viscoelastic pre‐focusing was shown. This focusing technique has the potential to be used in a range of biomedical applications.
Acoustically induced bubbles in a microfluidic channel for mixing enhancement
Publisher: Springer Science and Business Media LLC
Date: 25-10-2008
Thermoresistive properties of p-type 3C–SiC nanoscale thin films for high-temperature MEMS thermal-based sensors
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA20289B
Abstract: We report for the first time the thermoresistive property of p-type single crystalline 3C–SiC (p-3C–SiC), which was epitaxially grown on a silicon (Si) wafer, and then transferred to a glass substrate using a Focused Ion Beam (FIB) technique.
Time-dependent model of mixed electroosmotic/pressure-driven three immiscible fluids in a rectangular microchannel
Publisher: Elsevier BV
Date: 2010
Nanoarchitectured peroxidase-mimetic nanozymes: mesoporous nanocrystalline α- or γ-iron oxide?
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TB00989B
Abstract: Next-generation nanozyme based biosensing: mesoporous nanocrystalline α- or γ-iron oxide?
Fundamentals of differential particle inertial focusing in symmetric sinusoidal microchannels
Publisher: American Chemical Society (ACS)
Date: 23-01-2019
DOI: 10.1021/ACS.ANALCHEM.8B05712
Abstract: Focusing and separation of particles such as cells at high throughput is extremely attractive for biomedical applications. Particle manipulation based on inertial effects requires a high flow speed and thus is well-suited to high-throughput applications. Recently, inertial focusing and separation using curvilinear microchannels has been attracting a great amount of interest because of the linear structure for parallelization, small device footprint, superior particle-focusing performance, and easy implementation of particle separation. However, the curvature directions of these microchannels alternate, leading to variations in both the magnitude and direction of the induced secondary flow. Accumulation of this variation along the channel causes unpredictable behaviors of particles. This paper systematically investigates the inertial-focusing phenomenon in low-aspect-ratio symmetric sinusoidal channels. First, we comprehensively studied the effects of parameters such as viscosity, flow conditions, particle size, and geometric dimensions of the microchannel on differential particle focusing. We found that particle inertial focusing is generally independent of fluid kinematic viscosity but highly dependent on particle size, flow conditions, and channel dimensions. Next, we derived an explicit scaling factor and included all four dimensionless parameters (particle-blockage ratio, curvature ratio, Dean number, and channel aspect ratio) in a single operational map to illustrate the particle-focusing patterns. Finally, we proposed a rational guideline to intuitively instruct the design of channel dimensions for separation of a given particle mixture.
A Wearable, Bending-Insensitive Respiration Sensor Using Highly Oriented Carbon Nanotube Film
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-03-2021
Engineering Micropatterned Surfaces for Controlling the Evaporation Process of Sessile Droplets
Publisher: MDPI AG
Date: 19-05-2020
DOI: 10.3390/TECHNOLOGIES8020029
Abstract: Controlling the evaporation process of a droplet is of the utmost importance for a number of technologies. Also, along with the advances of microfabrication, micropatterned surfaces have emerged as an important technology platform to tune the wettability and other surface properties of various fundamental and applied applications. Among the geometrical parameters of these micropatterns, it is of great interest to investigate whether the arrangement of the patterns would affect the evaporation process of a sessile liquid droplet. To address this question, we fabricated four microhole arrays with different arrangements, quantified by the parameter of “eccentricity”. The results suggested that, compared to smooth substrates, the evaporation mode was not only affected by engineering the microhole arrays, but also by the eccentricity of these micropatterns. The values of contact angle hysteresis (CAH) were used to quantify and test this hypothesis. The CAH could partially explain the different evaporation modes observed on the microhole arrays with zero and non-zero values of eccentricity. That is, on microhole arrays with zero eccentricity, CAH of water droplets was comparatively low (less than 20 ° ). Consistently, during the evaporation, around 60% of the life span of the droplet was in the mixed evaporation mode. Increasing the eccentricity of the microhole arrays increases the values of CAH to above 20 ° . Unlike the increasing trend of CAH, the evaporation modes of sessile droplets on the microhole array with non-zero values of eccentricity were almost similar. Over 75% of the life span of droplets on these surfaces was in constant contact line (CCL) mode. Our findings play a significant role in any technology platform containing micropatterned surfaces, where controlling the evaporation mode is desirable.
Effects of magnetic nanoparticles on mixing in droplet-based microfluidics
Publisher: AIP Publishing
Date: 03-2019
DOI: 10.1063/1.5086867
Abstract: High-throughput, rapid and homogeneous mixing of microdroplets in a small length scale such as that in a microchannel is of great importance for lab-on-a-chip applications. Various techniques for mixing enhancement in microfluidics have been extensively reported in the literature. One of these techniques is the mixing enhancement with magnetofluidics using ferrofluid, a liquid with dispersed magnetic nanoparticles. However, a systematic study exploring the mixing process of ferrofluid and its influencing parameters is lacking. This study numerically examines the effect of key parameters including magnetic field, mean velocity, and size of a microdroplet on the mixing process. A microfluidic double T-junction with droplets in merging regime is considered. One of the dispersed phases is a ferrofluid containing paramagnetic nanoparticles, while the other carried neutral species. Under an applied magnetic field, the ferrofluid experiences a magnetic force that in turn induces a secondary bulk flow called magnetoconvection. The combination of the induced magnetoconvection and shear-driven circulating flow within a moving droplet improves the mixing efficiency remarkably. Mixing enhancement is maximized for a specific ratio between the magnetic force and the shear force. The dominance of either force would deteriorate the mixing performance. On the other hand, using a magnetic force and a shear force with comparable order of magnitude leads to an effective manipulation of vortices inside the droplet and subsequently causes an optimized particle distribution over the entire droplet. Furthermore, the smaller the droplets, the better the mixing.
Micromachines: 5000th Publications Milestone
Publisher: MDPI AG
Date: 17-12-2021
DOI: 10.3390/MI12121573
Abstract: Micromachines has achieved a major milestone this year [...]
A reliable method for bonding polydimethylsiloxane (PDMS) to polymethylmethacrylate (PMMA) and its application in micropumps
Publisher: Elsevier BV
Date: 11-2010
Adhesive-based liquid metal radio-frequency microcoil for magnetic resonance relaxometry measurement
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1LC20853E
Abstract: This paper reports the fabrication and characterization of an adhesive-based liquid-metal microcoil for magnetic resonance relaxometry (MRR). Conventionally, microcoils are fabricated by various techniques such as electroplating, microcontact printing and focused ion beam milling. These techniques require considerable fabrication efforts and incur high cost. In this paper, we demonstrate a novel technique to fabricate three-dimensional multilayer liquid-metal microcoils together with the microfluidic network by lamination of dry adhesive sheets. One of the unique features of the adhesive-based technique is that the detachable s le chamber can be disposed after each experiment and the microcoil can be reused without cross-contamination multiple times. The integrated microcoil has a low direct-current (DC) resistance of 0.3 Ω and a relatively high inductance of 67.5 nH leading to a high quality factor of approximately 30 at 21.65 MHz. The microcoil was characterized for ∼0.5 T proton MRR measurements. The optimal pulse duration, litude, and frequency for the 90° pulse were 131 μs, -30 dB (1.56 W) and 21.6553 MHz, respectively. In addition, we used the liquid-metal microcoil to perform a parametric study on the transverse relaxation rate of human red blood cells at different hematocrit levels. The transverse relaxation rate increases quadratically with the hematocrit level. The results from the liquid-metal microcoil were verified by measurements with a conventional solenoid coil.
Fabrication and characterization of core–shell microparticles containing an aqueous core
Publisher: Springer Science and Business Media LLC
Date: 10-11-2022
DOI: 10.1007/S10544-022-00637-9
Abstract: Core–shell microparticles containing an aqueous core have demonstrated their value for microencapsulation and drug delivery systems. The most important step in generating these uniquely structured microparticles is the formation of droplets and double emulsion. The droplet generator must meet the performance and reliability requirements, including accurate size control with tunability and monodispersity. Herein, we present a facile technique to generate surfactant-free core–shell droplets with an aqueous core in a microfluidic device. We demonstrate that the geometry of the core–shell droplets can be precisely adjusted by the flow rates of the droplet components. As the shell is polymerized after the formation of the core–shell droplets, the resulting solid microparticles ensure the encapsulation of the aqueous core and prevent undesired release. We then study experimentally and theoretically the behaviour of resultant microparticles under heating and compression. The microparticles demonstrate excellent stability under both thermal and mechanical loads. We show that the rupture force can be quantitatively predicted from the shell thickness relative to the outer shell radius. Experimental results and theoretical predictions confirm that the rupture force scales directly with the shell thickness. Graphical abstract
Analytical model of plug flow in microchannels
Publisher: IEEE
Date: 02-2011
Identification of coherent patterns in gene expression data using an efficient biclustering algorithm and parallel coordinate visualization
Publisher: Springer Science and Business Media LLC
Date: 23-04-2008
Abstract: The DNA microarray technology allows the measurement of expression levels of thousands of genes under tens/hundreds of different conditions. In microarray data, genes with similar functions usually co-express under certain conditions only [1]. Thus, biclustering which clusters genes and conditions simultaneously is preferred over the traditional clustering technique in discovering these coherent genes. Various biclustering algorithms have been developed using different bicluster formulations. Unfortunately, many useful formulations result in NP-complete problems. In this article, we investigate an efficient method for identifying a popular type of biclusters called additive model. Furthermore, parallel coordinate (PC) plots are used for bicluster visualization and analysis. We develop a novel and efficient biclustering algorithm which can be regarded as a greedy version of an existing algorithm known as pCluster algorithm. By relaxing the constraint in homogeneity, the proposed algorithm has polynomial-time complexity in the worst case instead of exponential-time complexity as in the pCluster algorithm. Experiments on artificial datasets verify that our algorithm can identify both additive-related and multiplicative-related biclusters in the presence of overlap and noise. Biologically significant biclusters have been validated on the yeast cell-cycle expression dataset using Gene Ontology annotations. Comparative study shows that the proposed approach outperforms several existing biclustering algorithms. We also provide an interactive exploratory tool based on PC plot visualization for determining the parameters of our biclustering algorithm. We have proposed a novel biclustering algorithm which works with PC plots for an interactive exploratory analysis of gene expression data. Experiments show that the biclustering algorithm is efficient and is capable of detecting co-regulated genes. The interactive analysis enables an optimum parameter determination in the biclustering algorithm so as to achieve the best result. In future, we will modify the proposed algorithm for other bicluster models such as the coherent evolution model.
Ferrofluidic plug flow heat transfer enhancement
Publisher: International Information and Engineering Technology Association
Date: 11-2018
Fabrication of Nanochannels on Polymer Thin Film
Publisher: ASMEDC
Date: 2009
Abstract: Recent advances in nanotechnology allow the fabrication of structures down to the nanometer range. Various theoretical and experimental studies on the characteristics of fluid in nanochannels have been carried out in recent years. The results show that transport phenomena in nanoscale promise a wide range of applications in biological and chemical analysis. Practical applications require fabrication of nanochannels with a short production time and at a low cost. Polymer is considered as a suitable material for mass production of nanochannels due to the wide range of properties available, as well as the low cost of material and fabrication process. This paper reports the fabrication of planar nanochannels using hot embossing and thermal bonding technique on a polymer thin film. The mold for hot embossing was fabricated on a silicon wafer using photolithography and Reactive Ion Etching (RIE). Polymethylmethacrylate (PMMA) thin film with a thickness of 250 μm was used as the base material to emboss the nanochannels from the silicon mold. Temperature and pressure were controlled and recorded continuously during the embossing process. The channels then were examined by Atomic Force Microscope (AFM) in tapping mode to verify the width and the depth of the channel. Next, another piece of PMMA thin film was bonded to the first piece by thermal bonding process to make closed nanochannels. Temperature and pressure during the bonding process were controlled and recorded. Access to the channels was made on the thin film by a laser cutter before embossing. The results showed that open planar channels with the depth down to 30nm can be fabricated on PMMA thin film with a process time less than 30 minutes. Width and depth of the channels agree well with appropriate dimensions on the mold. Bonding can be achieved within 40 minutes. Closed planar channels with the depth of 300nm were fabricated successfully by a combination of embossing and thermal bonding processes. This project demonstrates the possibility of fabricating nanochannels with low cost and short processing time using polymer material. The processes are suitable not only for nanochannels but also for more complicated nanostructures. The presented technique allows the fabrication of nanodevices with various designs.
A Generalized Analytical Model for Joule Heating of Segmented Wires
Publisher: ASME International
Date: 30-03-2018
DOI: 10.1115/1.4038829
Abstract: This paper presents an analytical solution for the Joule heating problem of a segmented wire made of two materials with different properties and suspended as a bridge across two fixed ends. The paper first establishes the one-dimensional (1D) governing equations of the steady-state temperature distribution along the wire with the consideration of heat conduction and free-heat convection phenomena. The temperature coefficient of resistance of the constructing materials and the dimension of the each segmented wires were also taken into account to obtain analytical solution of the temperature. COMSOL numerical solutions were also obtained for initial validation. Experimental studies were carried out using copper and nichrome wires, where the temperature distribution was monitored using an IR thermal camera. The data showed a good agreement between experimental data and the analytical data, validating our model for the design and development of thermal sensors based on multisegmented structures.
Multiscale and Multimaterial Fabrication: The Challenge Ahead
Publisher: MDPI AG
Date: 10-2016
DOI: 10.3390/MI7100178
Magnetowetting and Sliding Motion of a Sessile Ferrofluid Droplet in the Presence of a Permanent Magnet
Publisher: American Chemical Society (ACS)
Date: 07-07-2010
DOI: 10.1021/LA101474E
Abstract: Motion of a droplet on a planar surface has applications in droplet-based lab on a chip technology. This paper reports the experimental results of the shape, contact angles, and motion of ferrofluid droplets driven by a permanent magnet on a planar homogeneous surface. The water-based ferrofluid in use is a colloidal suspension of single-domain magnetic nanoparticles. The effect of the magnetic field on the apparent contact angle of the ferrofluid droplet was first investigated. The results show that an increasing magnetic flux decreases the apparent contact angle of a sessile ferrofluid droplet. Next, the dynamic contact angle was investigated by observing the shape and the motion of a sessile ferrofluid droplet. The advancing and receding contact angles of the moving ferrofluid were measured at different moving speeds and magnetic field strengths. The measured contact angles were used to estimate the magnitude of the forces involved in the sliding motion. Scaling analysis was carried out to derive the critical velocity, beyond which the droplet is not able to catch up with the moving magnet.
A Numerical Investigation of Thermally Mediated Droplet Formation in a T-Junction
Publisher: ASMEDC
Date: 2009
Abstract: The present article presents a numerical investigation on the effect of thermal forcing for droplet formation in a T-junction. Thermal forcing, generated by a heater embedded into the channel wall, induces a non-uniform temperature field which results in the variation the fluids’ properties and affects the droplet formation process in a desirable manner. In the present article, droplet formation process is posed as an incompressible immiscible two-phase flow problem with the motion of the two-phases strongly coupled via the related interfacial conditions. It is governed by the three-dimensional Navier-Stokes and the energy equations. The interface is captured with a narrow-band particle level-set method. Solutions are obtained using a finite volume method on a staggered mesh. The numerical model is validated against droplet formation in a cross junction. With the formation of water droplet in oil within the squeezing formation regime as a case study, the physics underlying droplet formation process in a T-junction affected by a thermal forcing is investigated. The combined effect of variations in both viscosities and surface tension result in a larger droplet. It is believed that the behavior of fluids system under an imposed thermal forcing depends strongly on the characteristics of temperature dependent viscosities and surface tension.
Microdroplet formation of water and nanofluids in heat-induced microfluidic T-junction
Publisher: Springer Science and Business Media LLC
Date: 02-07-2008
Three-dimensional visualization and analysis of flowing droplets in microchannels using real-time quantitative phase microscopy
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0LC00917B
Abstract: We present real-time quantitative phase microscopy (RT-QPM) that can be used for on-chip three-dimensional visualization of droplets and high-throughput quantitative molecular measurement via real-time extraction of s le-induced phase variation.
Sessile Liquid Marbles with Embedded Hydrogels as Bioreactors for Three‐Dimensional Cell Culture
Publisher: Wiley
Date: 12-01-2021
Microfluidic Gut-on-a-Chip: Fundamentals and Challenges
Publisher: MDPI AG
Date: 13-01-2023
DOI: 10.3390/BIOS13010136
Abstract: The human gut is responsible for food digestion and absorption. Recently, growing evidence has shown its vital role in the proper functioning of other organs. Advances in microfluidic technologies have made a significant impact on the biomedical field. Specifically, organ-on-a-chip technology (OoC), which has become a popular substitute for animal models, is capable of imitating complex systems in vitro and has been used to study pathology and pharmacology. Over the past decade, reviews published focused more on the applications and prospects of gut-on-a-chip (GOC) technology, but the challenges and solutions to these limitations were often overlooked. In this review, we cover the physiology of the human gut and review the engineering approaches of GOC. Fundamentals of GOC models including materials and fabrication, cell types, stimuli and gut microbiota are thoroughly reviewed. We discuss the present GOC model applications, challenges, possible solutions and prospects for the GOC models and technology.
Laser induced self-N-doped porous graphene as an electrochemical biosensor for femtomolar miRNA detection
Publisher: Elsevier BV
Date: 08-2020
Snapshot of an early Paleoproterozoic ecosystem: Two diverse microfossil communities from the Turee Creek Group, Western Australia.
Publisher: Wiley
Date: 09-08-2018
DOI: 10.1111/GBI.12304
Abstract: Eighteen microfossil morphotypes from two distinct facies of black chert from a deep-water setting of the c. 2.4 Ga Turee Creek Group, Western Australia, are reported here. A primarily in situ, deep-water benthic community preserved in nodular black chert occurs as a tangled network of a variety of long filamentous microfossils, unicells of one size distribution and fine filamentous rosettes, together with relatively large spherical aggregates of cells interpreted as in-fallen, likely planktonic, forms. Bedded black cherts, in contrast, preserve microfossils primarily within, but also between, rounded clasts of organic material that are coated by thin, convoluted carbonaceous films interpreted as preserved extracellular polymeric substance (EPS). Microfossils preserved within the clasts include a wide range of unicells, both much smaller and larger than those in the nodular black chert, along with relatively short, often degraded filaments, four types of star-shaped rosettes and umbrella-like rosettes. Large, complexly branching filamentous microfossils are found between the clasts. The grainstone clasts in the bedded black chert are interpreted as transported from shallower water, and the contained microfossils thus likely represent a phototrophic community. Combined, the two black chert facies provide a snapshot of a microbial ecosystem spanning shallow to deeper-water environments, and an insight into the ersity of life present during the rise in atmospheric oxygen. The preserved microfossils include two new, distinct morphologies previously unknown from the geological record, as well as a number of microfossils from the bedded black chert that are morphologically similar to-but 400-500 Ma older than-type specimens from the c. 1.88 Ga Gunflint Iron Formation. Thus, the Turee Creek Group microfossil assemblage creates a substantial reference point in the sparse fossil record of the earliest Paleoproterozoic and demonstrates that microbial life ersified quite rapidly after the end of the Archean.
Dynamic Behaviours of Monodisperse Double Emulsion Formation in a Tri-Axial Capillary Device
Publisher: MDPI AG
Date: 31-10-2022
DOI: 10.3390/MI13111877
Abstract: We investigated experimentally, analytically, and numerically the formation process of double emulsion formations under a dripping regime in a tri-axial co-flow capillary device. The results show that mismatches of core and shell droplets under a given flow condition can be captured both experimentally and numerically. We propose a semi-analytical model using the match ratio between the pinch-off length of the shell droplet and the product of the core growth rate and its pinch-off time. The mismatch issue can be avoided if the match ratio is lower than unity. We considered a model with the wall effect to predict the size of the matched double emulsion. The model shows slight deviations with experimental data if the Reynolds number of the continuous phase is lower than 0.06 but asymptotically approaches good agreement if the Reynolds number increases from 0.06 to 0.14. The numerical simulation generally agrees with the experiments under various flow conditions.
Sample flow switching technique based on combined effect of hydrodynamic and electroosmosis
Publisher: ASMEDC
Date: 2010
Abstract: This paper presents theoretical and experimental investigations on valveless microfluidic switch using the coupled effect of hydrodynamics and electroosmosis. In the experiment, two sheath streams (aqueous NaCl and glycerol) and the s le stream (silicon oil) are introduced by syringe pumps to flow side by side in a straight rectangular microchannel. External electric fields are applied on the two sheath streams. Under the constant inlet volumetric flowrates, the s le stream is delivered to the desired outlet ports using electroosmotic effect. The liquid fractions of sheath streams are measured using fluorescence imaging technique. The results indicate that under suitable cooperation of electric fields, the s le stream can be delivered to the desired outlet ports.
Naked-eye and electrochemical detection of isothermally amplified HOTAIR long non-coding RNA
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7AN02109G
Abstract: A naked-eye, colorimetric and electrochemical detection of HOTAIR long non-coding RNA has been demonstrated.
High-temperature tolerance of the piezoresistive effect in p-4H-SiC for harsh environment sensing
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8TC03094D
Abstract: 4H-silicon carbide based sensors are promising candidates for replacing prevalent silicon-based counterparts in harsh environments owing to their superior chemical inertness, high stability and reliability.
Advanced liquid biopsy technologies for circulating biomarker detection
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TB01490J
Abstract: In this review, we have summarised the biogenesis, biological significance, isolation and detection technologies of four widely known circulating biomarkers namely circulating tumour cells, circulating tumor specific DNA, microRNA, and exosomes.
Synthesis of nanoporous poly-melamine-formaldehyde (PMF) based on Schiff base chemistry as a highly efficient adsorbent
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8AN01623B
Abstract: This study proposes the construction of nanoporous poly-melamine-formaldehyde through the Schiff base condensation of paraformaldehyde and melamine.
Manipulation of a floating liquid marble using dielectrophoresis
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8LC01057A
Abstract: A liquid marble is a microliter-sized droplet coated with hydrophobic powder.
Tunable micro-optofluidic prism based on liquid-core liquid-cladding configuration
Publisher: Optica Publishing Group
Date: 25-01-2010
DOI: 10.1364/OL.35.000327
Stretching induces overexpression of RhoA and Rac1 GTPases in breast cancer cells
Publisher: Wiley
Date: 05-12-2019
Electrospray propelled by ionic wind in a bipolar system for direct delivery of charge reduced nanoparticles
Publisher: IOP Publishing
Date: 15-04-2021
DOI: 10.35848/1882-0786/ABF36B
Abstract: We present a conceptual design to generate and deliver nanoparticles in one unique system based on electrohydrodynamic atomisation (EHDA) without the restriction of the collector. The present EHDA bipolar configuration consists of a capillary nozzle and a pin, both act as emitters and as the reference electrodes of each other. Under an applied voltage, the capillary nozzle sprays droplets while the pin generates ion wind via corona discharge. During spraying process, droplets’ charge is significantly reduced by interacting with counter ions and propelled away from the electrodes by the momentum of ion winds accumulated from corona discharge. Thus, the present technique can yield promising applications in effective respiratory delivery of nanomedicine.
Capillary Filling in Nanochannels
Publisher: ASMEDC
Date: 2009
Abstract: Capillary filling is the key phenomenon in planar chromatography techniques such as paper chromatography and thin layer chromatography. While capillary filling in channels of micrometers scale are experimentally verified that obeys well to Washburn’s law, there is evident show that the speed of capillary filling in nanochannels is noticeable lower than described by Washburn’s formula. This paper describes a model for capillary filling phenomenon in nanochannel. Experiments on the filling of electrolytic and nonelectrolytic solutions in polymeric nanochannels were carried out. The filling processes were observed and recorded. Filling distances were measured, from which filling speeds were derived. Formation of air bubbles was also observed with some channel’s geometry. A mathematical model to calculate the electroviscous effect was established. This model shows that contribution of electroviscous effect in the reduction of filling speed is small. This result also agrees well with other previous theoretical works on the electroviscous effect. That means beside electroviscous effect, there are other phenomena that contribute in the reduction of capillary filling speed in nanochannel, such as air bubbles formation. Those phenomena need to be described qualitatively and quantitatively in order to understand more on the capillary filling in nanochannel.
Modeling and Characterization of Micro Optofluidic Lenses With Short Focal Length
Publisher: ASMEDC
Date: 2009
Abstract: In this paper, fluidic models of liquid-core liquid-cladding lens formed in a circular chamber are reported. The models cover two cases: the circular chamber is symmetrical and asymmetrical to the channel axis. Experiments were also carried out to verify our models. The results agree well with the theoretical analysis. The test device with a circular lens chamber with 1-mm diameter and 100-μm height was fabricated in PDMS. The design of a circular chamber is demonstrated to develop a perfect arc shape of the lens interface, which can be mathematically pre-defined. The focusing abilities of lens formed in these two different geometries are compared. We found that the asymmetrical design, in which the channel is offseted from the axis of chamber, can develop a lens with shorter focal length. This design has an important significance for on-chip focusing.
Passive and Active Micromixers
Publisher: Wiley
Date: 18-02-2009
Design, fabrication and characterization of drug delivery systems based on lab-on-a-chip technology
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.ADDR.2013.05.008
Abstract: Lab-on-a-chip technology is an emerging field evolving from the recent advances of micro- and nanotechnologies. The technology allows the integration of various components into a single microdevice. Microfluidics, the science and engineering of fluid flow in microscale, is the enabling underlying concept for lab-on-a-chip technology. The present paper reviews the design, fabrication and characterization of drug delivery systems based on this amazing technology. The systems are categorized and discussed according to the scales at which the drug is administered. Starting with the fundamentals on scaling laws of mass transfer and basic fabrication techniques, the paper reviews and discusses drug delivery devices for cellular, tissue and organism levels. At the cellular level, a concentration gradient generator integrated with a cell culture platform is the main drug delivery scheme of interest. At the tissue level, the synthesis of smart particles as drug carriers using lab-on-a-chip technology is the main focus of recent developments. At the organism level, microneedles and implantable devices with fluid-handling components are the main drug delivery systems. For drug delivery to a small organism that can fit into a microchip, devices similar to those of cellular level can be used.
Controllable droplet generation at a microfluidic T-junction using AC electric field
Publisher: Springer Science and Business Media LLC
Date: 03-2020
Liquid metal microcoils for sensing and actuation in lab-on-a-chip applications
Publisher: Springer Science and Business Media LLC
Date: 26-09-2015
Microfluidic switch based on combined effect of hydrodynamics and electroosmosis
Publisher: Springer Science and Business Media LLC
Date: 09-11-2010
Inertial Microfluidic Purification of Floating Cancer Cells for Drug Screening and Three-Dimensional Tumor Models
Publisher: American Chemical Society (ACS)
Date: 25-06-2020
Quantum dot-based sensitive detection of disease specific exosome in serum
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7AN00672A
Abstract: We report a stripping voltammetric immunoassay for the electrochemical detection of disease specific exosomes using quantum dots as electrochemical signal lifiers.
Mixing in microchannels based on hydrodynamic focusing and time-interleaved segmentation: Modelling and experiment
Publisher: Royal Society of Chemistry (RSC)
Date: 2005
DOI: 10.1039/B507548C
Abstract: This paper theoretically and experimentally investigates a micromixer based on combined hydrodynamic focusing and time-interleaved segmentation. Both hydrodynamic focusing and time-interleaved segmentation are used in the present study to reduce mixing path, to shorten mixing time, and to enhance mixing quality. While hydrodynamic focusing reduces the transversal mixing path, time-interleaved sequential segmentation shortens the axial mixing path. With the same viscosity in the different streams, the focused width can be adjusted by the flow rate ratio. The axial mixing path or the segment length can be controlled by the switching frequency and the mean velocity of the flow. Mixing ratio can be controlled by both flow rate ratio and pulse width modulation of the switching signal. This paper first presents a time-dependent two-dimensional analytical model for the mixing concept. The model considers an arbitrary mixing ratio between solute and solvent as well as the axial Taylor-Aris dispersion. A micromixer was designed and fabricated based on lamination of four polymer layers. The layers were machined using a CO2 laser. Time-interleaved segmentation was realized by two piezoelectric valves. The sheath streams for hydrodynamic focusing are introduced through the other two inlets. A special measurement set-up was designed with synchronization of the mixer's switching signal and the camera's trigger signal. The set-up allows a relatively slow and low-resolution CCD camera to freeze and to capture a large transient concentration field. The concentration profile along the mixing channel agrees qualitatively well with the analytical model. The analytical model and the device promise to be suitable tools for studying Taylor-Aris dispersion near the entrance of a flat microchannel.
Liquid Marble as Bioreactor for Engineering Three-Dimensional Toroid Tissues
Publisher: Springer Science and Business Media LLC
Date: 28-09-2017
DOI: 10.1038/S41598-017-12636-5
Abstract: Liquid marble is a liquid droplet coated with hydrophobic powder that can be used as a bioreactor. This paper reports the three-dimensional self-assembly and culture of a cell toroid in a slow-releasing, non-adhesive and evaporation-reducing bioreactor platform based on a liquid marble. The bioreactor is constructed by embedding a hydrogel sphere containing growth factor into a liquid marble filled with a suspension of dissociated cells. The hydrogel maintains the water content and concurrently acts as a slow-release carrier. The concentration gradient of growth factor induces cell migration and assembly into toroidal aggregates. An optimum cell concentration resulted in the toroidal (doughnut-like) tissue after 12 hours. The harvested cell toroids showed rapid closure of the inner opening when treated with the growth factor. We also present a geometric growth model to describe the shape of the toroidal tissue over time. In analogy to the classical two-dimensional scratch assay, we propose that the cell toroids reported here open up new possibilities to screen drugs affecting cell migration in three dimensions.
Electrochemical biosensing strategies for DNA methylation analysis
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.BIOS.2017.02.026
Abstract: DNA methylation is one of the key epigenetic modifications of DNA that results from the enzymatic addition of a methyl group at the fifth carbon of the cytosine base. It plays a crucial role in cellular development, genomic stability and gene expression. Aberrant DNA methylation is responsible for the pathogenesis of many diseases including cancers. Over the past several decades, many methodologies have been developed to detect DNA methylation. These methodologies range from classical molecular biology and optical approaches, such as bisulfite sequencing, microarrays, quantitative real-time PCR, colorimetry, Raman spectroscopy to the more recent electrochemical approaches. Among these, electrochemical approaches offer sensitive, simple, specific, rapid, and cost-effective analysis of DNA methylation. Additionally, electrochemical methods are highly amenable to miniaturization and possess the potential to be multiplexed. In recent years, several reviews have provided information on the detection strategies of DNA methylation. However, to date, there is no comprehensive evaluation of electrochemical DNA methylation detection strategies. Herein, we address the recent developments of electrochemical DNA methylation detection approaches. Furthermore, we highlight the major technical and biological challenges involved in these strategies and provide suggestions for the future direction of this important field.
Pressure-Driven Filling of Closed-End Microchannel: Realization of Comb-Shaped Transducers for Acoustofluidics
Publisher: American Physical Society (APS)
Date: 20-11-2018
Continuous flow polymerase chain reaction using a hybrid PMMA-PC microchip with improved heat tolerance
Publisher: Elsevier BV
Date: 28-03-2008
Unintentionally Doped Epitaxial 3C-SiC(111) Nanothin Film as Material for Highly Sensitive Thermal Sensors at High Temperatures
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2018
Statistical Detection of Short Periodic Gene Expression Time Series Profiles
Publisher: AIP
Date: 2007
DOI: 10.1063/1.2816619
An efficient microfluidic sorter: implementation of double meandering micro striplines for magnetic particles switching
Publisher: Springer Science and Business Media LLC
Date: 28-11-2010
Rapid, Simple and Inexpensive Fabrication of Paper-based Analytical Devices by Parafilm® Hot Pressing
Publisher: MDPI AG
Date: 03-12-2021
DOI: 10.20944/PREPRINTS202112.0046.V1
Abstract: Paper-based analytical devices have been substantially developed in recent decades. Many fabrication techniques for paper-based analytical devices have been demonstrated and reported. Herein we report a relatively rapid, simple, and inexpensive method for fabricating paper-based analytical devices using parafilm hot pressing. We studied and optimized the effect of the key fabrication parameters, namely pressure, temperature, and pressing time. We discerned the optimal conditions, including pressure of 3.8 MPa (3 tons), temperature of 80oC, and 3 minutes of pressing time, with the smallest hydrophobic barrier size (821 & micro m) being governed by laminate mask and parafilm dispersal from pressure and heat. Physical and biochemical properties were evaluated to substantiate the paper functionality for analytical devices. Wicking speed in the fabricated paper strips was slightly slower than that of non-processed paper, resulting from reducing paper pore size. A colorimetric immunological assay was performed to demonstrate the protein binding capacity of the paper-based device after exposure to pressure and heat from the fabrication. Moreover, mixing in two-dimensional paper-based device and flowing in a three-dimensional counterpart were thoroughly investigated, demonstrating that the paper device from this fabrication process is potentially applicable as analytical devices for biomolecule detection. Fast, easy, and inexpensive parafilm hot press fabrication presents an opportunity for researchers to develop paper-based analytical devices in resource-limited environments.
Experimental and Numerical Investigation of Droplet Transport in a Diffuser/Nozzle Structure
Publisher: ASMEDC
Date: 2009
Abstract: This paper investigates the droplet behavior in serially connected diffuser/nozzle structures using experimental and simulation methods. The serial structures act as diffusers in the expanding flow direction, and as nozzles in the converging flow direction. The opening angle of the structures is 45 degree. The test devices were fabricated in polydimethylsiloxane (PDMS) using soft lithography technique. The droplets under investigation were formed using T-junctions. Mineral oil with 2%w/w surfactant Span 80 and de-ionized (DI) water with fluorescent dye work as the carrier phase and the dispersed phase, respectively. The droplet behavior was captured using a CCD camera. The corresponding pressure drops across the test section were measured in both diffuser and nozzle flow direction using an external pressure sensor connected to the pressure port integrated on the device. The pressure drops across the test structure of two cases, with and without droplet, were analyzed and compared. The experimental results showed a linear relationship between the pressure drop and the oil flow rate. Furthermore, rectification effect was observed in the test device. The pressure drop in the diffuser configuration is higher than that of the nozzle configuration. Numerical models were employed to study the dynamics of the pressure drop across the diffuser/nozzle structures as well as the deformation of the droplet, which is modelled using level-set method. Corresponding to the experiments, two cases with and without were investigated and compared.
A novel circular ferro-fluid driven flow-through microchip for rapid DNA amplification
Publisher: IEEE
Date: 2007
Thermal Flow Sensors for Harsh Environments
Publisher: MDPI AG
Date: 08-09-2017
DOI: 10.3390/S17092061
Asymmetric heat transfer in liquid–liquid segmented flow in microchannels
Publisher: Elsevier BV
Date: 10-2014
Magnetofluidic micromixer based on a complex rotating magnetic field
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7RA08073E
Abstract: We report a magnetically actuated micromixer for mixing non-magnetic microparticles in a microfluidic system.
High-Throughput Polymerase Chain Reaction in Parallel Circular Loops Using Magnetic Actuation
Publisher: American Chemical Society (ACS)
Date: 24-06-2008
DOI: 10.1021/AC800787G
Abstract: We report here a novel multichannel closed-loop magnetically actuated microchip for high-throughput polymerase chain reaction (PCR). This is achieved by designing a series of concentric circular channels on one microchip and exploiting a magnetic force to drive DNA s les flowing continuously through the closed loops. The magnetic force arises from an external permanent magnet through ferrofluid plugs inside the microchannels. The magnet enables simultaneous actuation of DNA s les in all the channels. As the s les go around the loops, they pass through three preset temperature zones. Parameters of PCR, such as incubation time, temperatures, and number of cycles, can be fully controlled and adjusted. High reproducibility was achieved for different channels in the same run and for the same channels in consecutive runs. Genetically modified organisms (GMOs) were lified simultaneously using the developed device. This simple, reliable, and high-throughput PCR microchip would find wide applications in forensic, clinical, and biological fields.
Sheathless separation of microalgae from bacteria using a simple straight channel based on viscoelastic microfluidics.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9LC00482C
Abstract: Microalgae cells have been recognized as a promising sustainable resource to meet worldwide growing demands for renewable energy, food, livestock feed, water, cosmetics, pharmaceuticals, and materials. In order to ensure high-efficiency and high-quality production of biomass, biofuel, or bio-based products, purification procedures prior to the storage and cultivation of the microalgae from contaminated bacteria are of great importance. The present work proposed and developed a simple, sheathless, and efficient method to separate microalgae Chlorella from bacteria Bacillus Subtilis in a straight channel using the viscoelasticity of the medium. Microalgae and bacteria migrate to different lateral positions closer to the channel centre and channel walls respectively. Fluorescent microparticles with 1 μm and 5 μm diameters were first used to mimic the behaviours of bacteria and microalgae to optimize the separating conditions. Subsequently, size-based separation in Newtonian fluid and in viscoelastic fluid in straight channels with different aspect ratios was compared and demonstrated. Under the optimal condition, the removal ratio for 1 μm microparticles and separation efficiency for 5 μm particles can reach up to 98.28% and 93.85% respectively. For bacteria and microalgae cells separation, the removal ratio for bacteria and separation efficiency for microalgae cells is 92.69% and 100% respectively. This work demonstrated the continuous and sheathless separation of microalgae from bacteria for the first time by viscoelastic microfluidics. This technique can also be applied as an efficient and user-friendly method to separate mammalian cells or other kinds of cells.
Microfluidic sensor for dynamic surface tension measurement
Publisher: Institution of Engineering and Technology (IET)
Date: 2006
Abstract: A novel microfluidic sensor for measuring dynamic gas-liquid interfacial tension is reported. The device consists of a microfluidic chip with a microchannel network and an optical detection system. The s le is introduced into a main channel, while air is injected through a T-junction. Owing to the fixed flow rate ratio used for the sensor, surface tension is the only parameter determining bubble formation frequency, which can be measured by optical detection. Although the bubble is represented by a pulse in the output signal, the formation frequency is simply the frequency of the output signal. Measurements were carried out for aqueous solutions with different concentrations of the ionic surfactant cetyl trimethyl ammonium bromide. Surface tensions of these solutions were calibrated with a commercial tensiometer. The measurement results show a clear relationship between surface tension and formation frequency. The sensor can be used to identify the critical micelle concentration of the surfactant. The sensor potentially allows the use of a minute amount of s le compared with the relatively large amount required for existing commercial systems.
Biclusters Visualization and Detection Using Parallel Coordinate Plots
Publisher: AIP
Date: 2007
DOI: 10.1063/1.2816614
Real-time control of inertial focusing in microfluidics using dielectrophoresis (DEP)
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4RA13075H
Abstract: In this work, we explored the possibility of combining dielectrophoresis (DEP) and inertial focusing in a fully coupled manner and proposed a new concept, which is called DEP-inertial microfluidics. A vertical DEP force is used to tune the inertial focusing pattern and position in three dimensions.
Uniaxial Cyclic Cell Stretching Device for Accelerating Cellular Studies
Publisher: MDPI AG
Date: 05-07-2023
DOI: 10.20944/PREPRINTS202307.0263.V1
Abstract: Cellular response to mechanical stimuli is a crucial factor for maintaining cell homeostasis. The interaction between extracellular matrix and mechanical stress plays a significant role in organ-izing the cytoskeleton and aligning cells. Tools that apply mechanical forces to cells and tissues, as well as those capable of measuring the mechanical properties of biological cells, have greatly contributed to our understanding of fundamental mechanobiology. These tools have been exten-sively employed to unveil the substantial influence of mechanical cues on the development and progression of various diseases. In this report, we present an economical and high-performance uniaxial cell stretching device. This paper reports the detailed operation concept of the device, ex-perimental design, and characterization. The device was tested with MDA-MB-231 breast cancer cells. Experimental results agree well with previously documented morphological changes re-sulting from stretching forces on cancer cells. Remarkably, our new device demonstrates compa-rable cellular changes within a 30-minute compared to the previous 2-hour stretching duration. Moreover, the device design incorporates an open-source software interface, facilitating conven-ient parameter adjustments such as strain, stretching speed, frequency, and duration. Its versatil-ity enables seamless integration with various optical microscopes, thereby yielding novel insights into the realm of mechanobiology.
Enhanced electrophoretic DNA separation in photonic crystal fiber
Publisher: Springer Science and Business Media LLC
Date: 27-05-2009
DOI: 10.1007/S00216-009-2833-6
Abstract: Joule heating generated by the electrical current in capillary electrophoresis leads to a temperature gradient along the separation channel and consequently affects the separation quality. We describe a method of reducing the Joule heating effect by incorporating photonic crystal fiber into a micro capillary electrophoresis chip. The photonic crystal fiber consists of a bundle of extremely narrow hollow channels, which ideally work as separation columns. Electrophoretic separation of DNA fragments was simultaneously but independently carried out in 54 narrow capillaries with a diameter of 3.7 microm each. The capillary bundle offers more efficient heat dissipation owing to the high surface-to-volume ratio. Under the same electrical field strength, notable improvement in resolution was obtained in the capillary bundle chip.
Experimental and numerical investigation of thermal chaotic mixing in a T-shaped microchannel
Publisher: Springer Science and Business Media LLC
Date: 17-04-2011
MEMS-micropumps: A review
Publisher: ASME International
Date: 28-05-2002
DOI: 10.1115/1.1459075
Abstract: Microfluidics has emerged from the MEMS-technology as an important research field and a promising market. This paper gives an overview on one of the most important microfluidic components: the micropump. In the last decade, various micropumps have been developed. There are only a few review papers on microfluidic devices and none of them were dedicated only to micropumps. This review paper outlines systematically the pump principles and their realization with MEMS-technology. Comparisons regarding pump size, flow rate, and backpressure will help readers to decide their proper design before starting a microfluidics project. Different pump principles are compared graphically and discussed in terms of their advantages and disadvantages for particular applications.
A membraneless hydrogen peroxide fuel cell using Prussian Blue as cathode material
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2EE21806B
Laser induced graphene for biosensors
Publisher: Elsevier BV
Date: 09-2020
Electrostatically excited liquid marble as a micromixer
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1RE00121C
Abstract: Liquid marble as a micromixer. Particles suspended in a transparent liquid marble is dispersed in a time lapse photo. The colour change from red to purple shows the particle position from the first frame to the last frame.
Hydrophobically Modified Gelatin Particles for Production of Liquid Marbles
Publisher: MDPI AG
Date: 10-11-2022
Abstract: The unique properties and morphology of liquid marbles (LMs) make them potentially useful for various applications. Non-edible hydrophobic organic polymer particles are widely used to prepare LMs. It is necessary to increase the variety of LM particles to extend their use into food and pharmaceuticals. Herein, we focus on hydrophobically modified gelatin (HMG) as a base material for the particles. The surface tension of HMG decreased as the length of alkyl chains incorporated into the gelatin and the degree of substitution (DS) of the alkyl chains increased. HMG with a surface tension of less than 37.5 mN/m (determined using equations based on the Young–Dupré equation and Kaelble–Uy theory) successfully formed LMs of water. The minimum surface tension of a liquid in which it was possible to form LMs using HMG particles was approximately 53 mN/m. We also showed that the liquid-over-solid spreading coefficient SL/S is a potential new factor for predicting if particles can form LMs. The HMG particles and the new system for predicting LM formation could expand the use of LMs in food and pharmaceuticals.
Analytical Modeling of Slip Flow in Parallel-plate Microchannels
Publisher: Bentham Science Publishers Ltd.
Date: 11-2013
Micromachined polymer electrolyte membrane and direct methanol fuel cells - A review
Publisher: IOP Publishing
Date: 06-03-2006
Thermoresistive Effect for Advanced Thermal Sensors: Fundamentals, Design Considerations, and Applications
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2017
Lithography and Etching‐Free Microfabrication of Silicon Carbide on Insulator Using Direct UV Laser Ablation
Publisher: Wiley
Date: 06-02-2020
Onset of thermomagnetic convection around a vertically oriented hot-wire in ferrofluid
Publisher: Elsevier BV
Date: 06-2018
Thermocapillary actuation of droplet in a planar microchannel
Publisher: Springer Science and Business Media LLC
Date: 06-11-2008
Disposable flow cytometer with high efficiency in particle counting and sizing using an optofluidic lens
Publisher: The Optical Society
Date: 18-02-2011
DOI: 10.1364/OL.36.000657
Programmable two-dimensional actuation of ferrofluid droplet using planar microcoils
Publisher: IOP Publishing
Date: 02-12-2010
Automatic Live and Dead Cell Classification via Hyperspectral Imaging
Publisher: IEEE
Date: 09-2019
A stretchable micromixer with enhanced performance for intermediate Reynolds numbers
Publisher: Research Square Platform LLC
Date: 03-09-2021
DOI: 10.21203/RS.3.RS-870684/V2
Abstract: Chemical reactions in microscale require good mixing at a relatively low flowrate. However, mixing in microscale faces the major challenge of stable laminar flow associated with the low Reynolds number, the relative ratio between inertial force and viscous force. For low Reynolds numbers of less than unity, mixing occurs due to molecular diffusion. For high Reynolds number of more than several tens, chaotic advection enhances mixing. However, in the intermediate regime, mixing is not efficient. This paper reports a stretchable micromixer with dynamically tuneable channel dimensions. Periodically stretching the device changes the channel geometry and the curvature induced secondary Dean flows. The dynamically evolving secondary and main flows in the mixing channel result in chaotic advection and enhance mixing. The concept was demonstrated in a stretchable micromixer with a serpentine channel. We evaluated the performance of this stretchable micromixer both experimentally and numerically. At the intermediate range of Reynolds numbers from 4 to 17, the periodically stretched micromixer showed a better mixing efficiency than the non-stretched counterpart. Therefore, our stretchable micromixer is a potential candidate for applications where precious reagents need to be mixed at relatively low flow rate conditions.
Acoustofluidic control of bubble size in microfluidic flow-focusing configuration
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4LC01139B
Abstract: We report a new technology using acoustofluidic to achieve controllable manipulation of the size of the bubbles formed.
A stretchable micrometer with enhanced performance for intermediate Reynolds numbers
Publisher: Research Square Platform LLC
Date: 02-09-2021
DOI: 10.21203/RS.3.RS-870684/V1
Abstract: Chemical reactions in microscale require good mixing at a relatively low flowrate. However, mixing in microscale faces the major challenge of stable laminar flow associated with the low Reynolds number, the relative ratio between inertial force and viscous force. For low Reynolds numbers of less than unity, mixing occurs due to molecular diffusion. For high Reynolds number of more than several tens, chaotic advection enhances mixing. However, in the intermediate regime, mixing is not efficient. This paper reports a stretchable micromixer with dynamically tuneable channel dimensions. Periodically stretching the device changes the channel geometry and the curvature induced secondary Dean flows. The dynamically evolving secondary and main flows in the mixing channel result in chaotic advection and enhance mixing. The concept was demonstrated in a stretchable micromixer with a serpentine channel. We evaluated the performance of this stretchable micromixer both experimentally and numerically. At the intermediate range of Reynolds numbers from 4 to 17, the periodically stretched micromixer showed a better mixing efficiency than the non-stretched counterpart. Therefore, our stretchable micromixer is a potential candidate for applications where precious reagents need to be mixed at relatively low flow rate conditions.
A promoter-level mammalian expression atlas
Publisher: Springer Science and Business Media LLC
Date: 03-2014
DOI: 10.1038/NATURE13182
An analytical model for a liquid plug moving in curved microchannels
Publisher: Elsevier BV
Date: 04-2010
Self-Aligned Interdigitated Transducers for Acoustofluidics
Publisher: MDPI AG
Date: 22-11-2016
DOI: 10.20944/PREPRINTS201611.0086.V2
Abstract: Surface acoustic wave (SAW) is effective for the manipulation of fluids and particles in microscale. The current approach of integrating interdigitated transducers (IDTs) for SAW generation into microfluidic channels involves complex and laborious microfabrication steps. These steps often require the full access to clean room facilities and hours to align the transducers to the precise location. This work presents an affordable and innovative method for fabricating SAW-based microfluidic devices without the need of clean room facilities and alignment. The IDTs and microfluidic channels are fabricated in the same process and thus precisely self-aligned in accordance with the device design. With the use of the developed fabrication approach, a few types of different SAW-based microfluidic devices have been fabricated and demonstrated for particle separation and active droplet generation.
Self-Aligned Interdigitated Transducers for Acoustofluidics
Publisher: MDPI AG
Date: 17-11-2016
DOI: 10.20944/PREPRINTS201611.0086.V1
Abstract: Surface acoustic wave (SAW) is effective for the manipulation of fluids and particles in microscale. The current approach of integrating interdigitated transducers (IDTs) for SAW generation into microfluidic channels involves complex and laborious microfabrication steps. These steps often require the full access to clean room facilities and hours to align the transducers to the precise location. This work presents an affordable and innovative method for fabricating SAW-based microfluidic devices without the need of clean room facilities and alignment. The IDTs and microfluidic channels are fabricated in the same process and thus precisely self-aligned in accordance with the device design. With the use of the developed fabrication approach, a few types of different SAW-based microfluidic devices have been fabricated and demonstrated for particle separation and active droplet generation.
A novel wind sensor concept based on thermal image measurement using a temperature sensor array
Publisher: Elsevier BV
Date: 02-2004
The application of μPIV technique in the study of magnetic flows in a micro-channel
Publisher: Elsevier BV
Date: 03-2005
Numerical study of the formation process of ferrofluid droplets
Publisher: AIP Publishing
Date: 07-2011
DOI: 10.1063/1.3614569
Abstract: This paper numerically investigates the influence of a uniform magnetic field on the droplet formation process at a microfluidic flow focusing configuration. The mathematical model was formulated by considering the balance of forces such as interfacial tension, magnetic force, and viscous stress across the liquid/liquid interface. A linearly magnetizable fluid was assumed. The magnetic force acts as a body force where the magnetic permeability jumps across the interface. The governing equations were solved with finite volume method on a Cartesian fixed staggered grid. The evolution of the interface was captured by the particle level set method. The code was validated with the equilibrium steady state of a ferrofluid droplet exposed to a uniform magnetic field. The evolution of the droplet formation in a flow focusing configuration was discussed. The paper mainly analyzes the effects of magnetic Bond number and the susceptibility on the velocity field and the droplet size. The droplet size increased with increasing magnetic strength and susceptibility.
Magnetofluidics for manipulation of convective heat transfer
Publisher: Elsevier BV
Date: 02-2017
Circulating tumor microemboli: Progress in molecular understanding and enrichment technologies
Publisher: Elsevier BV
Date: 07-2018
DOI: 10.1016/J.BIOTECHADV.2018.05.002
Abstract: Circulating tumor cells (CTCs) and their clusters, also known as circulating tumor microemboli (CTM), have emerged as valuable tool that can provide mechanistic insights into the tumor heterogeneity, clonal evolution, and stochastic events within the metastatic cascade. However, recent investigations have hinted that CTM may not be mere aggregates of tumor cells but cells comprising CTM exhibit distinct phenotypic and molecular characteristics in comparison to single CTCs. Moreover, in many cases CTM demonstrated higher metastatic potential and resistance to apoptosis as compared to their single cell counterparts. Thus, their evaluation and enumeration may provide a new dimension to our understanding of cancer biology and metastatic cancer spread as well as offer novel theranostic biomarkers. Most of the existing technologies for isolation of hematogenous tumor cells largely favor single CTCs, hence there is a need to devise new approaches, or re-configure the existing ones, for specific and efficient CTM isolation. Here we review existing knowledge and insights on CTM biology. Furthermore, a critical commentary on current and emerging trends in CTM enrichment and characterization along with recently developed ex-vivo CTC expansion methodologies is presented with the aim to facilitate researchers to identify further avenues of research and development.
Scattering and attenuation of surface acoustic waves in droplet actuation
Publisher: IOP Publishing
Date: 29-07-2008
An electrochemical method for sensitive and rapid detection of FAM134B protein in colon cancer samples
Publisher: Springer Science and Business Media LLC
Date: 09-03-2017
DOI: 10.1038/S41598-017-00206-8
Abstract: Despite the excellent diagnostic applications of the current conventional immunoassay methods such as ELISA, immunostaining and Western blot for FAM134B detection, they are laborious, expensive and required a long turnaround time. Here, we report an electrochemical approach for rapid, sensitive, and specific detection of FAM134B protein in biological (colon cancer cell extracts) and clinical (serum) s les. The approach utilises a differential pulse voltammetry (DPV) in the presence of the [Fe(CN) 6 ] 3−/4− redox system to quantify the FAM134B protein in a two-step strategy that involves ( i ) initial attachment of FAM134B antibody on the surface of extravidin-modified screen-printed carbon electrode, and ( ii ) subsequent detection of FAM134B protein present in the biological/clinical s les. The assay system was able to detect FAM134B protein at a concentration down to 10 pg μL −1 in phosphate buffered saline (pH 7.4) with a good inter-assay reproducibility (% RSD = .64, n = 3). We found excellent sensitivity and specificity for the analysis of FAM134B protein in a panel of colon cancer cell lines and serum s les. Finally, the assay was further validated with ELISA method. We believe that our assay could potentially lead a low-cost alternative to conventional immunological assays for target antigens analysis in point-of-care applications.
Diagnosis of transient electrokinetic flow in microfluidic channels
Publisher: AIP Publishing
Date: 2007
DOI: 10.1063/1.2430502
Abstract: Measuring the electro-osmotic velocity distributions in microchannels is usually performed for steady-state electrokinetic flows. Characterizing time-dependent electrokinetic flows is of importance to the development of microfluidic devices such as rapid capillary electrophoretic separation system, ac pumps, novel micromixers, etc. In this paper, we use a micron-resolution particle image velocimetry (micro-PIV) based phase locking technique with an ordinary PIV charge coupled device (CCD) camera to carry out an experimental study of the transient electrokinetic flow in microchannels by synchronizing different trigger signals for the laser, CCD camera, and in-house designed high-voltage switch. With the transient micro-PIV technique, we further propose a method to decouple the particle electrophoretic velocity from the micro-PIV measured velocity and to determine the zeta potential of the channel wall. The time evolution of the full-field, electro-osmotic velocity distributions in both open- and closed-end rectangular microchannels is obtained. Using the slip velocity approach and the measured channel zeta potential, the theoretical predictions of the transient electro-osmotic flow in the open- and closed-end microchannels are obtained, and they are found to be in good agreement with the experimental results.
Symmetry Plane Detection in Brain Image Analysis: A Survey
Publisher: Bentham Science Publishers Ltd.
Date: 11-2013
Microfluidic Technology for the Generation of Cell Spheroids and Their Applications
Publisher: MDPI AG
Date: 23-03-2017
DOI: 10.3390/MI8040094
Thermally controlled droplet formation in flow focusing geometry: formation regimes and effect of nanoparticle suspension
Publisher: IOP Publishing
Date: 21-07-2008
Behavior of microdroplets in diffuser/nozzle structures
Publisher: Springer Science and Business Media LLC
Date: 07-11-2008
In-air particle generation by on-chip electrohydrodynamics
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0LC01247E
Abstract: This work demonstrates the capability of simultaneously generating-and-delivering a stream of micro/nanoparticles range of 0.75–2 μm by electrohydrodynamics, without any restrictions of either the collector or the assistance of external flow.
Electrohydrodynamic and shear-stress interfacial instability of two streaming viscous liquid inside a microchannel for normal electric fields
Publisher: ASMEDC
Date: 2011
Abstract: The electrohydrodynamic and shear-stress instability of the interface between two viscous fluids with different electrical properties under constant flowrates in microchannel is analytically and experimentally investigated. In analytical model, the two-layer system is subjected to an electric field normal to the interface between the two fluids the electric field, surface charge and fluid dynamic are coupled only at the interface. In the experiments, two immiscible fluids, aqueous NaHCO3 (high electrical mobility fluid) and Poly (dimethylsiloxane) (low electrical mobility fluid) are pushed into the PMMA microchannel using syringes and syringe pump. The normal electric field is added to the aqueous NaHCO3 using high voltage power supply the perturbation electric field are added using a function generator and a power lifier. The results showed that the electric fields can induce the instability of fluids in microchannel the increasing of viscosity and flowrates has a stabilizing effect to the flow but increasing of thickness has a destabilizing effect to the flow. The results also show that the analytical solution has a good agreement with the experimental results.
Tunable optofluidic aperture configured by a liquid-core/liquid-cladding structure
Publisher: The Optical Society
Date: 05-05-2011
DOI: 10.1364/OL.36.001767
Highly sensitive 4H-SiC pressure sensor at cryogenic and elevated temperatures
Publisher: Elsevier BV
Date: 10-2018
Slug flow heat transfer without phase change in microchannels: A review
Publisher: Elsevier BV
Date: 04-2015
Multiplexed serpentine microchannels for high-throughput sorting of disseminated tumor cells from malignant pleural effusion
Publisher: Elsevier BV
Date: 06-2021
Tunable particle separation in a hybrid dielectrophoresis (DEP)- inertial microfluidic device
Publisher: Elsevier BV
Date: 08-2018
Numerical simulation of combined natural and thermomagnetic convection around a current carrying wire in ferrofluid
Publisher: Elsevier BV
Date: 11-2019
A portable, hand-powered microfluidic device for sorting of biological particles
Publisher: Springer Science and Business Media LLC
Date: 12-12-2018
Detection of the SARS-CoV-2 humanized antibody with paper-based ELISA
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0AN01609H
Abstract: This work reports the development of a rapid, simple and inexpensive colorimetric paper-based assay for the detection of the severe acute respiratory symptom coronavirus 2 (SARS-CoV-2) humanized antibody.
Fabrication and Experimental Characterization of Nanochannels
Publisher: ASMEDC
Date: 2009
Abstract: Nanofluidics is the science and technology involving a fluid flowing in or around structures with a least one dimension in the nanoscale, which is defined as the range from 1 nm to 100 nm. In this paper, we present the fabrication and characterization of nanochannels in silicon and glass. Since the lateral dimension of the channels is limited by the wavelength of UV light used in photolithography, the channel width can only be fabricated in the micrometer scale. However, the depth of the channel can be controlled precisely by etch rate of reactive ion etching (RIE). Microchannels and access holes were etched with deep reactive ion etching (DRIE). Both nanonochannel and microchannel were sealed by a Pyrex glass wafer using anodic bonding. The fabricated nanochannels were characterized by capillary filling and evaporation experiments. Due to the small channel height and weak fluorescent signal, fluorescent techniques are not suitable for the characterization of the nanochannels. A long exposure time due to the limited amount of fluorescent molecules inhibit the measurement of transient and dynamic processes. However, as the channel height shorter than all visible wavelengths, the contrast in refractive indices of air and liquid allow clear visualization of nanochannels filled with liquids. Automatic image processing with MATLAB allows the evaluation of capillary filling in nanochannels. Interesting phenomena and discrepancies with conventional theories are presented.
Critical Trapping Conditions for Floating Liquid Marbles
Publisher: American Physical Society (APS)
Date: 02-01-2020
Nonlinear diffusive mixing in microchannels: theory and experiments
Publisher: IOP Publishing
Date: 06-02-2004
Effect of Core Liquid Surface Tension on the Liquid Marble Shell
Publisher: Wiley
Date: 23-11-2020
A polymeric piezoelectric micropump based on lamination technology
Publisher: IOP Publishing
Date: 06-02-2004
Electroosmotic control of width and position of liquid streams in hydrodynamic focusing
Publisher: Springer Science and Business Media LLC
Date: 28-01-2009
Biophysical properties of cells for cancer diagnosis
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.JBIOMECH.2019.02.006
Abstract: Biophysical properties associated with the microenvironment of a tumor has been recognized as an important modulator for cell behaviour and function. Particularly, tissue rigidity is important during tumor carcinogenesis as it affects the tumor's ability to metastasis. Multiple downstream pathways are affected with a difference in rigidity of the extracellular matrix. The insight into tumor mechanosignalling represents a promising field that may lead to novel approaches for cancer diagnostics. Measurement of rigidity of the extracellular matrix or the tissue is a potential diagnostics approach for cancer detection. Altered extracellular matrix states persist for a long period of time and have lower heterogeneity compared to protein or genetic markers, therefore are more reliable as biomarkers. On the other hand, measurement of different kinase associated proteins or transcripts provide an early insight into potential transition of cells towards metastasis. Co-localization of transcriptional factors like YAP/TAZ provide an insight to determine if the cells are undergoing metastatic changes. This review explains the unique biophysical properties of the tumor microenvironment that present the potential targets for the diagnosis of cancer.
Manipulation of ferrofluid droplets using planar coils
Publisher: AIP Publishing
Date: 31-07-2006
DOI: 10.1063/1.2335403
Abstract: In this letter, the authors report a system for magnetic manipulation of ferrofluid droplets and their dynamic behavior. The magnetic field was generated by an array of planar coils, which were fabricated on a double-sided printed circuit board (PCB). The permanent magnetic moment of the ferrofluid droplet was created by the field of a pair of permanent magnets. The motion of the ferrofluid droplet is further aligned in a virtual channel formed by a pair of planar coils. Two other planar coils on the other side of the PCB drive the droplet along this virtual channel. The direction of the droplet motion can be controlled by reversing the electric current in the coils. Based on the experimental results, a larger droplet size, a lower viscosity of the surrounding medium, and a higher electric current will increase the droplet velocity.
Biocomposites of Natural Fibers and Poly(3‐Hydroxybutyrate) and Copolymers: Improved Mechanical Properties Through Compatibilization at the Interface
Publisher: Wiley
Date: 08-10-2008
A rapid magnetofluidic micromixer using diluted ferrofluid
Publisher: MDPI AG
Date: 25-01-2017
DOI: 10.3390/MI8020037
Polymeric Labs on a Chip for Sustainable Development
Publisher: ASMEDC
Date: 2009
Abstract: Sustainable development is a process involving the society, the environment and the economy to meet human needs while preserving the environment. Sustainable development not only addresses the present needs but also the future needs of humanity. Lab on a chip technologies play an important role in this process. This paper reports ex les of low-cost polymeric lab-on-a-chip (LOC) devices for sustainable development in food supply, namely the detection of genetically modified organisms (GMOs) and the detection of insecticides in agriculture. As the first ex le, the paper presents a close-loop ferrofluid-driven LOC for rapid lification and detection of GMOs. Polymerase chain reaction (PCR) s le was contained in a circular closed microchannel and driven by magnetic force generated by an external magnet through a small oil-based ferrofluid plug. Successful lification of genetically modified soya and maize were achieved in less than 13 minutes. The LOC provides a cost saving and less time-consuming way to conduct preliminary screening of GMOs. As the second ex le, the paper reports a LOC for detection of organophosphorus insecticides for occupational hygiene in agriculture. Nerve agent sarin diluted in water was used to test the device concept. The s le was tested for trace levels of regenerated sarin using immobilised cholinesterase on the chip. Activity of immobilised cholinesterase was monitored by enzyme-assisted reaction of a substrate and reaction of the end-product with a chromophore. Resultant changes in chromophore-induced absorbance were recorded on the. Loss of enzyme activity obtained prior and after passage of the treated blood s le, as shown by a decrease in recorded absorbance values, indicates the presence of either free or regenerated nerve agent in the s le.
Polymeric nanomaterial strategies to encapsulate and deliver biological drugs: points to consider between methods
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2BM01594C
Abstract: Different techniques developed for the encapsulation of biological drugs within polymeric nanoparticles.
Dean-flow-coupled elasto-inertial three-dimensional particle focusing under viscoelastic flow in a straight channel with asymmetrical expansion–contraction cavity arrays
Publisher: AIP Publishing
Date: 07-2015
DOI: 10.1063/1.4927494
Abstract: In this paper, 3D particle focusing in a straight channel with asymmetrical expansion–contraction cavity arrays (ECCA channel) is achieved by exploiting the dean-flow-coupled elasto-inertial effects. First, the mechanism of particle focusing in both Newtonian and non-Newtonian fluids was introduced. Then particle focusing was demonstrated experimentally in this channel with Newtonian and non-Newtonian fluids using three different sized particles (3.2 μm, 4.8 μm, and 13 μm), respectively. Also, the effects of dean flow (or secondary flow) induced by expansion–contraction cavity arrays were highlighted by comparing the particle distributions in a single straight rectangular channel with that in the ECCA channel. Finally, the influences of flow rates and distances from the inlet on focusing performance in the ECCA channel were studied. The results show that in the ECCA channel particles are focused on the cavity side in Newtonian fluid due to the synthesis effects of inertial and dean-drag force, whereas the particles are focused on the opposite cavity side in non-Newtonian fluid due to the addition of viscoelastic force. Compared with the focusing performance in Newtonian fluid, the particles are more easily and better focused in non-Newtonian fluid. Besides, the Dean flow in visco-elastic fluid in the ECCA channel improves the particle focusing performance compared with that in a straight channel. A further advantage is three-dimensional (3D) particle focusing that in non-Newtonian fluid is realized according to the lateral side view of the channel while only two-dimensional (2D) particle focusing can be achieved in Newtonian fluid. Conclusively, this novel Dean-flow-coupled elasto-inertial microfluidic device could offer a continuous, sheathless, and high throughput (& 000 s−1) 3D focusing performance, which may be valuable in various applications from high speed flow cytometry to cell counting, sorting, and analysis.
Microfluidic gut-on-a-chip with three-dimensional villi structure
Publisher: Springer Science and Business Media LLC
Date: 27-04-2017
DOI: 10.1007/S10544-017-0179-Y
Abstract: Current in vitro gut models lack physiological relevance, and various approaches have been taken to improve current cell culture models. For ex le, mimicking the three-dimensional (3D) tissue structure or fluidic environment has been shown to improve the physiological function of gut cells. Here, we incorporated a collagen scaffold that mimics the human intestinal villi into a microfluidic device, thus providing cells with both 3D tissue structure and fluidic shear. We hypothesized that the combined effect of 3D structure and fluidic shear may provide cells with adequate stimulus to induce further differentiation and improve physiological relevance. The physiological function of our '3D gut chip' was assessed by measuring the absorptive permeability of the gut epithelium and activity of representative enzymes, as well as morphological evaluation. Our results suggest that the combination of fluidic stimulus and 3D structure induces further improvement in gut functions. Our work provides insight into the effect of different tissue environment on gut cells.
Capillarity: revisiting the fundamentals of liquid marbles
Publisher: Springer Science and Business Media LLC
Date: 23-09-2020
Numerical Studies of Sessile Droplet Shape with Moving Contact Lines
Publisher: Bentham Science Publishers Ltd.
Date: 03-2011
Advances in Microfluidics‐Based Assisted Reproductive Technology: From Sperm Sorter to Reproductive System‐on‐a‐Chip
Publisher: Wiley
Date: 15-01-2018
An analytical model for plug flow in microcapillaries with circular cross section
Publisher: Elsevier BV
Date: 10-2011
Direct Measurement of the Contents, Thickness, and Internal Pressure of Molybdenum Disulfide Nanoblisters
Publisher: American Chemical Society (ACS)
Date: 09-04-2020
Effects of hydrophobicity of the cathode catalyst layer on the performance of a PEM fuel cell
Publisher: Elsevier BV
Date: 03-2010
Flow visualization and heat transfer characteristics of gas–liquid two-phase flow in microtube under constant heat flux at wall
Publisher: Elsevier BV
Date: 2013
Thermal Flow Sensors for Harsh Environments
Publisher: MDPI AG
Date: 14-07-2017
DOI: 10.20944/PREPRINTS201707.0031.V1
Abstract: Flow sensing in hostile environment is of increasing interest for applications in automotive, aerospace, and chemical and resource industries. Compared to their counterparts, thermal flow sensors are attractive candidates due to the ease of fabrication, lack of moving parts and higher sensitivity. Recently, a number of thermal flow sensor prototypes have been reported in the literature demonstrating the measurement of fluid flows under hostile conditions. This paper summarizes the concept of thermal flow sensing, operational modes and transduction mechanisms. Then, the choice of materials and their corresponding properties are presented in details. The paper also reports recent progress in the development of thermal flow sensors for harsh environment. In addition, the issues and considerations in packaging are reviewed. Finally, we conclude the review with the future prospects.
Manipulation schemes and applications of liquid marbles for micro total analysis systems
Publisher: Elsevier BV
Date: 10-2018
Microfluidic chip with optical sensor for rapid detection of nerve agent Sarin in water samples
Publisher: SPIE
Date: 27-12-2006
DOI: 10.1117/12.697234
Stretching cells – An approach for early cancer diagnosis
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.YEXCR.2019.01.029
Abstract: Cells express multiple biophysical cues during migration, differentiation, and transformation. Probing and quantifying these biophysical cues could serve as a diagnostic tool for differentiating healthy with neoplastic cells. These biophysical cues may be utilized for diagnostic screening in cancer, as the tumor cells interact with the surrounding extracellular matrix (ECM). Stress and strain induced by the cancer cells and applied to the cancer cells have effects in cancer progression due to its influence in cell migration. It was reported that the introduction of compressive forces on cancerous cells triggers them to undergo apoptosis. In this report, we evaluated the effects of stretching forces on cancer cells by morphological analyses. We observed that cancer cells decrease their roundness (as determined by perimeter: area) increase their length and form filopodia in the initial stretching cycle. However, due to the increasing rigidity of the cells, they undergo apoptosis in later stretching cycles. These morphological changes were unique to breast cancer (MDA-MB-231) cells compared to the non-cancerous control. Elucidating and quantifying these morphological changes is potentially an early cancer diagnostic tool that may predict the propensity of the cancerous cells undergoing a metastatic transformation.
Investigation of active interface control of pressure driven two-fluid flow in microchannels
Publisher: Elsevier BV
Date: 02-2007
Micro check valves for integration into polymeric microfluidic devices
Publisher: IOP Publishing
Date: 19-08-2004
Microneedle Arrays for Sampling and Sensing Dermal Interstitial Fluid
Publisher: MDPI AG
Date: 30-03-2021
DOI: 10.20944/PREPRINTS202103.0720.V1
Abstract: Dermal interstitial fluid (ISF) is a novel source of biomarkers that can be considered as an alternative to blood s ling for disease diagnosis and treatment. Nevertheless, in vivo extraction and analysis of ISF are challenging. On the other hand, microneedle (MN) technology can address most of the challenges associated with dermal ISF extraction and is well-suited for long-term, continuous ISF monitoring as well as in situ detection. In this review, we first briefly summarise the different dermal ISF collection methods and compare them with MN methods. Next, we elaborate on the design considerations and biocompatibility of MNs. Subsequently, the fabrication technologies of various MNs used for dermal ISF extraction, including solid MNs, hollow MNs, porous MNs and hydrogel MNs, are thoroughly explained. In addition, different sensing mechanisms of ISF detection will be discussed in detail. Subsequently, we identify the challenges and propose the possible solutions associated with ISF extraction. A detailed investigation is provided for the transport and s ling mechanism of ISF in vivo. Also, the current in vitro skin model integrated with the MN arrays will be discussed. Finally, future directions to develop a point-of-care (POC) device to s le ISF are proposed.
Micromixers: Fundamentals, Design and Fabrication
Publisher: Elsevier
Date: 2008
A tuneable micro-optofluidic biconvex lens with mathematically predictable focal length
Publisher: Springer Science and Business Media LLC
Date: 04-2010
Multidisciplinary approach to maximize angiogenesis and wound healing using piezoelectric surgery, concentrated growth factors and photobiomodulation for dental implant placement surgery involving lateral wall sinus lift: Two case reports
Publisher: Publiverse Online S.R.L
Date: 28-04-2020
Highly sensitive pressure sensors employing 3C-SiC nanowires fabricated on a free standing structure
Publisher: Elsevier BV
Date: 10-2018
Predicting Outcomes in Men With Metastatic Nonseminomatous Germ Cell Tumors (NSGCT): Results From the IGCCCG Update Consortium
Publisher: American Society of Clinical Oncology (ASCO)
Date: 10-05-2021
DOI: 10.1200/JCO.20.03296
Abstract: The classification of the International Germ Cell Cancer Collaborative Group (IGCCCG) plays a pivotal role in the management of metastatic germ cell tumors but relies on data of patients treated between 1975 and 1990. Data on 9,728 men with metastatic nonseminomatous germ cell tumors treated with cisplatin- and etoposide-based first-line chemotherapy between 1990 and 2013 were collected from 30 institutions or collaborative groups in Europe, North America, and Australia. Clinical trial and registry data were included. Primary end points were progression-free survival (PFS) and overall survival (OS). The survival estimates were updated for the current era. Additionally, a novel prognostic model for PFS was developed in 3,542 patients with complete information on potentially relevant variables. The results were validated in an independent data set. Compared with the original IGCCCG publication, 5-year PFS remained similar in patients with good prognosis with 89% (87%-91%) versus 90% (95% CI, 89 to 91), but the 5-year OS increased from 92% (90%-94%) to 96% (95%-96%). In patients with intermediate prognosis, PFS remained similar with 75% (71%-79%) versus 78% (76%-80%) and the OS increased from 80% (76%-84%) to 89% (88%-91%). In patients with poor prognosis, the PFS increased from 41% (95% CI, 35 to 47) to 54% (95% CI, 52 to 56) and the OS from 48% (95% CI, 42 to 54) to 67% (95% CI, 65 to 69). A more granular prognostic model was developed and independently validated. This model identified a new cutoff of lactate dehydrogenase at a 2.5 upper limit of normal and increasing age and presence of lung metastases as additional adverse prognostic factors. An online calculator is provided ( www.eortc.org/IGCCCG-Update ). The IGCCCG Update model improves in idual prognostication in metastatic nonseminomatous germ cell tumors. Increasing age and lung metastases add granularity to the original IGCCCG classification as adverse prognostic factors.
Evaporation of Ethanol–Water Binary Mixture Sessile Liquid Marbles
Publisher: American Chemical Society (ACS)
Date: 09-06-2016
DOI: 10.1021/ACS.LANGMUIR.6B01272
Abstract: Liquid marble is a liquid droplet coated with particles. Recently, the evaporation process of a sessile liquid marble using geometric measurements has attracted great attention from the research community. However, the lack of gravimetric measurement limits further insights into the physical changes of a liquid marble during the evaporation process. Moreover, the evaporation process of a marble containing a liquid binary mixture has not been reported before. The present paper investigates the effective density and the effective surface tension of an evaporating liquid marble that contains aqueous ethanol at relatively low concentrations. The effective density of an evaporating liquid marble is determined from the concurrent measurement of instantaneous mass and volume. Density measurements combined with surface profile fitting provide the effective surface tension of the marble. We found that the density and surface tension of an evaporating marble are significantly affected by the particle coating.
Thermally Mediated Droplet Formation at a Microfluidic T-Junction
Publisher: Bentham Science Publishers Ltd.
Date: 03-2011
Microfluidic solutions for biofluids handling in on-skin wearable systems
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2LC00993E
Abstract: The paper provides a comprehensive review on micro elastofluidic solutions for on-skin wearable devices.
Excellent Rectifying Properties of the n-3C-SiC/p-Si Heterojunction Subjected to High Temperature Annealing for Electronics, MEMS, and LED Applications
Publisher: Springer Science and Business Media LLC
Date: 18-12-2017
DOI: 10.1038/S41598-017-17985-9
Abstract: This work examines the stability of epitaxial 3C-SiC/Si heterojunctions subjected to heat treatments between 1000 °C and 1300 °C. Because of the potential for silicon carbide in high temperature and harsh environment applications, and the economic advantages of growing the 3C-SiC polytype on large diameter silicon wafers, its stability after high temperature processing is an important consideration. Yet recently, this has been thrown into question by claims that the heterojunction suffers catastrophic degradation at temperatures above 1000 °C. Here we present results showing that the heterojunction maintains excellent diode characteristics following heat treatment up to 1100 °C and while some changes were observed between 1100 °C and 1300 °C, diodes maintained their rectifying characteristics, enabling compatibility with a large range of device fabrication. The parameters of as-grown diodes were J 0 = 1 × 10 −11 A/mm 2 , n = 1.02, and +/−2V rectification ratio of 9 × 10 6 . Capacitance and thermal current-voltage analysis was used to characterize the excess current leakage mechanism. The change in diode characteristics depends on diode area, with larger areas (1 mm 2 ) having reduced rectification ratio while smaller areas (0.04 mm 2 ) maintained excellent characteristics of J 0 = 2 × 10 −10 A/mm 2 , n = 1.28, and +/−2V ratio of 3 × 10 6 . This points to localized defect regions degrading after heat treatment rather than a fundamental issue of the heterojunction.
A lab-on-a-chip for detection of nerve agent sarin in blood
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B800438B
Abstract: Sarin (C(4)H(10)FO(2)P,O-isopropyl methylphosphonofluoridate) is a colourless, odourless and highly toxic phosphonate that acts as a cholinesterase inhibitor and disrupts neuromuscular transmission. Sarin and related phosphonates are chemical warfare agents, and there is a possibility of their application in a military or terrorist attack. This paper reports a lab-on-a-chip device for detecting a trace amount of sarin in a small volume of blood. The device should allow early detection of sarin exposure during medical triage to differentiate between those requiring medical treatment from mass psychogenic illness cases. The device is based on continuous-flow microfluidics with sequential stages for lysis of whole blood, regeneration of free nerve agent from its complex with blood cholinesterase, protein precipitation, filtration, enzyme-assisted reaction and optical detection. Whole blood was first mixed with a nerve gas regeneration agent, followed by a protein precipitation step. Subsequently, the lysed product was filtered on the chip in two steps to remove particulates and fluoride ions. The filtered blood s le was then tested for trace levels of regenerated sarin using immobilised cholinesterase on the chip. Activity of immobilised cholinesterase was monitored by the enzyme-assisted reaction of a substrate and reaction of the end-product with a chromophore. Resultant changes in chromophore-induced absorbance were recorded on the chip using a Z-shaped optical window. Loss of enzyme activity obtained prior and after passage of the treated blood s le, as shown by a decrease in recorded absorbance values, indicates the presence of either free or regenerated sarin in the blood s le. The device was fabricated in PMMA (polymethylmethacrylate) using CO(2)-laser micromachining. This paper reports the testing results of the different stages, as well as the whole device with all stages in the required assay sequence. The results demonstrate the potential use of a field-deployable hand-held device for point-of-care triage of suspected nerve agent casualties.
Sensitive and fast response graphite pressure sensor fabricated by a solvent-free approach
Publisher: IEEE
Date: 10-2017
Optical measurement of flow field and concentration field inside a moving nanoliter droplet
Publisher: Elsevier BV
Date: 02-2007
Kinematics of surface acoustic wave driven liquid droplets
Publisher: ASMEDC
Date: 2011
Abstract: This paper reports the experimental characterization of a liquid droplet driven by surface acoustic wave (SAW). The SAW device was fabricated on a single-sided polished Y-cut 128° rotated lithium niobate (LiNbO3) substrate. The kinematics and deformation of the droplet was investigated at different driving voltages and droplet volumes. The kinematics of the droplet is characterized by four regimes: initial stationary state, acceleration and strong deformation, deceleration and steady motion with constant velocity. The maximum velocity of the droplet is proportional to the square of the applied voltage and does not change significantly with its volume. Bellow a critical volume, the steady velocity increases with the applied voltage. Above this volume, the steady velocity decreases with the applied voltage. In general, a larger droplet volume results in a higher steady velocity. The results from the investigation reported here can be used for optimizing the driving scheme of SAW-driven droplet-based microfuidics.
Chaotic motion of microplugs under high-frequency thermocapillary actuation
Publisher: IOP Publishing
Date: 12-12-2007
Active micromixers based on polarization instability and acoustic streaming
Publisher: ASMEDC
Date: 2011
Abstract: This paper reports two pressure-driven high-throughput active micromixers. Mixing enhancement was achieved with applied external electrical and acoustic fields. In the first active mixer, nanoporous charge-selective Nafion membrane was used to achieve strong mixing vortices. These vortices are caused by electroconvection in the concentration polarization zone above the membrane. The required applied voltage is found to be propotional to the square root of the flow rate. In the second active mixer, surface acoustic wave lauched from an interdigitated electrode deposited on a piezoelectric substrate causes acoustic streaming and improves the mixing efficiency significantly. Surface wave with a frequency of 13 MHz was launched perpendicular to the flow. The mixing efficiency was observed to be proportional to the square of the applied voltage. Compared to conventional parallel electrodes, a focusing design of the interdigitated electrode leads to a better mixing efficiency.
Magnetically mediated formation of ferrofluid emulsion
Publisher: ASMEDC
Date: 2011
Abstract: This paper reports both experimental and numerical investigations of the formation process of ferrofluid emulsion with and without an applied magnetic field. The droplets are formed in a flow-focusing and T-junction configuration. In the experiment, a homogenous magnetic field was generated using an electromagnet. The presence of the magnetic field in the flow direction affects the formation process and changes the size of the droplets. In both configurations, the change in the droplet size depends on the magnetic field strength and the flow rates. A numerical model was used to investigate the force balance during the droplet breakup process. The particle level set method was employed to capture the interface movement between the continuous fluid and the dispersed fluid. The process of the droplet formation and the flow field is discussed for both cases with and without the magnetic field. Finally, experimental and numerical results are compared. The results show that the polarity of the magnetic field does not affect the formation process.
A Micro Optofluidic System for Counting and Size Measurement of Particles
Publisher: ASMEDC
Date: 2011
Abstract: This paper reports the integration of a biconvex micro optofluidic lens into a flow cytometer. The complex optofluidic and microfluidic channel networks are integrated on a single chip. Flow cytometers are widely applied to environmental monitoring, industrial testing and biochemical studies. Integrating a fow cytometer into microfluidic networks helps to miniaturize the system and make it portable for field use. The integration of optical components, such as lenses, further improves the compactness and thus has been intensively studied recently. However, the current designs suffer from severe light scattering due to the roughness of the solid-based lens interface. In this paper, we propose a micro optofluidic system using an optofuidic liquid lens to focus the light beam. Benefting from the smooth liquid-liquid lens interface and the refractive index matching liquid as cladding streams, a light beam can be well focused without scattering. The variations of the signal peak values are reduced owing to the small beam width at the beam waist. Compared to the macroscale systems and microscale systems with solid lenses, the device presents a more efficient and accurate performance on both counting and sizing of particles. The paper reports an analytical parametric study of the lens, followed by the experimental performance of the cytometer. The cytometer was able to detect and discriminate particles with different sizes.
Carbon nanotube four-terminal devices for pressure sensing applications
Publisher: Springer International Publishing
Date: 12-2019
Sample concentration in a microfluidic paper-based analytical device using ion concentration polarization
Publisher: Elsevier BV
Date: 2016
Lab on a chip for continuous-flow magnetic cell separation
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4LC01422G
Abstract: We review the fundamental physics in continuous-flow magnetic cell separation and identify the optimisation parameters of LOC devices.
Double spiral detection channel for on-chip chemiluminescence detection
Publisher: Elsevier BV
Date: 07-2012
Wide bandgap semiconductor nanomembranes as a long-term bio-interface for flexible, implanted neuromodulator
Publisher: Research Square Platform LLC
Date: 28-01-2022
DOI: 10.21203/RS.3.RS-1305833/V1
Abstract: Electrical neuron stimulation holds promise for the treatment of several chronic neurological disorders, including spinal cord injury, epilepsy, and Parkinson’s disease. The implementation of ultrathin, flexible electrodes, that can offer non-invasive attachment to soft neural tissues, is a breakthrough technology for timely, continuous, programable, and spatial stimulations. However, to enable flexibility in neural electrodes, the conventional thick and bulky ceramic package is no longer applicable to soft electronics, which poses several technical issues such as device degradation and long-term stability. We introduce herein a new concept of long-lived flexible neural electrodes using silicon carbide nanomembranes as the Faradaic interface, and thermal oxide thin films as the electrical isolation layer. The silicon carbide (SiC) membranes were developed using a wafer-level chemical deposition process while thermal oxide was grown employing a standard and high-quality wet oxidation approach, which are scalable and compatible with industrial microelectronic technologies. Our experimental results showed excellent stability in the SiC/SiO 2 hybrid system that can potentially last several decades with maintained reliable electrical properties in biofluid environments. We demonstrated the capability of our material system in stimulating peripheral nerves (i.e., sciatic nerve) in rat models, showing comparable muscle contraction response recorded from electromyogram (EMG) stimulation results to a gold-standard non-implanted nerve stimulation device. The design concept, scalable fabrication approach, and the multimodal functionalities in SiC/SiO 2 flexible electronics open an exciting possibility for fundamental neuroscience studies as well as clinical neural stimulation-based therapy.
A lab-on-a-chip device for investigating the fusion process of olfactory ensheathing cell spheroids
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6LC00815A
Abstract: We report a lab-on-a-chip device for trapping and fusion of three-dimensional spheroids that assist transplantation therapy.
Cryoprotectant-Free Freezing of Cells Using Liquid Marbles Filled with Hydrogel
Publisher: American Chemical Society (ACS)
Date: 26-11-2018
Abstract: Cryopreservation without cryoprotectant remains a significant challenge for the re-establishment of cell culture after freeze-thaw. Thus, finding an alternative and a simple cryopreservation method is necessary. Liquid marble (LM)-based digital microfluidics is a promising approach for cryoprotectant-free cryopreservation. However, the use of this platform to efficiently preserve s les with low cell density and well-controlled serum concentrations has not been investigated. We addressed this issue by embedding an agarose-containing fetal bovine serum (FBS) inside the LM. A low density of 500 cells/μL of murine 3T3 cells was selected for evaluating the postcryogenic survivability. The effects on the post-thaw cell viability of the concentration of agarose, the amount of FBS inside the agarose, and the volume of the LM were investigated systematically. This paper also presents an analysis on the changes in shape and crack size of post-thawed agarose. The results revealed that the embedded agarose gel serves as a controlled release mechanism of FBS and significantly improves cell viability. Post-thaw recovery sustains major cellular features, such as viability, cell adhesion, and morphology. The platform technology reported here opens up new possibilities to cryopreserve rare biological s les without the toxicity risk of cryoprotectants.
Survival and New Prognosticators in Metastatic Seminoma: Results From the IGCCCG-Update Consortium
Publisher: American Society of Clinical Oncology (ASCO)
Date: 10-05-2021
DOI: 10.1200/JCO.20.03292
Abstract: The classification of the International Germ-Cell Cancer Collaborative Group (IGCCCG) has been a major advance in the management of germ-cell tumors, but relies on data of only 660 patients with seminoma treated between 1975 and 1990. We re-evaluated this classification in a database from a large international consortium. Data on 2,451 men with metastatic seminoma treated with cisplatin- and etoposide-based first-line chemotherapy between 1990 and 2013 were collected from 30 institutions or collaborative groups in Australia, Europe, and North America. Clinical trial and registry data were included. Primary end points were progression-free survival (PFS) and overall survival (OS) calculated from day 1 of treatment. Variables at initial presentation were evaluated for their prognostic impact. Results were validated in an independent validation set of 764 additional patients. Compared with the initial IGCCCG classification, in our modern series, 5-year PFS improved from 82% to 89% (95% CI, 87 to 90) and 5-year OS from 86% to 95% (95% CI, 94 to 96) in good prognosis, and from 67% to 79% (95% CI, 70 to 85) and 72% to 88% (95% CI, 80 to 93) in intermediate prognosis patients. Lactate dehydrogenase (LDH) proved to be an additional adverse prognostic factor. Good prognosis patients with LDH above 2.5× upper limit of normal had a 3-year PFS of 80% (95% CI, 75 to 84) and a 3-year OS of 92% (95% CI, 88 to 95) versus 92% (95% CI, 90 to 94) and 97% (95% CI, 96 to 98) in the group with lower LDH. PFS and OS in metastatic seminoma significantly improved in our modern series compared with the original data. The original IGCCCG classification retains its relevance, but can be further refined by adding LDH at a cutoff of 2.5× upper limit of normal as an additional adverse prognostic factor.
Optofluidic variable optical attenuator
Publisher: IEEE
Date: 2010
Instability of pressure driven viscous fluid streams in a microchannel under a normal electric field
Publisher: Elsevier BV
Date: 11-2012
Self-sensing paper-based actuators employing ferromagnetic nanoparticles and graphite
Publisher: AIP Publishing
Date: 03-04-2017
DOI: 10.1063/1.4979701
Abstract: Paper-based microfluidics and sensors have attracted great attention. Although a large number of paper-based devices have been developed, surprisingly there are only a few studies investigating paper actuators. To fulfill the requirements for the integration of both sensors and actuators into paper, this work presents an unprecedented platform which utilizes ferromagnetic particles for actuation and graphite for motion monitoring. The use of the integrated mechanical sensing element eliminates the reliance on image processing for motion detection and also allows real-time measurements of the dynamic response in paper-based actuators. The proposed platform can also be quickly fabricated using a simple process, indicating its potential for controllable paper-based lab on chip.
Efficient and low-complexity image coding with the lifting scheme and modified SPIHT
Publisher: IEEE
Date: 06-0001
A Procedure for Encapsulation in Microchannel
Publisher: ASMEDC
Date: 2007
DOI: 10.1115/HT2007-32522
Abstract: A fixed-grid approach for modeling the motion of a particle-encapsulated droplet carried by a pressure driven immiscible carrier fluid in a microchannel is presented. Three phases (the carrier fluid, the droplet and the particle), and two different moving boundaries (the droplet-carrier fluid and droplet-particle interfaces), are involved. This is a moving boundaries problem with the motion of the three phases strongly coupled. In the present article, the particle is assumed to be a fluid of high viscosity and constrained to move with rigid body motion. A combined formulation using one set of governing equations to treat the three phases is employed. The droplet-carrier fluid interface is represented and evolved using a level-set method with a mass correction scheme. Surface tension is modeled using the Continuum Surface Force model. An additional signed distance function is employed to define the droplet-particle interface. Its evolution is determined from the particle motion governed by the Newton-Euler equations. The governing equations are solved numerically using a Finite Volume method on a fixed Cartesian grid. For demonstration purpose, the flows of particle-encapsulated droplets through a constricted microchannel and through a microchannel system are presented.
An amplification-free electrochemical detection of exosomal miRNA-21 in serum samples
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7AN01843F
Abstract: A sensitive and lification-free assay for the electrochemical detection of exosomal miRNAs in complex biological s les.
Gold-Loaded Nanoporous Ferric Oxide Nanocubes with Peroxidase-Mimicking Activity for Electrocatalytic and Colorimetric Detection of Autoantibody
Publisher: American Chemical Society (ACS)
Date: 26-09-2017
DOI: 10.1021/ACS.ANALCHEM.7B02880
Abstract: The enzyme-mimicking activity of iron oxide based nanostructures has provided a significant advantage in developing advanced molecular sensors for biomedical and environmental applications. Herein, we introduce the horseradish peroxidase (HRP)-like activity of gold-loaded nanoporous ferric oxide nanocubes (Au-NPFe
Stretchable Inertial Microfluidic Device for Tunable Particle Separation
Publisher: American Chemical Society (ACS)
Date: 06-08-2020
A polymeric cell stretching device for real-time imaging with optical microscopy
Publisher: Springer Science and Business Media LLC
Date: 19-07-2013
DOI: 10.1007/S10544-013-9796-2
Abstract: This paper reports the design, fabrication and characterization of a cell stretching device based on the side stretching approach. Numerical simulation using finite element method provides a guideline for optimizing the geometry and maximizing the output strain of the stretched membrane. An unique PDMS-based micro fabrication process was developed for obtaining high parallelization, well controlled membrane thickness and an ultra-thin bottom layer that is crucial for the use with confocal microscopes. The stretching experiments are fully automated with both device actuation and image acquisition. A programmable pneumatic control system was built for simultaneous driving of 24 stretching arrays. The actuation signals are synchronized with the image acquisition system to obtain time-lapse recording of cells grown on the stretched membrane. Experimental results verified the characteristics predicted by the simulation. A platform with 15 stretching units was integrated on a standard 24 mm × 50 mm glass slide. Each unit can achieve a maximum strain of more than 60 %. The platform was tested for cell growth under cyclic stretching. The preliminary results show that the device is compatible with all standard microscopes.
Ultra-Sensitive OPTO-Piezoresistive Sensors Utilising 3C-SiC/Si Heterostructures
Publisher: IEEE
Date: 06-2019
A hot-film air flow sensor for elevated temperatures
Publisher: AIP Publishing
Date: 2019
DOI: 10.1063/1.5065420
Abstract: We report a novel packaging and experimental technique for characterizing thermal flow sensors at high temperatures. This paper first reports the fabrication of 3C-SiC (silicon carbide) on a glass substrate via anodic bonding, followed by the investigation of thermoresistive and Joule heating effects in the 3C-SiC nano-thin film heater. The high thermal coefficient of resistance of approximately −20 720 ppm/K at ambient temperature and −9287 ppm/K at 200 °C suggests the potential use of silicon carbide for thermal sensing applications in harsh environments. During the Joule heating test, a high-temperature epoxy and a brass metal sheet were utilized to establish the electric conduction between the metal electrodes and SiC heater inside a temperature oven. In addition, the metal wires from the sensor to the external circuitry were protected by a fiberglass insulating sheath to avoid short circuit. The Joule heating test ensured the stability of mechanical and Ohmic contacts at elevated temperatures. Using a hot-wire anemometer as a reference flow sensor, calibration tests were performed at 25 °C, 35 °C, and 45 °C. Then, the SiC hot-film sensor was characterized for a range of low air flow velocity, indicating a sensitivity of 5 mm−1 s. The air flow was established by driving a metal propeller connected to a DC motor and controlled by a microcontroller. The materials, metallization, and interconnects used in our flow sensor were robust and survived temperatures of around 200 °C.
An electrokinetically tunable optofluidic bi-concave lens
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2LC40406K
Abstract: This paper numerically and experimentally investigates and demonstrates the design of an optofluidic in-plane bi-concave lens to perform both light focusing and erging using the combined effect of pressure driven flow and electro-osmosis. The concave lens is formed in a rectangular chamber with a liquid core-liquid cladding (L(2)) configuration. Under constant flow rates, the performance of the lens can be controlled by an external electric field. The lens consists of a core stream (conducting fluid), cladding streams (non-conducing fluids), and auxiliary cladding streams (conducting fluids). In the focusing mode, the auxiliary cladding stream is introduced to sandwich the biconcave lens to prevent light rays from scattering at the rough chamber wall. In the erging mode, the auxiliary cladding liquid has a new role as the low refractive-index cladding of the lens. In the experiments, the test devices were fabricated in polydimethylsiloxane (PDMS) using the standard soft lithography technique. Ethanol, cinnamaldehyde, and a mixture of 73.5% ethylene glycol and 26.5% ethanol work as the core stream, cladding streams and auxiliary cladding streams. In the numerical simulation, the electric force acts as a body force. The governing equations are solved by a finite volume method on a Cartesian fixed staggered grid. The evolution of the interface was captured by the level set method. The results show that the focal length in the focusing mode and the ergent angle of the light beam in the erging mode can be tuned by adjusting the external electric field at fixed flow rates. The numerical results have a reasonable agreement with the experimental results.
Three-dimensional printing of biological matters
Publisher: Elsevier BV
Date: 03-2016
Ferrofluids for heat transfer enhancement under an external magnetic field
Publisher: Elsevier BV
Date: 08-2018
Formation of core–shell droplets for the encapsulation of liquid contents
Publisher: Research Square Platform LLC
Date: 23-08-2021
DOI: 10.21203/RS.3.RS-835459/V1
Abstract: Accurate control of monodisperse core-shell droplets generated in a microfluidic device has a broad range of applications in research and industry. This paper reports the experimental investigation of flow-focusing microfluidic devices capable of producing size-tuneable and monodisperse core-shell droplets. The dimension of the core-shell droplets was controlled passively by the channel geometry and the flow rate of the liquid phases. The results indicate that microchannel geometry is more significant than flow rates. The highly controllable core-shell droplets could be subsequently employed as a template for generating core-shell micropaticles with liquid core. Optical, electron microscopy and X-ray computed microtomography showed that the geometry of the core-shell droplets remains unchanged after solidification, drying and collection. The present study also looks at the thermal stability of core-shell particles depending on the particle size. The larger core-shell partcles with a thicker shell provide a higher resistance to heating at elevated temperature. The high degree of control with a flow-focusing microfluidic device makes this a promising approach for the encapsulation, storage, and delivery of lipophilic contents.
Ultra-high strain in epitaxial silicon carbide nanostructures utilizing residual stress amplification
Publisher: AIP Publishing
Date: 03-04-2017
DOI: 10.1063/1.4979834
Abstract: Strain engineering has attracted great attention, particularly for epitaxial films grown on a different substrate. Residual strains of SiC have been widely employed to form ultra-high frequency and high Q factor resonators. However, to date, the highest residual strain of SiC was reported to be limited to approximately 0.6%. Large strains induced into SiC could lead to several interesting physical phenomena, as well as significant improvement of resonant frequencies. We report an unprecedented nanostrain- lifier structure with an ultra-high residual strain up to 8% utilizing the natural residual stress between epitaxial 3C-SiC and Si. In addition, the applied strain can be tuned by changing the dimensions of the lifier structure. The possibility of introducing such a controllable and ultra-high strain will open the door to investigating the physics of SiC in large strain regimes and the development of ultra sensitive mechanical sensors.
An air-breathing microfluidic formic acid fuel cell with a porous planar anode: experimental and numerical investigations
Publisher: IOP Publishing
Date: 03-09-2010
Enhanced Blood Plasma Extraction Utilising Viscoelastic Effects in a Serpentine Microchannel.
Publisher: MDPI AG
Date: 14-02-2022
DOI: 10.3390/BIOS12020120
Abstract: Plasma extraction from blood is essential for diagnosis of many diseases. The critical process of plasma extraction requires removal of blood cells from whole blood. Fluid viscoelasticity promotes cell migration towards the central axis of flow due to differences in normal stress and physical properties of cells. We investigated the effects of altering fluid viscoelasticity on blood plasma extraction in a serpentine microchannel. Poly (ethylene oxide) (PEO) was dissolved into blood to increase its viscoelasticity. The influences of PEO concentration, blood dilution, and flow rate on the performance of cell focusing were examined. We found that focusing performance can be significantly enhanced by adding PEO into blood. The optimal PEO concentration ranged from 100 to 200 ppm with respect to effective blood cell focusing. An optimal flow rate from 1 to 15 µL/min was determined, at least for our experimental setup. Given less than 1% haemolysis was detected at the outlets in all experimental combinations, the proposed microfluidic methodology appears suitable for applications sensitive to haemocompatibility.
CONVECTIVE HEAT TRANSFER CHARACTERISTICS OF AQUEOUS TiO2 NANOFLUID UNDER LAMINAR FLOW CONDITIONS
Publisher: World Scientific Pub Co Pte Lt
Date: 12-2008
DOI: 10.1142/S0219581X08005493
Abstract: This paper reports an experimental investigation into force convective heat transfer of nanofluids flowing through a cylindrical minichannel under laminar flow and constant wall heat flux conditions. S le nanofluids were prepared by dispersing different volumetric concentrations (0.2–0.8%) of nanoparticles in deionized water. The results showed that both the convective heat transfer coefficient and the Nusselt number of the nanofluid increase considerably with the nanoparticle volume fraction as well as the Reynolds number. Along with the enhanced thermal conductivity of nanofluids, the migration, interactions, and Brownian motion of nanoparticles and the resulting disturbance of the boundary layer are responsible for the observed enhancement of heat transfer coefficients of nanofluids.
Protein array processing software for automated semiquantitative analysis of serum antibody repertoires
Publisher: AIP Publishing
Date: 09-2023
DOI: 10.1063/5.0169421
A Versatile Sacrificial Layer for Transfer Printing of Wide Bandgap Materials for Implantable and Stretchable Bioelectronics
Publisher: Wiley
Date: 04-09-2020
Thermally mediated control of liquid microdroplets at a bifurcation
Publisher: IOP Publishing
Date: 02-03-2009
Strain Effect in Highly‐Doped n‐Type 3C‐SiC‐on‐Glass Substrate for Mechanical Sensors and Mobility Enhancement
Publisher: Wiley
Date: 22-07-2018
High-throughput micromixers based on acoustic streaming induced by surface acoustic wave
Publisher: Springer Science and Business Media LLC
Date: 10-2011
Negative magnetophoresis in diluted ferrofluid flow
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5LC00427F
Abstract: We report separation and mixing phenomena induced by negative magnetophoresis in a circular chamber.
Magnetic actuation for microfluidics based on ferrofluid droplets - art. no. 64140T
Publisher: SPIE
Date: 27-12-2007
DOI: 10.1117/12.696494
Dynamic behaviours of monodisperse double emulsion formation in a tri-axial capillary device
Publisher: Research Square Platform LLC
Date: 29-09-2022
DOI: 10.21203/RS.3.RS-2110258/V1
Abstract: We investigated experimentally, analytically and numerically the formation process of double emulsion formations under dripping regime in a tri-axial co-flow capillary device. The results show that mismatches of core and shell droplets under a given flow condition can be captured both experimentally and numerically. We propose a semi-analytical model using the match ratio between the pinch-off length of the shell droplet and the product of the core growth rate and its pinch-off time. The mismatch issue can be avoided if the match ratio is lower than unity. We considered a model with the wall effect to predict the size of the matched double emulsion. The model shows slight deviations with experimental data if the Reynolds number of continuous phase is lower than 0.06, but asymptotically approaches to good agreement if the Reynolds number increases from 0.06 to 0.14. The numerical simulation generally agrees with the experiments under various flow conditions.
Gold-loaded nanoporous iron oxide nanocubes: A novel dispersible capture agent for tumor-associated autoantibody analysis in serum
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7NR03006A
Abstract: An electrochemical and colorimetric method for detecting autoantibodies using gold-loaded nanoporous Fe 2 O 3 nanocubes as capture agents is reported for the first time.
A bisulfite treatment and PCR-free global DNA methylation detection method using electrochemical enzymatic signal engagement
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.BIOS.2018.10.020
Abstract: In this paper we report on a bisulfite treatment and PCR lification-free method for sensitive and selective quantifying of global DNA methylation. Our method utilizes a three-step strategy that involves (i) initial isolation and denaturation of global DNA using the standard isolation protocol and direct adsorption onto a bare gold electrode via gold-DNA affinity interaction, (ii) selective interrogation of methylation sites in adsorbed DNA via methylation-specific 5mC antibody, and (iii) subsequent signal enhancement using an electrochemical-enzymatic redox cycling reaction. In the redox cycling reaction, glucose oxidase (GO
Particle inertial focusing and its mechanism in a serpentine microchannel
Publisher: Springer Science and Business Media LLC
Date: 13-12-2013
Silicon micro-/nanomachining and applications
Publisher: Springer International Publishing
Date: 29-10-2017
Nanoarchitecture Frameworks for Electrochemical miRNA Detection
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.TIBS.2018.11.012
Abstract: With revolutionary advances in next-generation sequencing, the human transcriptome has been comprehensively interrogated. These discoveries have highlighted the emerging functional and regulatory roles of a large fraction of RNAs suggesting the potential they might hold as stable and minimally invasive disease biomarkers. Although a plethora of molecular-biology- and biosensor-based RNA-detection strategies have been developed, clinical application of most of these is yet to be realized. Multifunctional nanomaterials coupled with sensitive and robust electrochemical readouts may prove useful in these applications. Here, we summarize the major contributions of engineered nanomaterials-based electrochemical biosensing strategies for the analysis of miRNAs. With special emphasis on nanostructure-based detection, this review also chronicles the needs and challenges of miRNA detection and provides a future perspective on the presented strategies.
Active control for droplet-based microfluidics
Publisher: SPIE
Date: 27-12-2006
DOI: 10.1117/12.696496
Picking up and placing a liquid marble using dielectrophoresis
Publisher: Springer Science and Business Media LLC
Date: 21-11-2018
Stretchable, Skin-Breathable, and Ultrasensitive Respiration Sensor Using Graphite on Paper With Smart Structures
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2022
Advances in piezoelectric thin films for acoustic biosensors, acoustofluidics and lab-on-chip applications
Publisher: Elsevier BV
Date: 08-2017
Manipulation of a droplet in a planar channel by periodic thermocapillary actuation
Publisher: IOP Publishing
Date: 14-03-2008
Optical detection for droplet size control in microfluidic droplet-based analysis systems
Publisher: Elsevier BV
Date: 10-2006
Micromachines Beyond Silicon-Based Technologies: A Letter from the New Editor-in-Chief
Publisher: MDPI AG
Date: 09-03-2016
DOI: 10.3390/MI7030044
Long-Lived, Transferred Crystalline Silicon Carbide Nanomembranes for Implantable Flexible Electronics
Publisher: American Chemical Society (ACS)
Date: 21-08-2019
Abstract: Implantable electronics are of great interest owing to their capability for real-time and continuous recording of cellular-electrical activity. Nevertheless, as such systems involve direct interfaces with surrounding biofluidic environments, maintaining their long-term sustainable operation, without leakage currents or corrosion, is a daunting challenge. Herein, we present a thin, flexible semiconducting material system that offers attractive attributes in this context. The material consists of crystalline cubic silicon carbide nanomembranes grown on silicon wafers, released and then physically transferred to a final device substrate (
A Microfluidic Method for Investigating Ion-Specific Bubble Coalescence in Salt Solutions
Publisher: American Chemical Society (ACS)
Date: 24-10-2016
DOI: 10.1021/ACS.LANGMUIR.6B03266
Abstract: This paper reports the direct and precise measurement of bubble coalescence in salt solutions using microfluidics. We directly visualized the bubble coalescence process in a microchannel using high-speed imaging and evaluated the shortest coalescence time to determine the transition concentration of sodium halide solutions. We found the transition concentration is ion-specific, and the capacity of sodium halide salts to inhibit bubble coalescence follows the order of NaF > NaCl > NaBr > NaI. The microfluidic method overcomes the inherent uncertainties in conventional large-scale devices and methods.
Loop-mediated isothermal amplification in a core-shell bead assay for the detection of tyrosine kinase axl overexpression
Publisher: MDPI AG
Date: 30-07-2021
DOI: 10.3390/MI12080905
Abstract: The upregulated expression of tyrosine kinase AXL has been reported in several hematologic and solid human tumors, including gastric, breast, colorectal, prostate and ovarian cancers. Thus, AXL can potentially serve as a diagnostic and prognostic biomarker for various cancers. This paper reports the first ever loop-mediated isothermal lification (LAMP) in a core-shell bead assay for the detection of AXL gene overexpression. We demonstrated simple instrumentation toward a point-of-care device to perform LAMP. This paper also reports the first ever use of core-shell beads as a microreactor to perform LAMP as an attempt to promote environmentally-friendly laboratory practices.
Active micromixers
Publisher: Elsevier
Date: 2012
Heat transfer in plug flow in cylindrical microcapillaries with constant surface heat flux
Publisher: Elsevier BV
Date: 02-2013
Air-breathing membraneless laminar flow-based fuel cell with flow-through anode
Publisher: Elsevier BV
Date: 02-2012
Modelling Sessile Droplet Profile Using Asymmetrical Ellipses
Publisher: MDPI AG
Date: 20-11-2021
DOI: 10.3390/PR9112081
Abstract: Modelling the profile of a liquid droplet has been a mainstream technique for researchers to study the physical properties of a liquid. This study proposes a facile modelling approach using an elliptic model to generate the profile of sessile droplets, with MATLAB as the simulation environment. The concept of the elliptic method is simple and easy to use. Only three specific points on the droplet are needed to generate the complete theoretical droplet profile along with its critical parameters such as volume, surface area, height, and contact radius. In addition, we introduced fitting coefficients to accurately determine the contact angle and surface tension of a droplet. Droplet volumes ranging from 1 to 300 µL were chosen for this investigation, with contact angles ranging from 90° to 180°. Our proposed method was also applied to images of actual water droplets with good results. This study demonstrates that the elliptic method is in excellent agreement with the Young–Laplace equation and can be used for rapid and accurate approximation of liquid droplet profiles to determine the surface tension and contact angle.
Integrated flow sensor for in situ measurement and control of acoustic streaming in flexural plate wave micropumps
Publisher: Elsevier BV
Date: 02-2000
Air-breathing microfluidic fuel cell with fuel reservoir
Publisher: Elsevier BV
Date: 07-2012
Micro elastofluidics: Elasticity and flexibility for efficient microscale liquid handling
Publisher: MDPI AG
Date: 14-11-2020
DOI: 10.3390/MI11111004
Abstract: Microfluidics is the science and technology around the behaviour of fluid and fluid flow at the microscale [...]
Modelling and optimization of micro optofluidic lenses
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B819158A
Abstract: This paper reports the modelling and experimental results of a liquid-core liquid-cladding optofluidic lens. The lens is based on three laminar streams in a circular chamber. The stream lines and the curvature of the interface can be predicted accurately using the theory of two-dimensional dipole flow in a circularly bounded domain. The model establishes basic relations between the flow rate ratio of the core/cladding streams and the radius of curvature and consequently the focal length of the lens. Compared to a rectangular chamber, this new circular design allows the formation of a liquid-core liquid-cladding lens with perfect curvatures. The circular design allows tuning a perfect curvature ranging from the chamber radius itself to infinity. The test device with a circular lens chamber with 1 mm diameter and 50 microm height was fabricated in PDMS. The lens shape as well as the stream lines were characterized using fluorescent dye and tracing particles. Experimental results agree well with the analytical results predicted by the model.
Liquid Marbles as Miniature Reactors for Chemical and Biological Applications
Publisher: MDPI AG
Date: 07-07-2020
DOI: 10.3390/PR8070793
Abstract: The need for miniaturised reaction systems has led to the development of various microreactor platforms, such as droplet-based microreactors. However, these microreactors possess inherent drawbacks, such as rapid evaporation and difficult handling, that limit their use in practical applications. Liquid marbles are droplets covered with hydrophobic particles and are a potential platform that can overcome the weaknesses of bare droplets. The coating particles completely isolate the interior liquids from the surrounding environment, thus conveniently encapsulating the reactions. Great efforts have been made over the past decade to demonstrate the feasibility of liquid marble-based microreactors for chemical and biological applications. This review systemically summarises state-of-the-art implementations of liquid marbles as microreactors. This paper also discusses the various aspects of liquid marble-based microreactors, such as the formation, manipulation, and future perspectives.
Functional Microarray Platform with Self-Assembled Monolayers on 3C-Silicon Carbide
Publisher: American Chemical Society (ACS)
Date: 26-10-2020
Magnetic digital microfluidics – a review
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7LC00025A
Abstract: A magnetic digital microfluidic platform manipulates droplets on an open surface.
Thermoresistance of p-Type 4H–SiC Integrated MEMS Devices for High-Temperature Sensing
Publisher: Wiley
Date: 02-01-2019
Thermomagnetic Convection Around a Current-Carrying Wire in Ferrofluid
Publisher: ASME International
Date: 23-05-2017
DOI: 10.1115/1.4036688
Abstract: Thermomagnetic convection of a ferrofluid flow induced by the internal magnetic field around a vertical current-carrying wire was theoretically analyzed and experimentally validated for the first time. The Nusselt number for a heated 50-μm diameter wire in a ferrofluid was measured for different electrical currents and fluid temperatures. The experimental results are in a good agreement with the proposed scaling analysis. We found that increasing the current will increase the Nusselt number nonlinearly and ultimately enhances the heat transfer capability of the induced ferrofluid flow. We observed that the thermomagnetic convection becomes dominant, if large enough currents are applied.
Micromixer based on viscoelastic flow instability at low Reynolds number
Publisher: AIP Publishing
Date: 03-2009
DOI: 10.1063/1.3108462
Fluid Mechanics of Flow Through Rectangular Hydrophobic Microchannels
Publisher: ASMEDC
Date: 2011
Abstract: In this study, the effect of two important parameters have been evaluated for pressure driven liquid flows in microchannel in laminar regime by analytical modeling, followed by experimental measurement. These parameters are wettability conditions of microchannel surfaces and aspect ratio of rectangular microchannels. For small values of aspect ratio, the channel was considered to have a rectangular cross-section, instead of being two parallel plates. Novel expressions for these kinds of channels were derived using eigenfunction expansion method. The obtained two-dimensional solutions based on dual finite series were then extended to the case of a constant slip velocity at the bottom wall. In addition, for large values of aspect ratio, a general equation was obtained which is capable of accounting for different values of slip lengths for both upper and lower channel walls. Firstly, it was found out that for low aspect ratio microchannels, the results obtained by analytical rectangular 2-D model agree well with the experimental measurements as compared to one dimensional solution. For high aspect ratio microchannels, both models predict the same trend. This finding indicates that using the conventional 1-D solution may not be accurate for the channels where the width is of the same order as the height. Secondly, experimental results showed that up to 2.5% and 16% drag reduction can be achieved for 1000 and 250 micron channel height, respectively. It can be concluded that increasing the surface wettability can reduce the pressure drop in laminar regime and the effect is more pronounced by decreasing the channel height.
Air-breathing membraneless laminar flow fuel cell with flow-through anode
Publisher: ASMEDC
Date: 2011
DOI: 10.1115/FUELCELL2011-54918
Abstract: This paper reports the fabrication and characterization of a new concept of flow-through anode for membraneless laminar flow fuel cell (LFFC). To establish a reference case, a fuel cell with flow over and planar anode was fabricated as well. Experimental results indicated that maximum power density was improved from 17 mW/cm2 in planar design to 23 mW/cm2 using the flow-through design. The higher power density of flow-through design is an indicative of higher fuel utilization in the porous anode. Images of the flow obtained experimentally showed that mixing was reduced at the liquid-liquid interface in the channel with flow-through anode leading to increased fuel concentration over anode.
Fabrication and Experimental Characterization of Nanochannels
Publisher: ASME International
Date: 13-04-2012
DOI: 10.1115/1.4005702
Abstract: Nanofluidics is the science and technology involving a fluid flowing in or around structures with a least one dimension in the nanoscale, which is defined as the range from 1 nm to 100 nm. In this paper, we present the fabrication and characterization of nanochannels in silicon and glass. Since the lateral dimension of the channels is limited by the wavelength of UV light used in photolithography, the channel width can only be fabricated in the micrometer scale. However, the depth of the channel can be controlled precisely by the etching rate of reactive ion etching (RIE). Microchannels and access holes were etched with deep reactive ion etching (DRIE). Both nanochannels and microchannels were sealed by a Pyrex glass wafer using anodic bonding. The fabricated nanochannels were characterized by capillary filling and evaporation experiments. Due to the small channel height and weak fluorescent signal, fluorescent techniques are not suitable for the characterization of the nanochannels. A long exposure time is needed because of the limited amount of fluorescent molecules inhibit the measurement of transient and dynamic processes. However, as the channel height is shorter than all visible wavelengths, the contrast in refractive indices of air and liquid allows clear visualization of nanochannels filled with liquids. Automatic image processing with matlab allows the evaluation of capillary filling in nanochannels. Interesting phenomena and discrepancies with conventional theories were observed.
Mechanobiology in cardiology: Micro‐ and nanotechnologies to probe mechanosignaling
Publisher: Wiley
Date: 12-01-2021
DOI: 10.1002/VIW.20200080
Re‐Entrant Microstructures for Robust Liquid Repellent Surfaces
Publisher: Wiley
Date: 03-02-2023
Abstract: Superhydrophobic surfaces have many interesting applications because of their self‐cleaning, waterproof, anti‐biofouling, anti‐corrosion, and low‐adhesion properties. Accordingly, numerous surfaces with hierarchical micro/nanostructures are designed and engineered to achieve superhydrophobicity. However, these surfaces have two major problems. First, they lose superhydrophobic properties over time, primarily because of environmental conditions such as vibration, external pressure, evaporation, and pollution. Second, most superhydrophobic surfaces fail to repel all types of liquids, especially those with low surface tensions. To address this bottleneck, microstructures with re‐entrant curvature have emerged, demonstrating excellent liquid‐repellent abilities and robustness. Additionally, microstructures with re‐entrant curvature have significant applications in designing surfaces with unidirectional wetting properties for passive liquid handling. Accordingly, this review systematically summarizes the design and fabrication strategies of these re‐entrant microstructures. The emphasis is given to wettability studies and other surface properties of re‐entrant microstructures and their applications, especially for liquid self‐transporting. This paper also highlights the potential applications and remaining technical challenges of fabricating these structures. Finally, the study is concluded by providing the future directions in this promising field.
Magnetically-Actuated Mixing and Merging of Acid-Base Micro-Droplets on Open Surfaces: Preliminary Study
Publisher: MDPI AG
Date: 06-2018
DOI: 10.3390/S18061767
Hydrodynamic focusing in microchannels under consideration of diffusive dispersion: theories and experiments
Publisher: Elsevier BV
Date: 06-2005
Improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids
Publisher: AIP Publishing
Date: 08-07-2008
DOI: 10.1063/1.2959099
Abstract: This paper reports the improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids. Since rectification in a diffuser/nozzle structure with Newtonian fluids is caused by inertial effects, micropumps based on this concept require a relatively high Reynolds numbers and high pumping frequencies. In applications with relatively low Reynolds numbers, anisotropic behavior can be achieved with viscoelastic effects. In our investigations, a solution of dilute polyethylene oxide was used as the viscoelastic fluid. A microfluidic device was fabricated in silicon using deep reactive ion etching. The microfluidic device consists of access ports for pressure measurement, and a series of ten diffuser/nozzle structures. Measurements were carried out for diffuser/nozzle structures with opening angles ranging from 15° to 60°. Flow visualization, pressure drop and diodicity of de-ionized water and the viscoelastic fluid were compared and discussed. The improvement of diodicity promises a simple pumping concept at low Reynolds numbers for lab-on-a-chip applications.
Thermal flow sensor for ultra-low velocities based on printed circuit board technology
Publisher: IOP Publishing
Date: 06-11-2001
Nano strain-amplifier: Making ultra-sensitive piezoresistance in nanowires possible without the need of quantum and surface charge effects
Publisher: AIP Publishing
Date: 19-09-2016
DOI: 10.1063/1.4963258
Abstract: This paper presents an innovative nano strain- lifier employed to significantly enhance the sensitivity of piezoresistive strain sensors. Inspired from the dogbone structure, the nano strain- lifier consists of a nano thin frame released from the substrate, where nanowires were formed at the centre of the frame. Analytical and numerical results indicated that a nano strain- lifier significantly increases the strain induced into a free standing nanowire, resulting in a large change in their electrical conductance. The proposed structure was demonstrated in p-type cubic silicon carbide nanowires fabricated using a top down process. The experimental data showed that the nano strain- lifier can enhance the sensitivity of SiC strain sensors at least 5.4 times larger than that of the conventional structures. This result indicates the potential of the proposed strain- lifier for ultra-sensitive mechanical sensing applications.
Negative Pressure Induced Droplet Generation in a Microfluidic Flow-Focusing Device
Publisher: American Chemical Society (ACS)
Date: 16-02-2017
DOI: 10.1021/ACS.ANALCHEM.6B05053
Abstract: We introduce an effective method to actively induce droplet generation using negative pressure. Droplets can be generated on demand using a series of periodic negative pressure pulses. Fluidic network models were developed using the analogy to electric networks to relate the pressure conditions for different flow regimes. Experimental results show that the droplet volume is correlated to the pressure ratio with a power law of 1.3. Using a pulsed negative pressure at the outlet, we are able to produce droplets in demand and with a volume proportional to the pulse width.
Flexible and multifunctional electronics fabricated by a solvent-free and user-friendly method
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA14646E
Abstract: Pencil-drawn flexible and multifunctional electronic devices have been proven to show potential for various applications including mass and flow sensors, human-motion detection and wearable thermal therapy.
Micro-magnetofluidics: interactions between magnetism and fluid flow on the microscale
Publisher: Springer Science and Business Media LLC
Date: 16-11-2012
Conoscopic analysis of electric field driven planar aligned nematic liquid crystal
Publisher: The Optical Society
Date: 23-04-2014
DOI: 10.1364/AO.53.002773
Nanofluidic devices and their applications
Publisher: American Chemical Society (ACS)
Date: 06-03-2008
DOI: 10.1021/AC702296U
Abstract: Recent developments in micro- and nanotechnologies made possible the fabrication of devices integrating a deterministic network of nanochannels, i.e., with at least one dimension in a range from 1 to 100 nm. The proximity of this dimension and the Debye length, the size of biomolecules such as DNA or proteins, or even the slip length, added to the excellent control on the geometry gives unique features to nanofluidic devices. This new class of devices not only finds applications wherever less well-defined porous media, such as electrophoresis gels, have been traditionally used but also give a new insight into the sieving mechanisms of biomolecules and the fluid flow at the nanoscale. Beyond this, the control on the geometry allows smarter design resulting, among others, in new separation principles by taking advantage of the anisotropy. This perspective gives an overview on the fabrication technologies of nanofluidic devices and their applications. In the first part, the current state of the art of nanofluidic fabrication is presented. The second part first discusses the key transport phenomena in nanochannels. Current applications of nanofluidic devices are next discussed. Finally, future challenges and possible applications are highlighted.
Hybrid-assembled micro dosing system using silicon-based micropump/valve and mass flow sensor
Publisher: Elsevier BV
Date: 06-1998
Liquid marble coalescence via vertical collision
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8SM00121A
Abstract: We determined the critical condition for the coalescence of two identical liquid marbles through collision.
Reconstruction from 2-D wavelet transform modulus maxima using projection
Publisher: Institution of Engineering and Technology (IET)
Date: 2000
An On-Chip SiC MEMS Device with Integrated Heating, Sensing, and Microfluidic Cooling Systems
Publisher: Wiley
Date: 12-08-2018
Signal-Based Methods in Dielectrophoresis for Cell and Particle Separation
Publisher: MDPI AG
Date: 11-07-2022
DOI: 10.3390/BIOS12070510
Abstract: Separation and detection of cells and particles in a suspension are essential for various applications, including biomedical investigations and clinical diagnostics. Microfluidics realizes the miniaturization of analytical devices by controlling the motion of a small volume of fluids in microchannels and microchambers. Accordingly, microfluidic devices have been widely used in particle/cell manipulation processes. Different microfluidic methods for particle separation include dielectrophoretic, magnetic, optical, acoustic, hydrodynamic, and chemical techniques. Dielectrophoresis (DEP) is a method for manipulating polarizable particles’ trajectories in non-uniform electric fields using unique dielectric characteristics. It provides several advantages for dealing with neutral bioparticles owing to its sensitivity, selectivity, and noninvasive nature. This review provides a detailed study on the signal-based DEP methods that use the applied signal parameters, including frequency, litude, phase, and shape for cell article separation and manipulation. Rather than employing complex channels or time-consuming fabrication procedures, these methods realize sorting and detecting the cells articles by modifying the signal parameters while using a relatively simple device. In addition, these methods can significantly impact clinical diagnostics by making low-cost and rapid separation possible. We conclude the review by discussing the technical and biological challenges of DEP techniques and providing future perspectives in this field.
Ultra-thin LPCVD silicon carbide membrane: A promising platform for bio-cell culturing
Publisher: IEEE
Date: 2018
Colorimetric and electrochemical quantification of global DNA methylation using a methyl cytosine-specific antibody
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7AN00526A
Abstract: We report a simple colorimetric (naked-eye) and electrochemical method for the rapid, sensitive and specific quantification of global methylation levels using only 25 ng of input DNA.
Liquid marble – a high-yield micro-photobioreactor platform
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3RE00221G
Abstract: This paper demonstrates the use of a transparent liquid marble as a micro-photobioreactor for microalgal culture, with enhanced performance due to high light transmissivity and large surface area.
Optothermotronic effect as an ultrasensitive thermal sensing technology for solid-state electronics
Publisher: American Association for the Advancement of Science (AAAS)
Date: 29-05-2020
Abstract: Optothermotronics enable a giant temperature coefficient of resistance using optoelectronic modulation of electric potential.
On-demand deterministic release of particles and cells using stretchable microfluidics
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1NH00679G
Abstract: This paper reports a stretchable microfluidic cell trapper for the on-demand release of particles and cells in a deterministic manner. The size of particles to be trapped and released can be tuned by stretching the device.
A PCR-free electrochemical method for messenger RNA detection in cancer tissue samples
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.BIOS.2017.06.051
Abstract: Despite having reliable and excellent diagnostic performances, the currently available messenger RNA (mRNA) detection methods mostly use enzymatic lification steps of the target mRNA which is generally affected by the s le manipulations, lification bias and longer assay time. This paper reports an lification-free electrochemical approach for the sensitive and selective detection of mRNA using a screen-printed gold electrode (SPE-Au). The target mRNA is selectively isolated by magnetic separation and adsorbed directly onto an unmodified SPE-Au. The surface-attached mRNA is then measured by differential pulse voltammetry (DPV) in the presence of [Fe(CN)
Anti-flooding cathode catalyst layer for high performance PEM fuel cell
Publisher: Elsevier BV
Date: 04-2009
Manipulation of liquid marbles
Publisher: Springer Science and Business Media LLC
Date: 23-05-2015
Thermal and Mechanical Stabilities of Core-shell Microparticles Containing a Liquid Core
Publisher: Research Square Platform LLC
Date: 02-09-2021
DOI: 10.21203/RS.3.RS-870641/V1
Abstract: Thorough understanding of the behaviour of core-shell microparticles with a liquid core is essential for determining their performance in applications under different operation conditions. This paper reports the behaviour of core-shell particles with a liquid core under thermal and mechanical loads. First, we formulated an analytical model for the heating process of a core-shell microparticle with a liquid core. Next, we utilised an axisymmetric model of an elastic spherical shell upon compression to describe the deformation of a core-shell microparticle. Finally, we conducted experiments to validate these models. Both thermal and mechanical models agree well with the experimental data. The maximum temperature a core-shell microparticle can withstand depends on the liquid, the geometry, and the material of the shell. The critical compression force before rupture of a core-shell microparticle depends on the Poisson’s ratio of the shell material and the shell thickness relative to the outer shell radius. The rupture force and rupture temperature increase with increasing shell thickness.
Rapid Mixing Using Two-Phase Hydraulic Focusing in Microchannels
Publisher: Springer Science and Business Media LLC
Date: 03-2005
DOI: 10.1007/S10544-005-6167-7
Abstract: Rapid mixing is important in biomedical analysis. In this study, rapid mixing is obtained through two-phase hydraulic focusing in microchannels. Two mixing streams are focused by two sheath streams. Assuming a laminar flow in the channel, the spreading behavior of the two immiscible fluids is modeled and solved analytically. The results show that both viscosity ratio and flow rate ratio between the sheath flow and the s le flow can affect the focusing ratio. Thus, the mixing path of the s le flows can be adjusted by either viscosity ratio or flow rate ratio. Furthermore, an analytical model was proposed and solved for convective/diffusive mixing between the s le streams. According to this model, the focusing ratio is a key parameter for rapid mixing. A fully polymeric micro mixer was fabricated and tested for verification of the presented analytical models. The micromixer was fabricated by laser micromachining and adhesive bonding. The characterization results show the promising potential of mixing in microscale using two-phase hydraulic focusing.
Thermal and Mechanical Stabilities of Core-shell Microparticles Containing a Liquid Core
Publisher: Research Square Platform LLC
Date: 15-09-2021
DOI: 10.21203/RS.3.RS-870641/V2
Abstract: Thorough understanding of the behaviour of core-shell microparticles with a liquid core is essential for determining their performance in applications under different operation conditions. This paper reports the behaviour of core-shell particles with a liquid core under thermal and mechanical loads. First, we formulated an analytical model for the heating process of a core-shell microparticle with a liquid core. Next, we utilised an axisymmetric model of an elastic spherical shell upon compression to describe the deformation of a core-shell microparticle. Finally, we conducted experiments to validate these models. Both thermal and mechanical models agree well with the experimental data. The maximum temperature a core-shell microparticle can withstand depends on the liquid, the geometry, and the material of the shell. The critical compression force before rupture of a core-shell microparticle depends on the Poisson’s ratio of the shell material and the shell thickness relative to the outer shell radius. The rupture force and rupture temperature increase with increasing shell thickness.
Steady-state analytical model of suspended p-type 3C-SiC bridges under consideration of Joule heating
Publisher: IOP Publishing
Date: 05-06-2017
Modeling and experimental characterization of peak tailing in DNA gel electrophoresis
Publisher: Springer Science and Business Media LLC
Date: 21-11-2006
A simple method for evaluating and predicting chaotic advection in microfluidic slugs
Publisher: Elsevier BV
Date: 10-2010
Numerical modeling of tunable optofluidics lens based on combined effect of hydrodynamics and electroosmosis
Publisher: Elsevier BV
Date: 04-2012
Multi-functional, optofluidic, in-plane, bi-concave lens: tuning light beam from focused to divergent
Publisher: Springer Science and Business Media LLC
Date: 10-10-2010
Fabrication of a sensitive pressure sensor using carbon nanotube micro-yarns
Publisher: IEEE
Date: 10-2017
Redox-mediated dissolution of paramagnetic nanolids to achieve a smart theranostic system
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3NR05687B
Abstract: Redox sensitive dissolution of paramagnetic NPs (Mn 3 O 4 ) results in a controlled drug release and enhanced magnetic resonance imaging.
Particle-Based Numerical Modelling of Liquid Marbles: Recent Advances and Future Perspectives
Publisher: Springer Science and Business Media LLC
Date: 07-12-2021
Deformation of ferrofluid marbles in the presence of a permanent magnet
Publisher: American Chemical Society (ACS)
Date: 28-10-2013
DOI: 10.1021/LA4032859
Abstract: This paper investigates the deformation of ferrofluid marbles in the presence of a permanent magnet. Ferrofluid marbles are formed using a water-based ferrofluid and 1 μm hydrophobic polytetrafluoride particles. A marble placed on a Teflon coated glass plate deforms under gravity. In the presence of a permanent magnet, the marble is further deformed with a larger contact area. The geometric parameters are normalized by the radius of an undistorted spherical marble. The paper first discusses a scaling relationship between the dimensionless radius of the contact area as well as the dimensionless height and the magnetic Bond number. The dimensionless contact radius is proportional to the fourth root of the magnetic bond number. The dimensionless height scales with the inverse square root of the magnetic Bond number. In the case of a moving marble dragged by a permanent magnet, the deformation is evaluated as the difference between advancing and receding curvatures of the top view. The dimensionless height and the contact diameter of the marble do not significantly depend on the speed or the capillary number. The scaling analysis and experimental data show that the deformation is proportional to the capillary number.
RNA Biomarkers: Diagnostic and Prognostic Potentials and Recent Developments of Electrochemical Biosensors
Publisher: Wiley
Date: 05-06-2017
Controllable high-performance liquid marble micromixer
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2LC00017B
Abstract: A high-performance micromixer based on rolling liquid marble.
Measurement of buried undercut structures in microfluidic devices by laser fluorescent confocal microscopy
Publisher: Optica Publishing Group
Date: 11-11-2009
DOI: 10.1364/AO.48.006432
Utilizing large hall offset voltage for conversion free 4H-SiC strain sensor
Publisher: IEEE
Date: 2018
Magnetophoresis of diamagnetic microparticles in a weak magnetic field
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4LC00885E
Abstract: We investigated the phenomenon of magnetophoresis of diamagnetic microparticles suspended in a ferrofluid in a weak uniform magnetic field. No high field gradient is required for particle migration.
Core-Shell Beads Made by Composite Liquid Marble Technology as A Versatile Microreactor for Polymerase Chain Reaction
Publisher: MDPI AG
Date: 26-02-2020
DOI: 10.3390/MI11030242
Abstract: Over the last three decades, the protocols and procedures of the DNA lification technique, polymerase chain reaction (PCR), have been optimized and well developed. However, there have been no significant innovations in processes for s le dispersion for PCR that have reduced the amount of single-use or unrecyclable plastic waste produced. To address the issue of plastic waste, this paper reports the synthesis and successful use of a core-shell bead microreactor using photopolymerization of a composite liquid marble as a dispersion process. This platform uses the core-shell bead as a simple and effective s le dispersion medium that significantly reduces plastic waste generated compared to conventional PCR processes. Other improvements over conventional PCR processes of the novel dispersion platform include increasing the throughput capability, enhancing the performance and portability of the thermal cycler, and allowing for the contamination-free storage of s les after thermal cycling.
An Electromagnetically Actuated Double-Sided Cell-Stretching Device for Mechanobiology Research
Publisher: MDPI AG
Date: 22-08-2017
DOI: 10.3390/MI8080256
Recent microfluidic advances in submicron to nanoparticle manipulation and separation
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2LC00793B
Abstract: This paper comprehensively studies the latest progress in microfluidic technology for submicron and nanoparticle manipulation by elaborating on the physics, device design, working mechanism and applications of microfluidic technologies.
On-Chip Microparticle and Cell Washing Using Coflow of Viscoelastic Fluid and Newtonian Fluid
Publisher: American Chemical Society (ACS)
Date: 17-08-2017
DOI: 10.1021/ACS.ANALCHEM.7B02671
Abstract: This work investigates the on-chip washing process of microparticles and cells using coflow configuration of viscoelastic fluid and Newtonian fluid in a straight microchannel. By adding a small amount of biocompatible polymers into the particle medium or cell culture medium, the induced viscoelasticity can push particles and cells laterally from their original medium to the coflow Newtonian medium. This behavior can be used for particle or cell washing. First, we demonstrated on-chip particle washing by the size-dependent migration speed using coflow of viscoelastic fluid and Newtonian fluid. The critical particle size for efficient particle washing was determined. Second, we demonstrated continuous on-chip washing of Jurkat cells using coflow of viscoelastic fluid and Newtonian fluid. The lateral migration process of Jurkat cells along the channel length was investigated. In addition, the cell washing quality was verified by hemocytometry and flow cytometry with a recovery rate as high as 92.8%. Scanning spectrophotometric measurements of the media from the two inlets and the two outlets demonstrated that diffusion of the coflow was negligible, indicating efficient cell washing from culture medium to phosphate-buffered saline medium. This technique may be a safer, simpler, cheaper, and more efficient alternative to the tedious conventional centrifugation methods and may open up a wide range of biomedical applications.
Mesoporous Iron Oxide Synthesized Using Poly(styrene-b-acrylic acid-b-ethylene glycol) Block Copolymer Micelles as Templates for Colorimetric and Electrochemical Detection of Glucose
Publisher: American Chemical Society (ACS)
Date: 19-12-2017
Abstract: Herein, we report the soft-templated preparation of mesoporous iron oxide using an asymmetric poly(styrene-b-acrylic acid-b-ethylene glycol) (PS-b-PAA-b-PEG) triblock copolymer. This polymer forms a micelle consisting of a PS core, a PAA shell, and a PEG corona in aqueous solutions, which can serve as a soft template. The mesoporous iron oxide obtained at an optimized calcination temperature of 400 °C exhibited an average pore diameter of 39 nm, with large specific surface area and pore volume of 86.9 m
Growth mechanism for alternating supply epitaxy: the unique pathway to achieve uniform silicon carbide films on multiple large-diameter silicon substrates
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5RA24797G
Abstract: The unique growth mechanism of alternating supply epitaxy enables uniform 3C-SiC to be deposited on multiple large-diameter Si wafers.
Laser beam propagation in a flow aligned nematic liquid crystal: analysis on liquid/light interactions
Publisher: SPIE-Intl Soc Optical Eng
Date: 05-2011
DOI: 10.1117/1.3574767
Cell stretching devices as research tools: Engineering and biological considerations
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6LC00607H
Abstract: We review the different platforms for growing cells under the mechanical stimulus of stretching.
High throughput extraction of plasma using a secondary flow-aided inertial microfluidic device
Publisher: Royal Society of Chemistry (RSC)
Date: 18-07-2014
DOI: 10.1039/C4RA06513A
Micromachined flow sensors - a review
Publisher: Elsevier BV
Date: 03-1997
Autoantibodies as diagnostic and prognostic cancer biomarker: Detection techniques and approaches
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.BIOS.2019.111315
Abstract: Autoantibodies produced by the patients' own immune systems in response to foreign substances are emerging as an attractive biomarker for early detection of cancer. These serum immunobiomarkers are produced in large quantities despite the presence of very less amount of the corresponding antigens, and thus presenting themselves as a novel class of stable and minimally invasive disease biomarkers especially for cancer diagnosis. Although a plethora of research, including conventional molecular biology-based as well as cutting-edge optical and electrochemical strategies (biosensor), have been conducted to detect autoantibodies, most of these strategies are yet to be readily applicable in the off-laboratory settings at clinics. Herein, we detail the biogenesis, diagnostic, prognostic and therapeutic potential of autoantibodies as cancer biomarkers. With the particular emphasis on cutting-edge advances in electrochemistry, optical (surface plasmon resonance) and microfluidics techniques, this review entrusts the unmet needs and challenges of autoantibody detection approaches and provides a future perspective of the presented strategies. We believe this review can potentially guide the researchers towards the development of robust, reliable and sensitive detection strategies for tumor-associated autoantibodies and translation of these biomarkers to real clinical settings for diagnosis and prognosis of cancer.
High Throughput Cell-Free Extraction of Plasma by an Integrated Microfluidic Device Combining Inertial Focusing and Membrane
Publisher: ASME International
Date: 23-02-2017
DOI: 10.1115/1.4035588
Abstract: Plasma is a host of numerous analytes such as proteins, metabolites, circulating nucleic acids (CNAs), and pathogens, and it contains massive information about the functioning of the whole body, which is of great importance for the clinical diagnosis. Plasma needs to be completely cell-free for effective detection of these analytes. The key process of plasma extraction is to eliminate the contamination from blood cells. Centrifugation, a golden standard method for blood separation, is generally lab-intensive, time consuming, and even dangerous to some extent, and needs to be operated by well-trained staffs. Membrane filtration can filter cells very effectively according to its pore size, but it is prone to clogging by dense particle concentration and suffers from limited capacity of filtration. Frequent rinse is lab-intensive and undesirable. In this work, we proposed and fabricated an integrated microfluidic device that combined particle inertial focusing and membrane filter for high efficient blood plasma separation. The integrated microfluidic device was evaluated by the diluted (×1/10, ×1/20) whole blood, and the quality of the extracted blood plasma was measured and compared with that from the standard centrifugation. We found that the quality of the extracted blood plasma from the proposed device can be equivalent to that from the standard centrifugation. This study demonstrates a significant progress toward the practical application of inertial microfluidics with membrane filter for high-throughput and highly efficient blood plasma extraction.
Optoelectronic Enhancement for Piezoresistive Pressure Sensor
Publisher: IEEE
Date: 2020
Electrical Resistance of Carbon Nanotube Yarns under Compressive Transverse Pressure
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2018
Influence of Interfacial Gas Enrichment on Controlled Coalescence of Oil Droplets in Water in Microfluidics
Publisher: American Chemical Society (ACS)
Date: 12-02-2019
DOI: 10.1021/ACS.LANGMUIR.8B03486
Abstract: Interfacial gas enrichment (IGE) of dissolved gases in water is shown to govern the strong attraction between solid hydrophobic surfaces of an atomic force microscopy (AFM) colloidal probe and solid substrate. However, the role of IGE in controlling the attraction between fluid-fluid interfaces of foam films and emulsion films is difficult to establish by AFM techniques because of the extremely fast coalescence. Here, we applied droplet-based microfluidics to capture the fast coalescence event under the creeping flow condition and quantify the effect of IGE on the drainage and stability of water films between coalescing oil droplets. The amount of dissolved gases is controlled by partially degassing the oil phase. When the amount of dissolved gases (oxygen) in oil decreases (from 7.89 to 4.59 mg/L), the average drainage time of coalescence significantly increases (from 19 to 50 ms). Our theoretical quantification of the coalescence by incorporating IGE into the multilayer van der Waals attraction theory confirms the acceleration of film drainage dynamics by the van der Waals attractive force generated by IGE. The thickness of the IGE layer decreases from 5.5 to 4.9 nm when the amount of dissolved gas decreases from 7.89 to 4.59 mg/L. All these results establish the universal role of dissolved gases in governing the strong attraction between particulate hydrophobic interfaces.
Giant piezoresistive effect by optoelectronic coupling in a heterojunction
Publisher: Springer Science and Business Media LLC
Date: 12-09-2019
DOI: 10.1038/S41467-019-11965-5
Abstract: Enhancing the piezoresistive effect is crucial for improving the sensitivity of mechanical sensors. Herein, we report that the piezoresistive effect in a semiconductor heterojunction can be enormously enhanced via optoelectronic coupling. A lateral photovoltage, which is generated in the top material layer of a heterojunction under non-uniform illumination, can be coupled with an optimally tuned electric current to modulate the magnitude of the piezoresistive effect. We demonstrate a tuneable giant piezoresistive effect in a cubic silicon carbide/silicon heterojunction, resulting in an extraordinarily high gauge factor of approximately 58,000, which is the highest gauge factor reported for semiconductor-based mechanical sensors to date. This gauge factor is approximately 30,000 times greater than that of commercial metal strain gauges and more than 2,000 times greater than that of cubic silicon carbide. The phenomenon discovered can pave the way for the development of ultra-sensitive sensor technology.
Biodegradable Polymers for Micro Elastofluidics
Publisher: Wiley
Date: 09-06-2023
Abstract: Micro elastofluidics is an emerging research field that encompasses characteristics of conventional microfluidics and fluid‐structure interactions. Micro elastofluidics is expected to enable practical applications, for instance, where direct contact between biological s les and fluid handling systems is required. Besides design optimization, choosing a proper material is critical to the practical use of micro elastofluidics upon interaction with biological interface and after its functional lifetime. Biodegradable polymers are one of the most studied materials for this purpose. Micro elastofluidic devices made of biodegradable polymers possess exceptional mechanical elasticity, excellent bio compatibility, and structural degradability into non‐toxic products. This article provides an insightful and systematic review of the utilization of biodegradable polymers in digital and continuous‐flow micro elastofluidics.
Mass transport improvement in microscale using diluted ferrofluid and a non-uniform magnetic field
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA11703A
Abstract: We investigate the mass transport enhancement of a non-magnetic fluorescent dye with the help of diluted ferrofluid and a non-uniform magnetic field.
Missing value imputation for gene expression data: computational techniques to recover missing data from available information
Publisher: Oxford University Press (OUP)
Date: 14-12-2010
DOI: 10.1093/BIB/BBQ080
Abstract: Microarray gene expression data generally suffers from missing value problem due to a variety of experimental reasons. Since the missing data points can adversely affect downstream analysis, many algorithms have been proposed to impute missing values. In this survey, we provide a comprehensive review of existing missing value imputation algorithms, focusing on their underlying algorithmic techniques and how they utilize local or global information from within the data, or their use of domain knowledge during imputation. In addition, we describe how the imputation results can be validated and the different ways to assess the performance of different imputation algorithms, as well as a discussion on some possible future research directions. It is hoped that this review will give the readers a good understanding of the current development in this field and inspire them to come up with the next generation of imputation algorithms.
Electrohydrodynamic and shear-stress interfacial instability of two streaming viscous liquid inside a microchannel for tangential electric fields
Publisher: Bentham Science Publishers Ltd.
Date: 02-2012
Magnetophoretic separation of diamagnetic particles through parallel ferrofluid streams
Publisher: Elsevier BV
Date: 12-2018
A Stretchable Kirigami‐Inspired Self‐Powered Electroactive Sensor for Tensile Strain and Torsion Sensing
Publisher: Wiley
Date: 16-11-2021
Abstract: Electroactive polymer has a great potential to be employed for making a self‐powered sensor due to the ionic movement of the mobile cation that exists in the polymer structure itself. However, applying an electroactive‐based sensor as wearable gadget can be challenging due to its limited detection range and nonconformity. Inspired by the Kirigami structure, herein, it has been demonstrated that a self‐powered electroactive‐based sensor with improved conformality. It has been found that the Kirigami structure can enhance the sensor sensitivity significantly. The sensor exhibited high sensitivity to a uniaxial strain deformation with more than 300% sensitivity and a broad sensing range of up to 80% strain. In addition to being able to detect the uniaxial strain, the Kirigami‐patterned sensor also has good torsion and mixed torsion–strain dependent properties, making it a good multifunctional sensor. As a proof‐of‐concept demonstration for applications in monitoring human activities, it has been successfully demonstrated that the proposed Kirigami‐patterned sensor is able to monitor wrist movements and respiration rate. Notably, this Kirigami‐patterned electroactive‐based sensor has significantly broadened the application of electroactive polymer on advanced wearable electronics.
Self-triggering regime for synchronized formation of two droplets
Publisher: AIP Publishing
Date: 24-02-2014
DOI: 10.1063/1.4866970
Abstract: This letter reports experimental results of the synchronized formation of two liquid droplets in a microfluidic device. A pair of droplets is formed periodically in a T-junction configuration with a single channel for the continuous phase and two inlets for the dispersed phase. The pair-wise droplet formation process is self-triggering, as the first droplet formed upstream triggers the breakup of the second droplet downstream. The triggered breakup happens across the different formation regimes. The effects of capillary number and flow rate ratio on the size and order of the droplets are investigated. The configuration reported here may serve as a parallel to serial s ling device for droplet-based lab-on-a-chip platforms.
Eccentricity effects of microhole arrays on drag reduction efficiency of microchannels with a hydrophobic wall
Publisher: AIP Publishing
Date: 11-2012
DOI: 10.1063/1.4767539
Abstract: This paper experimentally investigates the effects of microhole eccentricity on the slip lengths of Stokes flow in microchannels with the bottom wall made of microhole arrays. The wettability of such microhole structures fabricated by the replica molding of polydimethylsiloxane is first analyzed measuring both static and dynamic contact angles. Subsequently, the drag reduction performance of the microchannels with such hydrophobic microhole surfaces is evaluated. The results indicate that the impact of microhole eccentricity on drag reduction performance correlates well with the contact angle hysteresis rather than with the static contact angle. Furthermore, microhole arrays with large normalized width and zero eccentricity show the minimum contact angle hysteresis of 18.7°. In these microchannels, the maximum percentage increase in the relative velocity is 39% corresponding to a slip length of 2.49 μm. For the same normalized width, increasing the normalized eccentricity to 2.6 increases the contact angle hysteresis to 36.5° that eventually reduces the percentage increase in relative velocity and slip length down to 16% and 0.91 μm, respectively. The obtained results are in qualitative agreement with the existing theoretical and numerical models. These findings provide additional insights in the design and fabrication of efficient micropatterned channels for reducing the flow resistance, and leave open questions for theoreticians to further investigate in this field.
A novel numerical model to predict the morphological behavior of magnetic liquid marbles using coarse grained molecular dynamics concepts
Publisher: AIP Publishing
Date: 2018
DOI: 10.1063/1.5000289
Abstract: Liquid marbles are liquid droplets coated with superhydrophobic powders whose morphology is governed by the gravitational and surface tension forces. Small liquid marbles take spherical shapes, while larger liquid marbles exhibit puddle shapes due to the dominance of gravitational forces. Liquid marbles coated with hydrophobic magnetic powders respond to an external magnetic field. This unique feature of magnetic liquid marbles is very attractive for digital microfluidics and drug delivery systems. Several experimental studies have reported the behavior of the liquid marbles. However, the complete behavior of liquid marbles under various environmental conditions is yet to be understood. Modeling techniques can be used to predict the properties and the behavior of the liquid marbles effectively and efficiently. A robust liquid marble model will inspire new experiments and provide new insights. This paper presents a novel numerical modeling technique to predict the morphology of magnetic liquid marbles based on coarse grained molecular dynamics concepts. The proposed model is employed to predict the changes in height of a magnetic liquid marble against its width and compared with the experimental data. The model predictions agree well with the experimental findings. Subsequently, the relationship between the morphology of a liquid marble with the properties of the liquid is investigated. Furthermore, the developed model is capable of simulating the reversible process of opening and closing of the magnetic liquid marble under the action of a magnetic force. The scaling analysis shows that the model predictions are consistent with the scaling laws. Finally, the proposed model is used to assess the compressibility of the liquid marbles. The proposed modeling approach has the potential to be a powerful tool to predict the behavior of magnetic liquid marbles serving as bioreactors.
Recent advances and current challenges in magnetophoresis based micro magnetofluidics
Publisher: AIP Publishing
Date: 05-2018
DOI: 10.1063/1.5035388
Abstract: The combination of magnetism and microscale fluid flow has opened up a new era for handling and manipulation of s les in microfluidics. In particular, magnetophoresis, the migration of particles in a magnetic field, is extremely attractive for microfluidic handling due to its contactless nature, independence of ionic concentration, and lack of induced heating. The present paper focuses on recent advances and current challenges of magnetophoresis and highlights the key parameters affecting the manipulation of particles by magnetophoresis. The magnetic field is discussed according to their relative motion to the s le as stationary and dynamic fields. The migration of particles is categorized as positive and negative magnetophoresis. The applications of magnetophoresis are discussed according to the basic manipulation tasks such as mixing, separation, and trapping of particles or cells. Finally, the paper highlights the limitations of current approaches and provides the future perspective for this research area.
Distribution and trajectories of floating and benthic marine macrolitter in the south-eastern North Sea
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.MARPOLBUL.2018.05.003
Abstract: In coastal waters the identification of sources, trajectories and deposition sites of marine litter is often h ered by the complex oceanography of shallow shelf seas. We conducted a multi-annual survey on litter at the sea surface and on the seafloor in the south-eastern North Sea. Bottom trawling was identified as a major source of marine litter. Oceanographic modelling revealed that the distribution of floating litter in the North Sea is largely determined by the site of origin of floating objects whereas the trajectories are strongly influenced by wind drag. Methods adopted from species distribution modelling indicated that resuspension of benthic litter and near-bottom transport processes strongly influence the distribution of litter on the seafloor. Major sink regions for floating marine litter were identified at the west coast of Denmark and in the Skagerrak. Our results may support the development of strategies to reduce the pollution of the North Sea.
A fast and low memory image coding algorithm based on lifting wavelet transform and modified SPIHT
Publisher: Elsevier BV
Date: 03-2008
Kinematics and deformation of ferrofluid droplets under magnetic actuation
Publisher: Springer Science and Business Media LLC
Date: 30-01-2007
Passive micromixer for luminol-peroxide chemiluminescence detection
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1AN15280G
Abstract: This paper reports a microchip with an integrated passive micromixer based on chaotic advection. The micromixer with staggered herringbone structures was used for luminol-peroxide chemiluminescence detection. The micromixer was examined to assess its suitability for chemiluminescence reaction. The relationship between the flow rate and the location of maximum chemiluminescence intensity was investigated. The light intensity was detected using an optical fiber attached along the mixing channel and a photon detector. A linear correlation between chemiluminescence intensity and the concentration of cobalt(ii) ions or hydrogen peroxide was observed. This microchip has a potential application in environmental monitoring for industries involved in heavy metals and in medical diagnostics.
Self-Aligned Interdigitated Transducers for Acoustofluidics
Publisher: MDPI AG
Date: 25-11-2016
DOI: 10.3390/MI7120216
Fabrication of micropumps with Q-switched Nd : YAG-Lasers
Publisher: SPIE
Date: 19-02-2002
DOI: 10.1117/12.456871
Sample loading and retrieval by centrifugation in a closed-loop PCR microchip
Publisher: Springer Science and Business Media LLC
Date: 30-11-2012
Ultrasensitive Self-Powered Position-Sensitive Detector Based on n-3C-SiC/p-Si Heterojunctions
Publisher: American Chemical Society (ACS)
Date: 09-02-2022
Enhanced Electrohydrodynamics for Electrospinning a Highly Sensitive Flexible Fiber-Based Piezoelectric Sensor
Publisher: American Chemical Society (ACS)
Date: 07-03-2022
A novel viscoelastic-based ferrofluid for continuous sheathless microfluidic separation of nonmagnetic microparticles
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6LC01007E
Abstract: We proposed and developed a novel viscoelastic ferrofluid, and demonstrated its superior advantages for continuous sheathless separation of nonmagnetic particles.
Pressure-driven filling of liquid metal in closed-end microchannels
Publisher: American Physical Society (APS)
Date: 07-09-2018
Liquid marble-based digital microfluidics – fundamentals and applications
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0LC01290D
Abstract: Liquid marbles are microliter-sized non-wetting droplets. Their versatility makes them an attractive digital microfluidics platform. This paper provides state-of-the-art discoveries in the physics of liquid marbles and their applications.
Detection of FGFR2 : FAM76A Fusion Gene in Circulating Tumor RNA Based on Catalytic Signal Amplification of Graphene Oxide-loaded Magnetic Nanoparticles
Publisher: Wiley
Date: 04-07-2018
Convective–diffusive transport in parallel lamination micromixers
Publisher: Springer Science and Business Media LLC
Date: 10-11-2004
Paper-Based Electronics Using Graphite and Silver Nanoparticles for Respiration Monitoring
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-12-2019
Digital microfluidics with a magnetically actuated floating liquid marble
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6LC00378H
Abstract: We report a digital microfluidics platform based on floating liquid marbles.
Modelling, fabrication and characterization of a polymeric micromixer based on sequential segmentation
Publisher: Springer Science and Business Media LLC
Date: 06-2006
DOI: 10.1007/S10544-006-7708-4
Abstract: Effective and fast mixing is important for many microfluidic applications. In many cases, mixing is limited by molecular diffusion due to constrains of the laminar flow in the microscale regime. According to scaling law, decreasing the mixing path can shorten the mixing time and enhance mixing quality. One of the techniques for reducing mixing path is sequential segmentation. This technique ides solvent and solute into segments in axial direction. The so-called Taylor-Aris dispersion can improve axial transport by three orders of magnitudes. The mixing path can be controlled by the switching frequency and the mean velocity of the flow. Mixing ratio can be controlled by pulse width modulation of the switching signal. This paper first presents a simple time-dependent one-dimensional analytical model for sequential segmentation. The model considers an arbitrary mixing ratio between solute and solvent as well as the axial Taylor-Aris dispersion. Next, a micromixer was designed and fabricated based on polymeric micromachining. The micromixer was formed by laminating four polymer layers. The layers are micro machined by a CO(2) laser. Switching of the fluid flows was realized by two piezoelectric valves. Mixing experiments were evaluated optically. The concentration profile along the mixing channel agrees qualitatively well with the analytical model. Furthermore, mixing results at different switching frequencies were investigated. Due to the dynamic behavior of the valves and the fluidic system, mixing quality decreases with increasing switching frequency.
Environment-friendly carbon nanotube based flexible electronics for noninvasive and wearable healthcare
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6TC02708C
Abstract: Carbon nanotube yarns are employed to develop environment-friendly, low cost and lightweight paper-based flexible devices for wearable applications in temperature and respiratory monitoring, and personal healthcare.
Thermocapillary effect of a liquid plug in transient temperature fields (vol 44, pg 1139, 2005)
Publisher: IOP Publishing
Date: 07-2006
DOI: 10.1143/JJAP.45.6058
Measuring the effective surface tension of a floating liquid marble using X-ray imaging
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1SM00101A
Abstract: Liquid marbles are non-wetting droplets coated with microscopic powder. We measure the effective surface tension of a liquid marble using X-ray which reveals the hidden liquid–solid interface. A systematic curve fitting procedure is also provided.
Modelling of an uniaxial single-sided magnetically actuated cell-stretching device
Publisher: Elsevier BV
Date: 12-2016
Is geriatric assessment being incorporated into general oncology?
Publisher: Elsevier BV
Date: 04-2014
RhoA and Rac1 in Liver Cancer Cells: Induction of Overexpression Using Mechanical Stimulation
Publisher: MDPI AG
Date: 28-07-2020
DOI: 10.3390/MI11080729
Abstract: Liver cancer, especially hepatocellular carcinoma (HCC), is an aggressive disease with an extremely high mortality rate. Unfortunately, no promising markers are currently available for the early diagnosis of this disease. Thus, a reliable biomarker reflecting the early behaviour of the tumour will be valuable for diagnosis and treatment. The Ras homologous (Rho) GTPases, which belong to the small guanosine triphosphate (GTP) binding proteins, have been reported to play an important role in mediating liver cancer based on their important function in cytoskeletal reorganisation. These proteins can be either oncogenic or tumour suppressors. They are also associated with the acquirement of malignant features by cancer cells. The overexpression of RhoA and Rac1, members of the Rho GTPases, have been linked with carcinogenesis and the progression of different types of cancer. In the quest of elucidating the role of mechanical stimulation in the mechanobiology of liver cancer cells, this paper evaluates the effect of stretching on the expression levels of RhoA and Rac1 in different types of liver cancers. It is shown that that stretching liver cancer cells significantly increases the expression levels of RhoA and Rac1 in HCC and cholangiocarcinoma cell lines. We hypothesise that this relatively simple and sensitive method could be helpful for screening biological features and provide suitable treatment guidance for liver cancer patients.
Acoustic streaming in micromachined flexural plate wave devices: numerical simulation and experimental verification
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2000
DOI: 10.1109/58.883536
Abstract: This paper presents the numerical simulation and experimental validation of acoustic streaming in micromachined flexural plate wave (FPW) devices. Two-dimensional and three-dimensional models of two device types were considered: the classical device with parallel interdigitated electrodes and the focused device with curved electrodes. Influences of different parameters on the time-averaged velocity were investigated. Thermal transport effects of the acoustic streaming were also considered. We observed the lifying effect of the streaming in the second type numerically and experimentally. To verify simulation results, the method of the particle image velocimetry (PIV) was applied in the experimental investigation.
Development of 3-component force-moment balance for low speed water tunnel
Publisher: World Scientific Pub Co Pte Lt
Date: 20-12-2005
DOI: 10.1142/S0217984905009948
Abstract: An effort is made to develop a new 3-component force-moment balance, which is capable of measuring lift force, drag force and pitching moment of a model mounted in the water tunnel. The concept used in the balance design is the bending- beam principle. The forces acting on the spring element cause strains on its surface, which are measured by strain gauges. Since strain yielded by the axial force is usually very small, therefore it is not practical to measure axial force using strain gauge directly to sense the strain in axial direction. The main idea of the new balance design is to translate all desired forces (lift and drag) in such a way that they yield bending strain at selected strain-gauge station. This is done by using a bending balance geometry. Under this apparatus, the model wing is mounted at one of its end to the bending balance. The corresponding Lift, Drag forces and Pitching moment are translated into moments at the other end of the balance, and can be measured from sets of strain gauges in bending mode (twisting mode for pitching moment). Ex le readings are presented in this paper.
Lab-on-a-Chip Technologies for Microgravity Simulation and Space Applications
Publisher: MDPI AG
Date: 31-12-2022
DOI: 10.3390/MI14010116
Abstract: Gravity plays an important role in the development of life on earth. The effect of gravity on living organisms can be investigated by controlling the magnitude of gravity. Most reduced gravity experiments are conducted on the Lower Earth Orbit (LEO) in the International Space Station (ISS). However, running experiments in ISS face challenges such as high cost, extreme condition, lack of direct accessibility, and long waiting period. Therefore, researchers have developed various ground-based devices and methods to perform reduced gravity experiments. However, the advantage of space conditions for developing new drugs, vaccines, and chemical applications requires more attention and new research. Advancements in conventional methods and the development of new methods are necessary to fulfil these demands. The advantages of Lab-on-a-Chip (LOC) devices make them an attractive option for simulating microgravity. This paper briefly reviews the advancement of LOC technologies for simulating microgravity in an earth-based laboratory.
Microfluidic platform for controlling the differentiation of embryoid bodies
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B903753E
LOW-COST SILICON SENSORS FOR MASS-FLOW MEASUREMENT OF LIQUIDS AND GASES
Publisher: Elsevier BV
Date: 06-1995
Porous nanozymes: the peroxidase-mimetic activity of mesoporous iron oxide for the colorimetric and electrochemical detection of global DNA methylation
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8TB01132J
Abstract: Peroxidase-mimetic activity of mesoporous Fe 2 O 3 nanomaterials in global DNA methylation detection using naked eye and electrochemical readout.
Wide bandgap semiconductor nanomembranes as a long-term biointerface for flexible, implanted neuromodulator
Publisher: Proceedings of the National Academy of Sciences
Date: 08-08-2022
Abstract: Electrical neuron stimulation holds promise for treating chronic neurological disorders, including spinal cord injury, epilepsy, and Parkinson’s disease. The implementation of ultrathin, flexible electrodes that can offer noninvasive attachment to soft neural tissues is a breakthrough for timely, continuous, programable, and spatial stimulations. With strict flexibility requirements in neural implanted stimulations, the use of conventional thick and bulky packages is no longer applicable, posing major technical issues such as short device lifetime and long-term stability. We introduce herein a concept of long-lived flexible neural electrodes using silicon carbide (SiC) nanomembranes as a faradic interface and thermal oxide thin films as an electrical barrier layer. The SiC nanomembranes were developed using a chemical vapor deposition (CVD) process at the wafer level, and thermal oxide was grown using a high-quality wet oxidation technique. The proposed material developments are highly scalable and compatible with MEMS technologies, facilitating the mass production of long-lived implanted bioelectrodes. Our experimental results showed excellent stability of the SiC/silicon dioxide (SiO 2 ) bioelectronic system that can potentially last for several decades with well-maintained electronic properties in biofluid environments. We demonstrated the capability of the proposed material system for peripheral nerve stimulation in an animal model, showing muscle contraction responses comparable to those of a standard non-implanted nerve stimulation device. The design concept, scalable fabrication approach, and multimodal functionalities of SiC/SiO 2 flexible electronics offer an exciting possibility for fundamental neuroscience studies, as well as for neural stimulation–based therapies.
A circular ferrofluid driven microchip for rapid polymerase chain reaction
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B700575J
Abstract: In the past few years, much attention has been paid to the development of miniaturized polymerase chain reaction (PCR) devices. After a continuous flow (CF) PCR chip was introduced, several CFPCR systems employing various pumping mechanisms were reported. However, the use of pumps increases cost and imposes a high requirement on microchip bonding integrity due to the application of high pressure. Other significant limitations of CFPCR devices include the large footprint of the microchip and the fixed cycle number which is dictated by the channel layout. In this paper, we present a novel circular close-loop ferrofluid driven microchip for rapid PCR. A small ferrofluid plug, containing sub-domain magnetic particles in a liquid carrier, is driven by an external magnet along the circular microchannel, which in turn propels the PCR mixture through three temperature zones. Amplification of a 500 bp lambda DNA fragment has been demonstrated on the polymethyl methacrylate (PMMA) PCR microchip fabricated by CO(2) laser ablation and bonded by a low pressure, high temperature technique. Successful PCR was achieved in less than 4 min. Effects of cycle number and cycle time on PCR products were investigated. Using a magnet as the actuator eliminates the need for expensive pumps and provides advantages of low cost, small power consumption, low requirement on bonding strength and flexible number of PCR cycles. Furthermore, the microchip has a much simpler design and smaller footprint compared to the rectangular serpentine CFPCR devices. To demonstrate its application in forensics, a 16-loci short tandem repeat (STR) s le was successfully lified using the PCR microchip.
High-Throughput Separation of White Blood Cells From Whole Blood Using Inertial Microfluidics
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2017
A new structure of Tesla coupled nozzle in synthetic jet micro-pump
Publisher: Elsevier BV
Date: 11-2020
Low-frequency acoustic atomization with oscillatory flow around micropillars in a microfluidic device
Publisher: AIP Publishing
Date: 06-10-2014
DOI: 10.1063/1.4897343
Abstract: This letter reports a low frequency acoustic atomization technique with oscillatory extensional flow around micropillars. Large droplets passing through two micropillars are elongated. Small droplets are then produced through the pinch-off process at the spindle-shape ends. As the actuation frequency increases, the droplet size decreases with increasing monodispersity. This method is suitable for in-situ mass production of fine droplets in a multi-phase environment without external pumping. Small particles encapsulation was demonstrated with the current technique.
CHAPTER 3: Technological Development-Droplet as a Tool
Publisher: The Royal Society of Chemistry
Date: 27-11-2021
DOI: 10.1039/9781839162855-00045
Abstract: The high uptake of droplet microfluidics in multidisciplinary research is mainly due to its capability of being a micro-scale laboratory with high versatility in controlling each microreactor. Through the implementation of three main manipulation methods, multiple reactions can be produced and subsequently used for different applications. Droplets of a predetermined medium are first generated. Subsequently, the coalescence of different droplets can also take place to mix different reagents. Finally, sorting of droplets according to pre-set variables is carried out, facilitating the analysis of results. Each manipulation method, however, can be carried out using a variety of active control methods. These can be categorized into electrical, magnetic, thermal, pneumatic, and occasionally acoustic and optical means. Further elaboration is provided in this chapter to illustrate these methods with the repertoire of mechanisms developed for these purposes. The advancement of such techniques enables high selectivity with minimal waste of resources, reducing the carbon footprint of laboratories while concurrently pursuing science.
A Portable Device for LAMP Based Detection of Sars-Cov-2
Publisher: MDPI AG
Date: 28-07-2021
DOI: 10.20944/PREPRINTS202107.0640.V1
Abstract: This paper reports the design, development, and testing of a novel, yet simple and low-cost portable device for the rapid detection of SARS-CoV-2. The device performs loop mediated isothermal lification (LAMP) and provides visually distinguishable images of the fluorescence emitted from the s les. The device utilises an aluminium block embedded with a cartridge heater for isothermal heating of the s le and a single-board computer and camera for fluorescence detection. The device demonstrates promising results within 20 minutes using clinically relevant starting concentrations of the synthetic template. Time-to-signal data for this device are considerably lower compared to standard qPCR machine (~10-20 minutes vs & minutes) for 1& times starting template copy number. The device in its fully optimized and characterized state can potentially be used as simple to operate, rapid, sensitive, and inexpensive platform for population screening as well as point-of-need SARS-CoV-2 detection and patient management.
Floating mechanism of a small liquid marble
Publisher: Springer Science and Business Media LLC
Date: 23-02-2016
DOI: 10.1038/SREP21777
Abstract: Flotation of small solid objects and liquid droplets on water is critical to natural and industrial activities. This paper reports the floating mechanism of liquid marbles, or liquid droplets coated with hydrophobic microparticles. We used X-ray computed tomography (XCT) to acquire cross-sectional images of the floating liquid marble and interface between the different phases. We then analysed the shape of the liquid marble and the angles at the three-phase contact line (TPCL). We found that the small floating liquid marbles follow the mechanism governing the flotation of solid objects in terms of surface tension forces. However, the contact angles formed and deformation of the liquid marble resemble that of a sessile liquid droplet on a thin, elastic solid. For small liquid marbles, the contact angle varies with volume due to the deformability of the interface.
Picomolar detection of carbohydrate-lectin interactions on piezoelectrically printed microcantilever array
Publisher: Elsevier BV
Date: 06-2022
Uniaxial Cyclic Cell Stretching Device for Accelerating Cellular Studies
Publisher: MDPI AG
Date: 31-07-2023
DOI: 10.3390/MI14081537
Abstract: Cellular response to mechanical stimuli is a crucial factor for maintaining cell homeostasis. The interaction between the extracellular matrix and mechanical stress plays a significant role in organizing the cytoskeleton and aligning cells. Tools that apply mechanical forces to cells and tissues, as well as those capable of measuring the mechanical properties of biological cells, have greatly contributed to our understanding of fundamental mechanobiology. These tools have been extensively employed to unveil the substantial influence of mechanical cues on the development and progression of various diseases. In this report, we present an economical and high-performance uniaxial cell stretching device. This paper reports the detailed operation concept of the device, experimental design, and characterization. The device was tested with MDA-MB-231 breast cancer cells. The experimental results agree well with previously documented morphological changes resulting from stretching forces on cancer cells. Remarkably, our new device demonstrates comparable cellular changes within 30 min compared with the previous 2 h stretching duration. This third-generation device significantly improved the stretching capabilities compared with its previous counterparts, resulting in a remarkable reduction in stretching time and a substantial increase in overall efficiency. Moreover, the device design incorporates an open-source software interface, facilitating convenient parameter adjustments such as strain, stretching speed, frequency, and duration. Its versatility enables seamless integration with various optical microscopes, thereby yielding novel insights into the realm of mechanobiology.
Stretchable respiration sensors: Advanced designs and multifunctional platforms for wearable physiological monitoring
Publisher: Elsevier BV
Date: 10-2020
Generation of three-dimensional multiple spheroid model of olfactory ensheathing cells using floating liquid marbles.
Publisher: Springer Science and Business Media LLC
Date: 14-10-2015
DOI: 10.1038/SREP15083
Abstract: We describe a novel protocol for three-dimensional culturing of olfactory ensheathing cells (OECs), which can be used to understand how OECs interact with other cells in three dimensions. Transplantation of OECs is being trialled for repair of the paralysed spinal cord, with promising but variable results and thus the therapy needs improving. To date, studies of OEC behaviour in a multicellular environment have been h ered by the lack of suitable three-dimensional cell culture models. Here, we exploit the floating liquid marble, a liquid droplet coated with hydrophobic powder and placed on a liquid bath. The presence of the liquid bath increases the humidity and minimises the effect of evaporation. Floating liquid marbles allow the OECs to freely associate and interact to produce OEC spheroids with uniform shapes and sizes. In contrast, a sessile liquid marble on a solid surface suffers from evaporation and the cells aggregate with irregular shapes. We used floating liquid marbles to co-culture OECs with Schwann cells and astrocytes which formed natural structures without the confines of gels or bounding layers. This protocol can be used to determine how OECs and other cell types associate and interact while forming complex cell structures.
Magnetofluidic concentration and separation of non-magnetic particles using two magnet arrays
Publisher: AIP Publishing
Date: 07-2016
DOI: 10.1063/1.4955421
Abstract: The present paper reports the use of diluted ferrofluid and two arrays of permanent magnets for the size-selective concentration of non-magnetic particles. The micro magnetofluidic device consists of a straight channels sandwiched between two arrays of permanent magnets. The permanent magnets create multiple capture zones with minimum magnetic field strength along the channel. The complex interaction between magnetic forces and hydrodynamic force allows the device to operate in different regimes suitable for concentration of non-magnetic particles with small difference in size. Our experimental results show that non-magnetic particles with diameters of 3.1 μm and 4.8 μm can be discriminated and separated with this method. The results from this study could be used as a guide for the design of size-sensitive separation devices for particle and cell based on negative magnetophoresis.
Gold-loaded nanoporous ferric oxide nanocubes for electrocatalytic detection of microRNA at attomolar level
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.BIOS.2017.09.027
Abstract: A crucial issue in microRNA (miRNA) detection is the lack of sensitive method capable of detecting the low levels of miRNA in RNA s les. Herein, we present a sensitive and specific method for the electrocatalytic detection of miR-107 using gold-loaded nanoporous superparamagnetic iron oxide nanocubes (Au-NPFe
Microfluidic Array Chip for Parallel Detection of Waterborne Bacteria
Publisher: MDPI AG
Date: 16-12-2019
DOI: 10.3390/MI10120883
Abstract: The polymerase chain reaction (PCR) is a robust technique used to make multiple copies of a segment of DNA. However, the available PCR platforms require elaborate and time-consuming operations or costly instruments, hindering their application. Herein, we introduce a sandwiched glass–polydimethylsiloxane (PDMS)–glass microchip containing an array of reactors for the real-time PCR-based detection of multiple waterborne bacteria. The PCR solution was loaded into the array of reactors in a single step utilising capillary filling, eliminating the need for pumps, valves, and liquid handling instruments. Issues of generating and trapping bubbles during the loading chip step were addressed by creating smooth internal reactor surfaces. Triton X-100 was used to enhance PCR compatibility in the chip by minimising the nonspecific adsorption of enzymes. A custom-made real-time PCR instrument was also fabricated to provide thermal cycling to the array chip. The microfluidic device was successfully demonstrated for microbial faecal source tracking (MST) in water.
Isotropic piezoresistance of p-type 4H-SiC in (0001) plane
Publisher: AIP Publishing
Date: 02-07-2018
DOI: 10.1063/1.5037545
Abstract: In this work, the isotropic piezoresistance in the (0001) plane of p-type 4H-SiC was discovered by means of the hole energy shift calculation and the coordinate transformation. These results were also confirmed by the measurement of the piezoresistance using a bending beam method. The fundamental longitudinal and transverse piezoresistive coefficients π11 and π12 were found to be 6.43 × 10−11 Pa−1 and −5.12 × 10−11 Pa−1, respectively. The isotropy of the piezoresistance in the basal plane of p-type 4H-SiC is attributed to the isotropic hole energy shift under uniaxial strain. This interesting phenomenon in p-type 4H-SiC is promising for the design and fabrication of mechanical sensors and strain-engineered electronics since high sensitivity and consistent performance can be achieved regardless of the crystallographic orientation.
Microfluidic encapsulation of DNAs in liquid beads for digital PCR application
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3AN00868A
Abstract: This paper reports a digital polymerase chain reaction platform with liquid beads, liquid droplets encapsulated in a hard shell.
Digital polymerase chain reaction technology-recent advances and future perspectives
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8LC00990B
Abstract: We critically evaluate the state of the art of the development of digital polymerase chain reaction systems.
Opto-acousto-fluidic microscopy for three-dimensional label-free detection of droplets and cells in microchannels
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8LC00106E
Abstract: We present here a novel opto-acousto-fluidic microscopy approach for three-dimensional label-free detection of droplets and cells in microfluidic networks.
High temperature silicon-carbide-based flexible electronics for monitoring hazardous environments
Publisher: Elsevier BV
Date: 07-2020
Advances in ultrasensitive piezoresistive sensors: from conventional to flexible and stretchable applications
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1MH00538C
Abstract: This paper comprehensively reviews methods and approaches to enhance the piezoresistive effect, ranging from the quantum physical effect and new materials to nanoscopic and macroscopic structures, and from conventional rigid to soft electronic applications.
Three dimensional features of convective heat transfer in droplet-based microchannel heat sinks
Publisher: Elsevier BV
Date: 07-2015
Rare cell isolation and analysis in microfluidics
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3LC90136J
A tool for designing tree-like concentration gradient generators for lab-on-a-chip applications
Publisher: Elsevier BV
Date: 02-2020
Recent Advances and Future Perspectives on Microfluidic Liquid Handling
Publisher: MDPI AG
Date: 12-06-2017
DOI: 10.3390/MI8060186
Tunable multi-functional optofluidic biconcave lens
Publisher: IEEE
Date: 02-2011
A fully polymeric micropump with piezoelectric actuator
Publisher: Elsevier BV
Date: 2004
The stress-strain relationship of liquid marbles under compression
Publisher: AIP Publishing
Date: 28-01-2019
DOI: 10.1063/1.5079438
Abstract: Liquid marbles can be characterized using elastic solid models consisting of a liquid surrounded by a soft solid membrane. The elastic properties of liquid marbles determine the amount of compression under a given external force. This is an important property as the elasticity of liquid marbles determines their morphology under a given stress. We show that the stress-strain relationship of liquid marbles can be described by σ*Bo=0.6[1/(1−εhro)2−1], where Bo is the Bond number, σ* is the normalised stress, and εhr0 is the strain measured with respect to the equivalent radius of the liquid marble. This stress-strain relationship could pave the way for the development of microfluidic devices with robust liquid marbles.
Inorganic Nanocrystals Functionalized Mesoporous Silica Nanoparticles: Fabrication and Enhanced Bio-applications
Publisher: Frontiers Media SA
Date: 13-12-2017
Hydrogels as artificial matrices for cell seeding in microfluidic devices
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0RA08566A
Abstract: Hydrogel-based artificial scaffolds and its incorporation with microfluidic devices play a vital role in shifting in vitro models from two-dimensional (2D) cell culture to in vivo like three-dimensional (3D) cell culture
Self-powered monolithic accelerometer using a photonic gate
Publisher: Elsevier BV
Date: 10-2020
Advances in haemostatic sponges: Characteristics and the underlying mechanisms for rapid haemostasis
Publisher: Elsevier BV
Date: 09-2023
Mixing in microchannels based on hydrodynamic focusing and time-interleaved segmentation: Modelling and experiment
Publisher: SPIE
Date: 28-12-2006
DOI: 10.1117/12.639034
A microfluidic sensor for dynamic surface tension measurement
Publisher: SPIE
Date: 28-12-2005
DOI: 10.1117/12.639035
Numerical investigation of upstream pressure fluctuation during growth and breakup of pendant drops
Publisher: Elsevier BV
Date: 11-2011
2020 Micromachines Yong Investigator Award: Announcement and Interview with the Winner
Publisher: MDPI AG
Date: 02-01-2021
DOI: 10.3390/MI12010048
Abstract: After an extensive voting period, we are proud to present the winner of the Micromachines Young Investigator Award to: [...]
Analytical model of mixed electroosmotic/pressure driven three immiscible fluids in a rectangular microchannel
Publisher: Elsevier BV
Date: 09-2009
Oxygen plasma treatment for reducing hydrophobicity of a sealed polydimethylsiloxane microchannel
Publisher: AIP Publishing
Date: 09-2010
DOI: 10.1063/1.3466882
Abstract: Rapid prototyping of polydimethylsiloxane (PDMS) is often used to build microfluidic devices. However, the inherent hydrophobic nature of the material limits the use of PDMS in many applications. While different methods have been developed to transform the hydrophobic PDMS surface to a hydrophilic surface, the actual implementation proved to be time consuming due to differences in equipment and the need for characterization. This paper reports a simple and easy protocol combining a second extended oxygen plasma treatments and proper storage to produce usable hydrophilic PDMS devices. The results show that at a plasma power of 70 W, an extended treatment of over 5 min would allow the PDMS surface to remain hydrophilic for more than 6 h. Storing the treated PDMS devices in de-ionized water would allow them to maintain their hydrophilicity for weeks. Atomic force microscopy analysis shows that a longer oxygen plasma time produces a smoother surface.
Advances in Rational Design and Materials of High‐Performance Stretchable Electromechanical Sensors
Publisher: Wiley
Date: 26-02-2020
Three-dimensional particle focusing under viscoelastic flow based on dean-flow-coupled elasto-inertial effects
Publisher: SPIE
Date: 26-01-2016
DOI: 10.1117/12.2211265
Analysis of chaotic mixing in plugs moving in meandering microchannels
Publisher: American Physical Society (APS)
Date: 12-12-2011
A Portable Device for LAMP Based Detection of SARS-CoV-2
Publisher: MDPI AG
Date: 24-09-2021
DOI: 10.3390/MI12101151
Abstract: This paper reports the design, development, and testing of a novel, yet simple and low-cost portable device for the rapid detection of SARS-CoV-2. The device performs loop mediated isothermal lification (LAMP) and provides visually distinguishable images of the fluorescence emitted from the s les. The device utilises an aluminium block embedded with a cartridge heater for isothermal heating of the s le and a single-board computer and camera for fluorescence detection. The device demonstrates promising results within 20 min using clinically relevant starting concentrations of the synthetic template. Time-to-signal data for this device are considerably lower compared to standard quantitative Polymerase Chain Reaction(qPCR) machine (~10–20 min vs. min) for 1 × 102 starting template copy number. The device in its fully optimized and characterized state can potentially be used as simple to operate, rapid, sensitive, and inexpensive platform for population screening as well as point-of-need severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) detection and patient management.
An analytical model for mixing based on time-interleaved sequential segmentation
Publisher: Springer Science and Business Media LLC
Date: 16-06-2005
High Throughput Cell-Free Extraction of Plasma by an Integrated Microfluidic Device Combining Inertial Microfluidics and Membrane
Publisher: American Society of Mechanical Engineers
Date: 04-01-2016
Abstract: Plasma is a host of various analytes such as proteins, metabolites, circulating nucleic acids (CNAs), pathogens. The key process of plasma extraction is to eliminate the contamination from blood cells. Conventional methods, such as centrifugation and membrane filtration, are generally lab-intensive, time consuming and even dangerous. In this study, we report an integrated microfluidic device that combines inertial microfluidics and membrane filter. The integrated microfluidic device was evaluated by the diluted (x1/10, x1/20) whole blood, and the quality of the extracted blood plasma was tested. It was found that quality of extracted blood plasma from integrated device was equivalent to that obtained by the centrifugation. This study demonstrates a significant progress towards the practical application of inertial microfluidics with membrane filter for high-throughput and high efficient blood plasma extraction.
Magnetofluidic spreading in circular chambers under a uniform magnetic field
Publisher: Springer Science and Business Media LLC
Date: 23-09-2020
Low-cost electrochemical paper-based device for exosome detection
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2AN00875K
Abstract: A low-cost electrochemical paper-based analytical device was developed to quantify cancer cell-derived exosomes.
Pneumatically actuated cell-stretching array platform for engineering cell patterns in vitro
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7LC01316G
Abstract: We report a pneumatically actuated cell-stretching well array to engineer cell patterns in vitro .
Novel approaches in cancer management with circulating tumor cell clusters
Publisher: Elsevier BV
Date: 03-2019
Development of a polymeric micro fuel cell containing laser-micromachined flow channels
Publisher: IOP Publishing
Date: 30-10-2004
Highly sensitive 3C-SiC on glass based thermal flow sensor realized using MEMS technology
Publisher: Elsevier BV
Date: 08-2018
Measuring the Coefficient of Friction of a Small Floating Liquid Marble
Publisher: Springer Science and Business Media LLC
Date: 02-12-2016
DOI: 10.1038/SREP38346
Abstract: This paper investigates the friction coefficient of a moving liquid marble, a small liquid droplet coated with hydrophobic powder and floating on another liquid surface. A floating marble can easily move across water surface due to the low friction, allowing for the transport of aqueous solutions with minimal energy input. However, the motion of a floating marble has yet to be systematically characterised due to the lack of insight into key parameters such as the coefficient of friction between the floating marble and the carrier liquid. We measured the coefficient of friction of a small floating marble using a novel experimental setup that exploits the non-wetting properties of a liquid marble. A floating liquid marble pair containing a minute amount magnetite particles were immobilised and then released in a controlled manner using permanent magnets. The capillarity-driven motion was analysed to determine the coefficient of friction of the liquid marbles. The “capillary charge” model was used to fit the experimental results. We varied the marble content and carrier liquid to establish a relationship between the friction correction factor and the meniscus angle.
Numerical and experimental investigations of the formation process of ferrofluid droplets
Publisher: Springer Science and Business Media LLC
Date: 05-03-2011
Hydrophobically Modified Gelatin Particles for Production of Liquid Marbles
Publisher: MDPI AG
Date: 19-10-2022
DOI: 10.20944/PREPRINTS202210.0282.V1
Abstract: The unique properties and morphology of liquid marbles (LMs) make them potentially useful for various applications. Non-edible hydrophobic organic polymer particles are widely used to prepare LMs. It is necessary to increase the variety of LM particles to extend their use into food and pharmaceuticals. Herein, we focus on hydrophobically modified gelatin (HMG) as a base material for the particles. The surface tension of HMG decreased as the length of alkyl chains incorporated into the gelatin and the degree of substitution (DS) of the alkyl chains increased. HMG with a surface tension of less than 37.5 mN/m (determined using equations based on the Young-Dupr& eacute equation and Kaelble-Uy theory) successfully formed LMs of water. The minimum surface tension of a liquid in which it was possible to form LMs using HMG particles was approximately 53 mN/m. We also showed that the liquid-over-solid spreading coefficient S_(L/S) is a potential new factor for predicting if particles can form LMs. The HMG particles and the new system for predicting LM formation could expand the use of LMs in food and pharmaceuticals.
Targeted Syntheses of Charged Porous Aromatic Frameworks for Iodine Enrichment and Release
Publisher: Shanghai Institute of Organic Chemistry
Date: 2016
DOI: 10.6023/A15080562
Interfacial Tension Measurement With an Optofluidic Sensor
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2007
Multiphysics microfluidics for cell manipulation and separation: a review
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1LC00869B
Abstract: We reviewed the state-of-the-art field of multiphysics microfluidics, in which multiple functional physical processes are combined in a microfluidic platform, examining the different formats of cascaded connections and physical coupling.
Lapatinib inhibits doxorubicin induced migration of HER2-positive breast cancer cells
Publisher: Springer Science and Business Media LLC
Date: 06-05-2020
Giant Piezotronic Effect by Photoexcitation–Electronic Coupling in a p-GaN/AlGaN/GaN Heterojunction
Publisher: American Chemical Society (ACS)
Date: 08-06-2022
Effect of resonator dimensions on nonlinear standing waves
Publisher: Acoustical Society of America (ASA)
Date: 2005
DOI: 10.1121/1.1828611
Abstract: An investigation of the effect of resonator dimensions on nonlinear standing waves in shaped resonators is conducted. Simple forms of the shear viscosity term in the momentum equations are developed for an axisymmetric (2D) resonator and a low aspect ratio rectangular (3D) resonator. The cross sections of the resonators are exponentially expanded and the one-dimensional wave equations are solved by using the Galerkin’s method. The quality factors, pressure waveforms, compression ratios, and resonance frequencies are calculated for different dimensionless cross sections and lengths of the resonators. The results show that, apart from the resonator length, the ratio of the cross-section dimension to the length of the resonator is an important parameter. If the ratio is greater than 0.04, the characteristics of the shaped resonator are not affected significantly. However, when the ratio is less than 0.01, the resonance becomes weak, the compression ratio drops substantially, and the frequency response changes as well.
Thermocapillary actuation of a water droplet encapsulated in an oil plug
Publisher: IOP Publishing
Date: 10-08-2007
Fabrication of planar nanofluidic channels in a thermoplastic by hot-embossing and thermal bonding
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B616134K
Abstract: Planar nanochannels are of particular significance in nanofluidics: keeping the width on the micrometre scale prevents the use of nanolithography while the depth stays in the nanometric range, i.e. below 100 nm. Fabrication of wide and shallow nanochannels in a plastic is known to be challenging due to the collapse of the structure during the sealing step. In this Technical Note, we demonstrate the simple and low-cost fabrication without nanolithography of monolithic and planar nanochannels by hot-embossing and bonding below the glass transition temperature.
Numerical Simulation of the Behavior of Toroidal and Spheroidal Multicellular Aggregates in Microfluidic Devices with Microwell and U-Shaped Barrier
Publisher: MDPI AG
Date: 11-12-2017
DOI: 10.3390/MI8120358
Formation and breakup of compound pendant drops at the tip of a capillary and its effect on upstream velocity fluctuations
Publisher: Elsevier BV
Date: 2012
One-dimensional actuation of a ferrofluid droplet by planar microcoils
Publisher: IOP Publishing
Date: 12-12-2009
Optical alignment of a cylindrical object
Publisher: IOP Publishing
Date: 20-01-2009
Generation of shock-free pressure waves in shaped resonators by boundary driving
Publisher: Acoustical Society of America (ASA)
Date: 05-2007
DOI: 10.1121/1.2713716
Abstract: Investigation of high litude pressure oscillations generated by boundary driving in shaped resonators has been carried out both theoretically and experimentally. In the theoretical modeling, the acoustic resonance in an axisymmetric resonator is studied by the Galerkin method. The resonator is exponentially expanded and the boundary driving is provided by a piston at one end. The pressure wave forms, litudes, resonance frequencies, and ratio of pressures at the two ends of the resonator are calculated for various expansion flare constants and driving strengths. These results are partially compared with those generated by shaking the resonator. They are also verified in the experiment, in which an exponentially expanded resonator is connected to a speaker box functioning as the piston. The experiment is further extended to a horn-shaped resonator with a rectangular cross section. The boundary driving in this case is generated by a circular piezoelectric disk, which forms one sidewall of the resonator cavity. The characteristics of axisymmetric resonators, such as the resonance frequency and litude ratio of pressures at the two ends, are observed in this low aspect ratio rectangular resonator with the sidewall driving.
Capillary Filling in Closed End Nanochannels
Publisher: American Chemical Society (ACS)
Date: 17-08-2010
DOI: 10.1021/LA1010902
Abstract: We investigated the interactions between liquid, gas, and solid phases in the capillary filling process of closed-end nanochannels. This paper presents theoretical models without and with absorption and diffusion of gas molecules in the liquid. Capillary filling experiments were carried out in closed-end silicon nanochannels with different lengths. The theoretical and measured characteristics of filling length versus time are compared. The results show that the filling process consists of two stages. The first stage resembles the capillary filling process in an open-end nanochannel. However, a remarkable discrepancy between the experimental results and the theory without gas absorption is observed in the second stage. A closer investigation of the second stage reveals that the dissolution of gas in the liquid is important and can be explained by the model with gas absorption and diffusion.
Sheathless Dean-flow-coupled elasto-inertial particle focusing and separation in viscoelastic fluid
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6RA25328H
Abstract: Sheathless particle focusing and separation in viscoelastic fluid is demonstrated using an integrated ECCA (straight channel section with asymmetrical expansion–contraction cavity arrays) straight channel.
Analysis on the birefringence property of lyotropic liquid crystals below Krafft temperature
Publisher: Elsevier BV
Date: 06-2011
Temperature dependence of interfacial properties and viscosity of nanofluids for droplet-based microfluidics
Publisher: IOP Publishing
Date: 12-03-2008
Challenge in particle delivery to cells in a microfluidic device
Publisher: Springer Science and Business Media LLC
Date: 21-12-2017
DOI: 10.1007/S13346-017-0467-3
Abstract: Micro and nanotechnology can potentially revolutionize drug delivery systems. Novel microfluidic systems have been employed for the cell culture applications and drug delivery by micro and nanocarriers. Cells in the microchannels are under static and dynamic flow perfusion of culture media that provides nutrition and removes waste from the cells. This exerts hydrostatic and hydrodynamic forces on the cells. These forces can considerably affect the functions of the living cells. In this paper, we simulated the flow of air, culture medium, and the particle transport and deposition in the microchannels under different angles of connection inlet. It was found that the shear stress induced by the medium culture flow is not so high to damage the cells and that it is roughly uniform in the cell culture section (CCS). However, the local shear stresses in the other parts of the microchip differ by changing the angles of the connection inlet. The results showed that the particle deposition was a function of the particle size, the properties of the fluid, and the flow rate. At a lower air flow rate, both small and large particles deposited in the entrance region and none of them reached the CCS. Once the airflow rate increased, the drag of the flow could overcome the diffusion of the small particles and deliver them to the CCS so that more than 88% of the 100 nm and 98% of the 200 nm particles deposited in the CCS. However, larger particles with average diameters in micrometers could not reach the CCS by the airflow even at high flow rate. In contrast, our findings indicated that both small and large particles could be delivered to the CCS by liquid flow. Our experimental data confirm that microparticles (with diameters of 5 and 20 μm) suspended in a liquid can reach the CCS at a well-adjusted flow rate. Consequently, a liquid carrier is suggested to transport large particles through microchannels. As a powerful tool, these numerical simulations provide a nearly complete understanding of the flow field and particle patterns in microchips which can significantly lower the trial and error in the experiment tests and accordingly save researchers considerable cost and time for drug delivery to the cell in the microchip by micro/nanocarriers.
Nanostructured mesoporous gold biosensor for microRNA detection at attomolar level
Publisher: Elsevier BV
Date: 11-2020
Dielectrophoretic Trapping of a Floating Liquid Marble
Publisher: American Physical Society (APS)
Date: 18-04-2019
PCR‐free detection of long non‐coding HOTAIR RNA in ovarian cancer cell lines and plasma samples
Publisher: MDPI AG
Date: 10-08-2020
Abstract: Long non-coding RNA HOX transcript antisense intergenic RNA (HOTAIR) is one of the promising biomarkers that has widely been used in determining the stages of many cancers, including ovarian cancer. In cancer diagnostics, the two key analytical challenges for detecting long non-coding RNA biomarkers are i) the low concentration levels (nM to fM range) in which they are found and ii) the analytical method where broad dynamic range is required (four to six orders of magnitude) due to the large variation in expression levels for different HOTAIR RNAs. To meet these challenges, we report on a biosensing platform for the visual (colorimetric) estimation and subsequent electrochemical quantification of ovarian-cancer-specific HOTAIR using a screen-printed gold electrode (SPE-Au). Our assay utilizes a two-step strategy that involves (i) magnetic isolation and purification of target HOTAIR sequences and (ii) subsequent detection of isolated sequences using a sandwich hybridization coupled with horseradish peroxidase (HRP)-catalyzed reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide. The assay achieved a detection limit of 1.0 fM HOTAIR in spiked buffer s les with excellent reproducibility (% RSD ≤ 5%, for n = 3). It was successfully applied to detect HOTAIR in cancer cell lines and a panel of plasma s les derived from patients with ovarian cancer. The analytical performance of the method was validated with standard RT-qPCR. We believe that the proof of concept assay reported here may find potential use in routine clinical settings for the screening of cancer-related lncRNAs.
Frequency Reconfigurable Smart Antenna With Integrated Electroactive Polymer for Far-Field Communication
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 02-2022
Nonlinear standing waves in a resonator with feedback control
Publisher: Acoustical Society of America (ASA)
Date: 07-2007
DOI: 10.1121/1.2735808
Abstract: An experimental study is presented to demonstrate that nonlinear effect on standing waves in a resonator can be reduced by a feedback loop responding to the second harmonic. The resonator was a cylindrical tube sealed at one end and driven by a horn driver unit at another end. The feedback control loop consisted of a pressure sensor, a frequency filter, a phase shifter, and an actuator. The results show that the waveform distortions can be eliminated and large litude sinusoidal pressure oscillations are obtained. A simple model is proposed for a qualitative discussion on the control mechanism, which shows that the feedback loop alters the imaginary part of the complex mode frequency so as to suppress (or enhance) the second harmonic.
Loop-Mediated Isothermal Amplification in Core-Shell Beads Assay for the Detection of Tyrosine Kinase AXL Over Expression
Publisher: MDPI AG
Date: 08-07-2021
DOI: 10.20944/PREPRINTS202107.0195.V1
Abstract: The upregulated expression of thyrosine kinase AXL has been reported in several hematologic and solid human tumors including gastric, breast, colorectal, prostate, and ovarian cancers. Thus, AXL can potentially serve as a diagnostic and prognostic biomarker for various cancers. This paper reports the first-ever use of loop-mediated isothermal lification (LAMP) of the AXL gene as a diagnostic method for ovarian cancer. We demonstrated simple instrumentation toward a point-of-care device to perform LAMP. This paper also reports the first-ever use of core-shell beads as a microreactor to perform LAMP as an attempt to promote environmentally friendly laboratory practices.
Active droplet generation in microfluidics
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5LC01012H
Abstract: This review presents the state of the art of active microfluidic droplet generation concepts.
Temperature-induced droplet coalescence in microchannels
Publisher: AIP Publishing
Date: 03-2012
DOI: 10.1063/1.3630124
Abstract: This paper reports a technique for temperature-induced merging of droplets in a microchannel. The multiphase system consists of water droplet and oil as the dispersed phase and the carrying continuous phase. A resistive heater provides heating in a rectangular merging chamber. The temperature of the chamber is controlled by the voltage applied to the heater. The merging process of two neighboring droplets was investigated with different applied voltage, flow rate ratio between water and oil and total flowrate. Merging is found to be effective at high flow rate ratio, high temperature, and low total flowrate. The presented technique could be used for merging and mixing in droplet-based lab-on-a-chip platforms
Core-Shell Beads as Microreactors for Phylogrouping of E. coli Strains
Publisher: MDPI AG
Date: 07-08-2020
DOI: 10.3390/MI11080761
Abstract: Multiplex polymerase chain reaction (PCR) is an effective tool for simultaneous detection of target genes. Nevertheless, their use has been restricted due to the intrinsic interference between primer pairs. Performing several single PCRs in an array format instead of a multiplex PCR is a simple way to overcome this obstacle. However, there are still major technical challenges in designing a new generation of single PCR microreactors with a small s le volume, rapid thermal cycling, and no evaporation during lification. We report a simple and robust core-shell bead array for a series of single lifications. Four core-shell beads with a polymer coating and PCR mixture were synthesized using liquid marble formation and subsequent photo polymerization. Each bead can detect one target gene. We constructed a customised system for thermal cycling of these core-shell beads. Phylogrouping of the E. coli strains was carried out based on the fluorescent signal of the core-shell beads. This platform can be a promising alternative for multiplex nucleic acid analyses due to its simplicity and high throughput. The platform reported here also reduces the cycling time and avoids evaporation as well as contamination of the s le during the lification process.
Thermally mediated breakup of drops in microchannels
Publisher: AIP Publishing
Date: 04-12-2006
DOI: 10.1063/1.2400200
Abstract: The authors used thermally induced surface tension gradients to manipulate aqueous droplets in microchannels. Control of the droplet breakup process was demonstrated. Droplet sorting can be achieved with temperatures above a critical value. Numerical simulation using a two-dimensional model agrees qualitatively well with the experimental results. The used control temperature of less than 55°C shows that this active control concept is suitable for biochemical applications. Thermal control promises to be a simple and effective manipulation method for droplet-based lab on a chip.
Microcalorimeter: Design considerations, materials and examples
Publisher: Elsevier BV
Date: 06-2016
Surface Modification Techniques for Endothelial Cell Seeding in PDMS Microfluidic Devices
Publisher: MDPI AG
Date: 19-11-2020
DOI: 10.3390/BIOS10110182
Abstract: Microfluidic lab-on-a-chip cell culture techniques have been gaining popularity by offering the possibility of reducing the amount of s les and reagents and greater control over cellular microenvironment. Polydimethylsiloxane (PDMS) is the commonly used polymer for microfluidic cell culture devices because of the cheap and easy fabrication techniques, non-toxicity, biocompatibility, high gas permeability, and optical transparency. However, the intrinsic hydrophobic nature of PDMS makes cell seeding challenging when applied on PDMS surface. The hydrophobicity of the PDMS surface also allows the non-specific absorption/adsorption of small molecules and biomolecules that might affect the cellular behaviour and functions. Hydrophilic modification of PDMS surface is indispensable for successful cell seeding. This review collates different techniques with their advantages and disadvantages that have been used to improve PDMS hydrophilicity to facilitate endothelial cells seeding in PDMS devices.
Toward on-board microchip synthesis of CdSe: Vs. PbSe nanocrystalline quantum dots as a spectral decoy for protecting space assets
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0RE00327A
Abstract: Fabrication of the reaction chamber using silicon carbide. (A) A schematic sketch of the fabrication flow (B) a photograph of a transparent 6 inch SiC-on-glass wafer (C) the surface morphology of the SiC film.
Micromagnetic resonance relaxometry for rapid label-free malaria diagnosis
Publisher: Springer Science and Business Media LLC
Date: 31-08-2014
DOI: 10.1038/NM.3622
Wide-Band-Gap Semiconductors for Biointegrated Electronics: Recent Advances and Future Directions
Publisher: American Chemical Society (ACS)
Date: 19-04-2021
Three-Dimensional Modeling of Avascular Tumor Growth in Both Static and Dynamic Culture Platforms
Publisher: MDPI AG
Date: 31-08-2019
DOI: 10.3390/MI10090580
Abstract: Microfluidic cell culture platforms are ideal candidates for modeling the native tumor microenvironment because they can precisely reconstruct in vivo cellular behavior. Moreover, mathematical modeling of tumor growth can pave the way toward description and prediction of growth pattern as well as improving cancer treatment. In this study, a modified mathematical model based on concentration distribution is applied to tumor growth in both conventional static culture and dynamic microfluidic cell culture systems. Apoptosis and necrosis mechanisms are considered as the main inhibitory factors in the model, while tumor growth rate and nutrient consumption rate are modified in both quiescent and proliferative zones. We show that such modification can better predict the experimental results of tumor growth reported in the literature. Using numerical simulations, the effects of the concentrations of the nutrients as well as the initial tumor radius on the tumor growth are investigated and discussed. Furthermore, tumor growth is simulated by taking into account the dynamic perfusion into the proposed model. Subsequently, tumor growth kinetics in a three-dimensional (3D) microfluidic device containing a U-shaped barrier is numerically studied. For this case, the effect of the flow rate of culture medium on tumor growth is investigated as well. Finally, to evaluate the impact of the trap geometry on the tumor growth, a comparison is made between the tumor growth kinetics in two frequently used traps in microfluidic cell culture systems, i.e., the U-shaped barrier and microwell structures. The proposed model can provide insight into better predicting the growth and development of avascular tumor in both static and dynamic cell culture platforms.
Engineering microfluidic concentration gradient generators for biological applications
Publisher: Springer Science and Business Media LLC
Date: 24-07-2013
Modeling and optimization of planar microcoils
Publisher: IOP Publishing
Date: 05-08-2008
A polymeric high-throughput pressure-driven micromixer using a nanoporous membrane
Publisher: Springer Science and Business Media LLC
Date: 02-09-2011
Formation of core–shell droplets for the encapsulation of liquid contents
Publisher: Springer Science and Business Media LLC
Date: 03-09-2021
Wirelessly activated device with an integrated ionic polymer metal composite (IPMC) cantilever valve for targeted drug delivery
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8LC00776D
Abstract: A wirelessly activated ionic polymer metal composite (IPMC) releases cisplatin drug from the device's orifice shows decrease of HeLa cell viability with RF turned on.
Investigation of Thermal Flow Sensor Based on Laser Induced Fluorescence Technique
Publisher: Bentham Science Publishers Ltd.
Date: 03-2011
Image segmentation based on adaptive cluster prototype estimation
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2005
Investigation of forced convection in microfluid systems
Publisher: Elsevier BV
Date: 07-1996
Editorial for the Special Issue of 10th Anniversary of Micromachines
Publisher: MDPI AG
Date: 24-12-2020
DOI: 10.3390/MI12010009
Abstract: Micromachines published its inaugural issue in 2010 it has experienced a tremendous growth in both the quantity and quality of its scientific papers [...]
Transparent crystalline cubic SiC-on-glass electrodes enable simultaneous electrochemistry and optical microscopy
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CC03082D
Abstract: This work introduces transparent SiC-on-glass as a new platform for biosensing applications which enables cell culturing, stimulating, microscopy-imaging and bioelectrochemical detection.
Flexible microfluidics: Fundamentals, recent developments, and applications
Publisher: MDPI AG
Date: 29-11-2019
DOI: 10.3390/MI10120830
Abstract: Miniaturization has been the driving force of scientific and technological advances over recent decades. Recently, flexibility has gained significant interest, particularly in miniaturization approaches for biomedical devices, wearable sensing technologies, and drug delivery. Flexible microfluidics is an emerging area that impacts upon a range of research areas including chemistry, electronics, biology, and medicine. Various materials with flexibility and stretchability have been used in flexible microfluidics. Flexible microchannels allow for strong fluid-structure interactions. Thus, they behave in a different way from rigid microchannels with fluid passing through them. This unique behaviour introduces new characteristics that can be deployed in microfluidic applications and functions such as valving, pumping, mixing, and separation. To date, a specialised review of flexible microfluidics that considers both the fundamentals and applications is missing in the literature. This review aims to provide a comprehensive summary including: (i) Materials used for fabrication of flexible microfluidics, (ii) basics and roles of flexibility on microfluidic functions, (iii) applications of flexible microfluidics in wearable electronics and biology, and (iv) future perspectives of flexible microfluidics. The review provides researchers and engineers with an extensive and updated understanding of the principles and applications of flexible microfluidics.
Thermally mediated droplet formation in microchannels
Publisher: AIP Publishing
Date: 20-08-2007
DOI: 10.1063/1.2773948
Abstract: Precise dispensing of microdroplets is an important process for droplet-based microfluidics. The droplet formation by shear force between two immiscible fluids depends on their flow rates, the viscosities, and the interfacial tension. In this letter, the authors report the use of integrated microheater and temperature sensor for controlling the droplet formation process. The technique exploits the dependency on temperature of viscosities and interfacial tension. Using a relatively low heating temperature ranging from 25to70°C, the droplet diameter can be adjusted to over two times of its original value. The relatively low temperature range makes sure that this concept is applicable for droplets containing biological s les.
Rapid magnetofluidic mixing in a uniform magnetic field
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2LC40818J
Abstract: This paper reports the investigation of mixing phenomena caused by the interaction between a uniform magnetic field and a magnetic fluid in a microfluidic chamber. The flow system consists of a water-based ferrofluid and a mixture of DI water and glycerol. Under a uniform magnetic field, the mismatch in magnetization of the fluids leads to instability at the interface and subsequent rapid mixing. The mismatch of magnetization is determined by concentration of magnetic nanoparticles. Full mixing at a relatively low magnetic flux density up to 10 mT can be achieved. The paper discusses the impact of key parameters such as magnetic flux density, flow rate ratio and viscosity ratio on the mixing efficiency. Two main mixing regimes are observed. In the improved diffusive mixing regime under low field strength, magnetic particles of the ferrofluid migrate into the diamagnetic fluid. In the bulk transport regime under high field strength, the fluid system is mixed rapidly by magnetically induced secondary flow in the chamber. The mixing concept potentially provides a wireless solution for a lab-on-a-chip system that is low-cost, robust, free of induced heat and independent of pH level or ion concentration.
Heat transfer enhancement by recirculating flow within liquid plugs in microchannels
Publisher: Elsevier BV
Date: 03-2012
Front Cover: Investigation of liquid marble shell using X‐ray: shell thickness and effective surface tension (ChemNanoMat 1/2022)
Publisher: Wiley
Date: 09-12-2022
Thermocapillary actuation and cycling of liquid plugs
Publisher: ASMEDC
Date: 2008
Abstract: With the aim toward realizing polymerase chain reaction (PCR) of deoxyribonucleic acid (DNA) in plug-based capillary platforms, this paper reports the theoretical and experimental results of thermocapillary actuation for temperature cycling with an arbitrary r ing function. Two concepts were investigated: (a) actuation and spatial temperature cycling with three heaters and (b) actuation and temporal cycling with two heaters. The paper first describes the analytical models of both concepts. The model considers both the transient and coupling effect between heat transfer in the capillary wall and the surface tension driven movement of the plug. In the experiments, both temperature field and plug motion were measured and evaluated. The temperature field were captured by an infrared thermo tracer camera. The position of the plugs was automatically captured and evaluated with a CCD camera. Finally, analytical and experimental results are compared and discussed.
Accurate dielectrophoretic positioning of a floating liquid marble with a two-electrode configuration
Publisher: Springer Science and Business Media LLC
Date: 03-06-2019
A Stepper Micropump for Ferrofluid Driven Microfluidic Systems
Publisher: Bentham Science Publishers Ltd.
Date: 03-2009
Quantification of gene-specific DNA methylation in oesophageal cancer via electrochemistry
Publisher: Elsevier BV
Date: 07-2017
DOI: 10.1016/J.ACA.2017.04.034
Abstract: Development of simple and inexpensive method for the analysis of gene-specific DNA methylation is important for the diagnosis and prognosis of patients with cancer. Herein, we report a relatively simple and inexpensive electrochemical method for the sensitive and selective detection of gene-specific DNA methylation in oesophageal cancer. The underlying principle of the method relies on the affinity interaction between DNA bases and unmodified gold electrode. Since the affinity trend of DNA bases towards the gold surface follows as adenine (A) > cytosine (C) > guanine (G)> thymine (T), a relatively larger amount of bisulfite-treated adenine-enriched unmethylated DNA adsorbs on the screen-printed gold electrodes (SPE-Au) in comparison to the guanine-enriched methylated s le. The methylation levels were (i.e., different level of surface attached DNA molecules due to the base dependent differential adsorption pattern) quantified by measuring saturated amount of charge-compensating [Ru(NH
Nonlinear Deformation of a Ferrofluid Droplet in a Uniform Magnetic Field
Publisher: American Chemical Society (ACS)
Date: 15-11-2011
DOI: 10.1021/LA203931Q
Abstract: This paper reports experimental and numerical results of the deformation of a ferrofluid droplet on a superhydrophobic surface under the effect of a uniform magnetic field. A water-based ferrofluid droplet surrounded by immiscible mineral oil was stretched by a magnetic field parallel to the substrate surface. The results show that an increasing flux density increases the droplet width and decreases the droplet height. A numerical model was established to study the equilibrium shape of the ferrofluid droplet. The governing equations for physical fields, including the magnetic field, are solved by the finite volume method. The interface between the two immiscible liquids was tracked by the level-set method. Nonlinear magnetization was implemented in the model. Comparison between experimental and numerical results shows that the numerical model can predict well the nonlinear deformation of a ferrofluid droplet in a uniform magnetic field.
Challenges and perspectives in the development of paper-based lateral flow assays
Publisher: Springer Science and Business Media LLC
Date: 02-2020
Thermocapillary actuation of liquid plugs using a heater array
Publisher: Elsevier BV
Date: 11-2007
ScAlN/3C-SiC/Si platform for monolithic integration of highly sensitive piezoelectric and piezoresistive devices
Publisher: AIP Publishing
Date: 30-03-2020
DOI: 10.1063/5.0004943
Abstract: This paper reports on a platform for monolithic integration of piezoelectric and piezoresistive devices on a single chip using the ScAlN/3C-SiC/Si heterostructure. Surface acoustic wave devices with an electromechanical coupling of 3.2% and an out-of-band rejection as high as 18 dB are demonstrated using the excellent piezoelectric properties of ScAlN and low acoustic loss of 3C-SiC. Additionally, a large piezoresistive effect in the low-doped n-type 3C-SiC(100) thin film has been observed, which exceeds the previously reported values in any SiC thin films. The growth of the n-type 3C-SiC thin film was performed using the low pressure chemical vapor deposition technique at 1250 °C and the standard micro-electro-mechanical systems process is used for the fabrication of 3C-SiC piezoresistors. The piezoresistive effect was measured using the bending beam method in different crystallographic orientations. The maximum gauge factor is –47 for the longitudinal [100] orientation. Using the longitudinal and transverse gauge factors for different crystallographic orientations, the fundamental piezoresistive coefficients of the low-doped n-type 3C-SiC thin film are measured to be π11=(−14.5±1.3)×10−11 Pa−1, π12=(5.5±0.5)×10−11 Pa−1, and π44=(−1.7±0.7)×10−11 Pa−1.
Coalescence processes of droplets and liquid marbles
Publisher: MDPI AG
Date: 20-11-2017
DOI: 10.3390/MI8110336
Investigation of heat transfer in a microchannel with same heat capacity rate
Publisher: Springer Science and Business Media LLC
Date: 07-09-2018
Wicking in Paper Strips under Consideration of Liquid Absorption Capacity
Publisher: MDPI AG
Date: 06-08-2020
DOI: 10.3390/CHEMOSENSORS8030065
Abstract: Paper-based microfluidic devices have the potential of being a low-cost platform for diagnostic devices. Electrical circuit analogy (ECA) model has been used to model the wicking process in paper-based microfluidic devices. However, material characteristics such as absorption capacity cannot be included in the previous ECA models. This paper proposes a new model to describe the wicking process with liquid absorption in a paper strip. We observed that the fluid continues to flow in a paper strip, even after the fluid reservoir has been removed. This phenomenon is caused by the ability of the paper to store liquid in its matrix. The model presented in this paper is derived from the analogy to the current response of an electric circuit with a capacitance. All coefficients in the model are fitted with data of capillary rise experiments and compared with direct measurement of the absorption capacity. The theoretical data of the model agrees well with experimental data and the conventional Washburn model. Considering liquid absorption capacity as a capacitance helps to explain the relationship between material characteristics and the wicking mechanism.
Microneedle Arrays for Sampling and Sensing Skin Interstitial Fluid
Publisher: MDPI AG
Date: 16-04-2021
DOI: 10.3390/CHEMOSENSORS9040083
Abstract: Dermal interstitial fluid (ISF) is a novel source of biomarkers that can be considered as an alternative to blood s ling for disease diagnosis and treatment. Nevertheless, in vivo extraction and analysis of ISF are challenging. On the other hand, microneedle (MN) technology can address most of the challenges associated with dermal ISF extraction and is well suited for long-term, continuous ISF monitoring as well as in situ detection. In this review, we first briefly summarise the different dermal ISF collection methods and compare them with MN methods. Next, we elaborate on the design considerations and biocompatibility of MNs. Subsequently, the fabrication technologies of various MNs used for dermal ISF extraction, including solid MNs, hollow MNs, porous MNs, and hydrogel MNs, are thoroughly explained. In addition, different sensing mechanisms of ISF detection are discussed in detail. Subsequently, we identify the challenges and propose the possible solutions associated with ISF extraction. A detailed investigation is provided for the transport and s ling mechanism of ISF in vivo. Also, the current in vitro skin model integrated with the MN arrays is discussed. Finally, future directions to develop a point-of-care (POC) device to s le ISF are proposed.
Fabrication and characterization of low-cost, bead-free, durable and hydrophobic electrospun membrane for 3D cell culture
Publisher: Springer Science and Business Media LLC
Date: 22-08-2017
DOI: 10.1007/S10544-017-0215-Y
Abstract: This paper reports the fabrication of electrospun polydimethylsiloxane (PDMS) membranes/scaffolds that are suitable for three-dimensional (3D) cell culture. Through modification the ratio between PDMS and polymethylmethacrylate (PMMA) as carrier polymer, we report the possibility of increasing PDMS weight ratio of up to 6 for electrospinning. Increasing the PDMS content increases the fiber diameter, the pore size, and the hydrophobicity. To our best knowledge, this is the first report describing beads-free, durable and portable electrospun membrane with maximum content of PDMS suitable for cell culture applications. To show the proof-of-concept, we successfully cultured epithelial lung cancer cells on these membranes in a static well plate without surface modification. Surprisingly, due to three-dimensional (3D) and hydrophobic nature of the electrospun fibers, cells aggregated into 3D multicellular spheroids. These easily detachable and cost-effective scaffolds with controllable thicknesses and high tensile strength are good candidates for cell-stretching devices, organ-on-a-chip devices, tissue engineering and studies of non-adherent mammalian cancer stem cells.
Degraded boiling heat transfer from hotwire in ferrofluid due to particle deposition
Publisher: Elsevier BV
Date: 09-2018
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University Of Derby
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