ORCID Profile
0000-0002-5419-9508
Current Organisation
Harbin Institute of Technology (Shenzhen)
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Publisher: Springer Science and Business Media LLC
Date: 05-06-2001
Publisher: Wiley
Date: 22-04-2014
DOI: 10.1002/APP.40797
Abstract: Electrospinning is an economical and relatively simple method to produce continuous and uniform nanofibers from almost any synthetic and many natural polymers. Because of the high specific surface area, tunable pore size, and flexibility, the nanofibrous membranes are finding an increasingly wide range of applications. Some particular attention has been devoted to antibacterial nanofibers for applications such as wound dressings. A variety of biocides, e.g ., antibiotics, quaternary ammonium salts, triclosan, biguanides, (silver, titanium dioxide, and zinc oxide) nanoparticles and chitosan have been incorporated by various techniques into nanofibers that exhibit strong antibacterial activity in standard assays. However, the small diameters of the nanofibers also mean that the incorporated biocides are often burst released once the materials are submerged in an aqueous solution. Nevertheless, several strategies, such as core‐sheath structure of the nanofiber, covalent bonding of the biocide on the fiber surface and adsorption of the biocide in nanostructures, can be utilized to sustain the release over several days. This review summarizes recent development in the fabrication of antibacterial nanofibers, the release profiles of the biocides and their applications in in vivo systems. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 40797.
Publisher: Springer Science and Business Media LLC
Date: 27-05-2014
DOI: 10.1038/SREP05060
Publisher: Elsevier BV
Date: 2018
Publisher: SPIE
Date: 21-12-2011
DOI: 10.1117/12.903211
Publisher: Informa UK Limited
Date: 08-2010
Publisher: Wiley
Date: 27-08-2010
Abstract: Fluorongenic reagents based on 4-methylumbelliferone (4-MU) have been widely used for the detection of phosphatase, sulfatase, esterase, lipase and glycosidase activities in conventionally formatted enzyme assay systems. However, the sensitivity of assays based on these substrates is also potentially very useful in the microdroplet formats now being developed for high throughput in vitro evolution experiments. In this article, we report the investigation of diffusion of 4-MU as a model dye from water-in-oil droplets and the internal aqueous phase of water-in-oil-in-water droplets in microfluidics. The effect of BSA in the aqueous phase on the diffusion of 4-MU is also discussed. Based on these results, we provided here proof-of-concept of the reaction of the enzyme OpdA with the substrate coumaphos in water-in-oil-in-water droplets. In this double-emulsion system, the reaction of OpdA and coumaphos was achieved by allowing coumaphos to diffuse from the continuous aqueous phase across the oil phase into the internal aqueous droplets.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2RE00103A
Abstract: A low-cost 3D micromixer was developed using a desktop-class 3D printer and it demonstrated unprecedented mixing performance over the widest range of flow conditions.
Publisher: SPIE
Date: 21-12-2011
DOI: 10.1117/12.903213
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6RA25509D
Abstract: Separation of minor hydrocarbon components in natural gas is necessary prior to liquefaction to avoid operational (plugging of equipment) and product specification issues.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7NR01511A
Abstract: Surface-Enhanced Raman Scattering (SERS) is emerging as a promising strategy for the quantification of immunoglobulin G (IgG) due to its inherent high sensitivity and specificity however, it remains challenging to integrate SERS detection with a microfluidic system in a simple, efficient and low-cost manner. Here, we report on a novel bifunctional plasmonic-magnetic particle-based immunoassay, in which plasmonic nanoparticles act as soluble SERS immunosubstrates, whereas magnetic particles are for promoting micromixing in a microfluidic chip. With this novel SERS immunosubstrate in conjunction with the unique microfluidic system, we could substantially reduce the assay time from 4 hours to 80 minutes as well as enhance the detection specificity by about 70% in comparison to a non-microfluidic immunoassay. Compared to previous microfluidic SERS systems, our strategy offers a simple microfluidic chip design with only one well for mixing, washing and detection.
Publisher: MDPI AG
Date: 16-10-2022
DOI: 10.3390/BIOS12100878
Abstract: The micropillar array electrode (µAE) has been widely applied in microchip-based electrochemical detection systems due to a large current response. However, it was found that lifying the current through further adjusting geometrical parameters is generally hindered by the shielding effect. To solve this problem, a bio-inspired micropillar array electrode (bµAE) based on the microfluidic device has been proposed in this study. The inspiration is drawn from the structure of leatherback sea turtles’ mouths. By deforming a μAE to rearrange the micropillars on bilateral sides of the microchannel, the contact area between micropillars and analytes increases, and thus the current is substantially improved. A numerical simulation was then used to characterize the electrochemical performance of bµAEs. The effects of geometrical and hydrodynamic parameters on the current of bµAEs were investigated. Moreover, a prototypical microchip integrated with bµAE was fabricated for detailed electrochemical measurement. The chrono erometry measurements were conducted to verify the theoretical performance of bµAEs, and the results suggest that the experimental data are in good agreement with those of the simulation model. This work presents a novel bµAE with great potential for highly sensitive electrochemical detection and provides a new perspective on the efficient configuration of the µAE.
Publisher: Elsevier BV
Date: 08-2019
Publisher: Wiley
Date: 02-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9RA03028J
Abstract: A droplet-based microfluidic needle-like probe has been designed and applied for on-site hydrogen peroxide (H 2 O 2 ) s ling, reaction and detection using a commercial, single-step fluorescent H 2 O 2 assay.
Publisher: Springer Berlin Heidelberg
Date: 2008
DOI: 10.1007/10_2008_098
Abstract: In vitro compartmentalization (IVC) is a powerful tool for studying protein-protein reactions, due to its high capacity and the versatility of droplet technologies. IVC bridges the gap between chemistry and biology as it enables the incorporation of unnatural amino acids with modifications into biological systems, through protein transcription and translation reactions, in a cell-like microdrop environment. The quest for the ultimate chip for protein studies using IVC is the drive for the development of various microfluidic droplet technologies to enable these unusual biochemical reactions to occur. These techniques have been shown to generate precise microdrops with a controlled size. Various chemical and physical phenomena have been utilized for on-chip manipulation to allow the droplets to be generated, fused, and split. Coupled with detection techniques, droplets can be sorted and selected. These capabilities allow directed protein evolution to be carried out on a microchip. With further technological development of the detection module, factors such as addressable storage, transport and interfacing technologies, could be integrated and thus provide platforms for protein studies with high efficiency and accuracy that conventional laboratories cannot achieve.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0RA07694E
Abstract: PDMS-based micropillar array electrodes with increased surface area and surface modification were developed to detect biomarkers with high sensitivity.
Publisher: MDPI AG
Date: 16-09-2019
DOI: 10.3390/MI10090617
Abstract: The rapid and reliable detection of chemical and biological agents in the field is important for many applications such as national security, environmental monitoring, infectious diseases screening, and so on. Current commercially available devices may suffer from low field deployability, specificity, and reproducibility, as well as a high false alarm rate. This paper reports the development of a portable lab-on-a-chip device that could address these issues. The device integrates a polymer multiplexed microchip system, a contactless conductivity detector, a data acquisition and signal processing system, and a graphic/user interface. The s les are pre-treated by an on-chip capillary electrophoresis system. The separated analytes are detected by conductivity-based microsensors. Extensive studies are carried out to achieve satisfactory reproducibility of the microchip system. Chemical warfare agents soman (GD), sarin (GB), O-ethyl S-[2-diisoproylaminoethyl] methylphsophonothioate (VX), and their degradation products have been tested on the device. It was demonstrated that the device can fingerprint the tested chemical warfare agents. In addition, the detection of ricin and metal ions in water s les was demonstrated. Such a device could be used for the rapid and sensitive on-site detection of both chemical and biological agents in the future.
Publisher: AIP Publishing
Date: 10-1995
DOI: 10.1063/1.868690
Abstract: The effect of suction, applied through a short porous wall strip, on a low Reynolds number self-preserving turbulent boundary layer has been quantified by measuring the local wall shear stress and the main Reynolds stresses downstream of the strip. When the suction rate is sufficiently high, pseudo-relaminarization occurs almost immediately downstream of the strip. Farther downstream, transition occurs followed by a slow return to a fully turbulent self-preserving state. During relaminarization, the measured skin friction coefficient cf falls below the level corresponding to the no suction value, reaching a minimum where transition begins. An empirical cf distribution is proposed that groups together results obtained at different streamwise stations and different suction rates. Of all the measured Reynolds stresses, the longitudinal turbulence intensity recovers relatively quickly from the change in boundary conditions while the wall-normal turbulence intensity and the Reynolds shear stress are significantly affected by the suction. The Reynolds shear stress, which is negligible during relaminarization, has the slowest recovery.
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B911581A
Abstract: Droplet based microfluidics are promising new tools for biological and chemical assays. In this paper, a high throughput and high sensitivity microfluidic droplet platform is described for in vitro protein expression using crude Escherichia coli S30 extract. A flow-focusing polymethylmethacrylate (PMMA) microchip was designed and integrated with different functions involving droplet generation, storage, separation and detection. The material used for the chip is superior to the previously tested polydimethylsiloxane (PDMS) due to its mechanical and chemical properties. Droplet formation characteristics such as size and generation rate are investigated systematically. The effect of surfactants Abil EM90 and Span80 in the oil phase on droplet formation and optical detection is also studied. The performance of the system is demonstrated by the high throughput and stable droplet generation and ultralow detection limit. The robustness of the system is also demonstrated by the successful synthesis of a green fluorescent protein (GFP) using E. coli S30 extract as a source of RNA translation reagents.
Publisher: SPIE
Date: 26-12-2008
DOI: 10.1117/12.810767
Publisher: Wiley
Date: 08-02-2023
Abstract: Micromixers play an important role in the micro total analysis systems (µTAS) that require rapid and effective mixing. However, current micromixers are usually designed to meet the need for mixing at limited Reynolds numbers. Herein, this paper presents a high‐performance 3D micromixer with helical elements over wide Reynolds numbers to achieve efficient mixing and has numerically investigated flow patterns and mixing characteristics accordingly. A coupled numerical model is built to analyze the flow pattern, mixing behavior, residence time distribution (RTD), and mixing performance of the 3D micromixer. Helical elements inside could greatly enhance a secondary flow and induce chaotic advection around. Dean vortices are observed in the micromixer, enormously shortening the RTD and promoting the related mixing effect. Furthermore, the effects of various geometric parameters are systematically investigated to optimize the performance of this 3D micromixer. The optimized micromixer shows excellent mixing ability over wide Reynolds numbers ranging from 0.01 to 2333.3, with an efficiency of over 94%. In addition, the numerical results are proved well consistent with analytical and experimental data correspondingly. Therefore, this work would potentially expand the use scope of 3D micromixers and provide a constructive strategy to develop essential parts involving the mixing or reacting process in µTAS.
Publisher: Springer Science and Business Media LLC
Date: 09-1994
DOI: 10.1007/BF00713779
Publisher: AIP Publishing
Date: 03-2022
DOI: 10.1063/5.0084415
Abstract: Understanding the dynamics of airflow in alveoli and its effect on the behavior of particle transport and deposition is important for understanding lung functions and the cause of many lung diseases. The studies on these areas have drawn substantial attention over the last few decades. This Review discusses the recent progress in the investigation of behavior of airflow in alveoli. The information obtained from studies on the structure of the lung airway tree and alveolar topology is provided first. The current research progress on the modeling of alveoli is then reviewed. The alveolar cell parameters at different generation of branches, issues to model real alveolar flow, and the current numerical and experimental approaches are discussed. The findings on flow behavior, in particular, flow patterns and the mechanism of chaotic flow generation in the alveoli are reviewed next. The different flow patterns under different geometrical and flow conditions are discussed. Finally, developments on microfluidic devices such as lung-on-a-chip devices are reviewed. The issues of current devices are discussed.
Publisher: Elsevier BV
Date: 02-2019
Publisher: Cambridge University Press (CUP)
Date: 25-09-1996
DOI: 10.1017/S0022112096000882
Abstract: The accurate measurement of vorticity has proven difficult because of the difficulty of estimating spatial derivatives of velocity fluctuations reliably. A method is proposed for correcting the lateral vorticity spectrum measured using a four-wire probe. The attenuation of the measured spectrum increases as the wavenumber increases but does not vanish when the wavenumber is zero. Although the correction procedure assumes local isotropy, the major contributor to the high-wavenumber part of the vorticity spectrum is the streamwise derivative of the lateral velocity fluctuation, and the correction of this latter quantity does not depend on local isotropy. Satisfactory support for local isotropy is provided by the high-wavenumber parts of the velocity, velocity derivative and vorticity spectra measured on the centreline of a turbulent wake. Second- and fourth-order moments of vorticity show departures from local isotropy but the degree of departure seems unaffected by the turbulence Reynolds number R λ . The vorticity probability density function is approximately exponential and has tails which stretch out to larger litudes as R λ increases. The vorticity flatness factor, which is appreciably larger than the flatness factor of the streamwise velocity derivative, also increases with R λ . When R λ is sufficiently large for velocity structure functions to indicate a r 2/3 inertial range, two-point longitudinal correlations of lateral vorticity fluctuations give encouraging support for the theoretical r −4/3 behaviour.
Publisher: MDPI AG
Date: 20-03-2022
DOI: 10.3390/MI13030485
Abstract: Understanding the mechanism of particle transport and sedimentation in pulmonary alveolus is important for deciphering the causes of respiratory diseases and helping the development of drug delivery. In this study, taking advantage of the microfluidic technique, an experimental platform was developed to study particle behavior in a rhythmically expanding alveolar chip for a sufficient number of cycles. The alveolar flow patterns at different generations were measured for two cases with the gravity direction parallel or vertical to the alveolar duct. Affected by both the vortex flow inside the alveoli and the shear flow in the duct simultaneously, it was observed that particles inside the alveoli either escaped from the inlet of the alveolar duct or stayed in the alveoli, revealing the irreversibility of particle transport in the alveoli. At the earlier acinar generations, particles were inclined to deposit on the distal alveolar wall. The settling rates of particles of different sizes in the alveoli were also compared. This study provides valuable data for understanding particle transport and sedimentation in the alveoli.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Cambridge University Press (CUP)
Date: 25-03-1995
DOI: 10.1017/S0022112095000929
Abstract: The effect of the separation between hot wires in a crossed wire or X-probe on Reynolds stress measurements has been studied analytically and experimentally. Wyn-gaard's (1968) spectral analysis, which assumes isotropic turbulence, has been modified to include the effect of the tangential velocity component and possible asymmetries of the probe. The relaxation of the assumption of isotropy to one of homogeneity allows corrections to be made to Reynolds stress measurements obtained when the separation between the wires is in the spanwise direction. Measurements with two inclined hot wires in the central region of a fully developed turbulent channel flow provide reasonable support for the modified analysis. In the anisotropic wall region, the measurements provide reasonable support for the correction ratios which have been derived by assuming that turbulence is homogeneous in a plane parallel to the wall.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0LC00040J
Abstract: Inoculation of single cells into separate chambers is one of the key requirements in single-cell analysis. Here we report a three-layer microfluidic platform integrated with dual-pneumatic valves for dynamic screening and printing of single cells.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9LC01273G
Abstract: Flow patterns in the alveoli are investigated using an alveolar microchip and stagnation saddle points are revealed experimentally.
Publisher: American Chemical Society (ACS)
Date: 18-11-2006
DOI: 10.1021/AC060949P
Abstract: We present a highly sensitive capillary electrophoresis (CE) assay that combines transient, single-interface on-chip isotachophoresis (ITP) and a laser-induced confocal fluorescence detection setup. We performed experimental parametric studies to show the effects of microscope objective specifications and intensity of excitation laser on optimization of a high-sensitivity on-chip CE detection system. Using the optimized detection system, single-molecule detection of Alexa Fluor 488 was demonstrated, and signal data were validated with autocorrelation analysis. We also demonstrated a separation and detection of 100 aM fluorophores (Alexa Fluor 488 and bodipy) in a fast assay using a high-sensitivity on-chip CE detection system and an ITP/CE protocol with no manual buffer exchange steps. This is, to the knowledge of the authors, the highest electrophoretic separation sensitivity ever reported.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0LC00092B
Abstract: The study of cell elasticity provides new insights into not only cell biology but also disease diagnosis based on cell mechanical state variation.
Publisher: Public Library of Science (PLoS)
Date: 14-02-2014
Publisher: AIP Publishing
Date: 11-2014
DOI: 10.1063/1.4902908
Abstract: Bioluminescence resonance energy transfer (BRET) is a form of Förster resonance energy transfer. BRET has been shown to support lower limits of detection than fluorescence resonance energy transfer (FRET) but, unlike FRET, has not been widely implemented on microfluidic devices for bioanalytical sensing. We recently reported a microscope-based microfluidic system for BRET-based biosensing, using a hybrid, high quantum-efficiency, form of BRET chemistry. This paper reports the first optical fiber-based system for BRET detection on a microfluidic chip, capable of quantifying photon emissions from the low quantum-efficiency BRET2 system. We investigated the effects of varying core diameter and numerical aperture of optical fibers, as well as varying microfluidic channel design and measurement conditions. We optimized the set-up in order to maximize photon counts and minimize the response time. The optimized conditions supported measurement of thrombin activity, with a limit of detection of 20 pM, which is lower than the microscope-based system and more than 20 times lower than concentrations reported to occur in plasma clots.
Publisher: IOP Publishing
Date: 29-08-2023
Abstract: The dynamics of airflow in the pulmonary acini are of broad interest in understanding respiratory diseases and the fate of inhaled particles. This study investigates the three-dimensional (3d) alveolar flows with rhythmic cavity wall motion, using a finite element method based computational fluid dynamics. This study reports the new research findings on the critical points and associated flow patterns. The locations of critical points are found based on the Brouwer degree theory and Broyden’s method. The phase portrait is used to evaluate the flow patterns around the critical points and the stability (repelling/attracting property) of the critical points on the symmetry plane of the alveolus. Based on the Poincare–Bendixson theorem, the closed orbits on the symmetry plane are found which have the capability to alter the spiral direction of the spiral streamlines. In the 3d space, the alveolar flow is symmetric about the geometric symmetry plane of the alveolus. Different types of 3d critical points, including saddle, spiral, and spiral saddle, are revealed. There are only one saddle point and at least one spiral point or spiral saddle in the alveolar flow. Spiral points and spiral saddles are located on the vortex core line and their number is dependent on the Reynolds number and varies with time. The study of critical points and their evolution helps us to understand the mechanism of irreversible transport of particle tracers from a new perspective.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2AY25214G
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0LC01271H
Abstract: Non-uniform radial perturbations due to non-self-similar alveolar expansion drive the closed vortex into a spiral and the change of spiral rotation direction.
Publisher: MDPI AG
Date: 12-02-2021
DOI: 10.3390/MI12020184
Abstract: The transport and deposition of micro/nanoparticles in the lungs under respiration has an important impact on human health. Here, we presented a real-scale alveolar chip with movable alveolar walls based on the microfluidics to experimentally study particle transport in human lung alveoli under rhythmical respiratory. A new method of mixing particles in aqueous solution, instead of air, was proposed for visualization of particle transport in the alveoli. Our novel design can track the particle trajectories under different force conditions for multiple periods. The method proposed in this study gives us better resolution and clearer images without losing any details when mapping the particle velocities. More detailed particle trajectories under multiple forces with different directions in an alveolus are presented. The effects of flow patterns, drag force, gravity and gravity directions are evaluated. By tracing the particle trajectories in the alveoli, we find that the drag force contributes to the reversible motion of particles. However, compared to drag force, the gravity is the decisive factor for particle deposition in the alveoli.
Publisher: SPIE
Date: 21-12-2011
DOI: 10.1117/12.903271
Publisher: IOP Publishing
Date: 10-01-1997
Publisher: American Physical Society (APS)
Date: 09-09-1996
Publisher: Springer Science and Business Media LLC
Date: 2004
Publisher: IOP Publishing
Date: 28-04-2011
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.ULTRAS.2009.10.002
Abstract: Cavitation microstreaming plays a role in the therapeutic action of microbubbles driven by ultrasound, such as the sonoporative and sonothrombolytic phenomena. Microscopic particle-image velocimetry experiments are presented. Results show that many different microstreaming patterns are possible around a microbubble when it is on a surface, albeit for microbubbles much larger than used in clinical practice. Each pattern is associated with a particular oscillation mode of the bubble, and changing between patterns is achieved by changing the sound frequency. Each microstreaming pattern also generates different shear stress and stretch/compression distributions in the vicinity of a bubble on a wall. Analysis of the micro-PIV results also shows that ultrasound-driven microstreaming flows around bubbles are feasible mechanisms for mixing therapeutic agents into the surrounding blood, as well as assisting sonoporative delivery of molecules across cell membranes. Patterns show significant variations around the bubble, suggesting sonoporation may be either enhanced or inhibited in different zones across a cellular surface. Thus, alternating the patterns may result in improved sonoporation and sonothrombolysis. The clear and reproducible delineation of microstreaming patterns based on driving frequency makes frequency-based pattern alternation a feasible alternative to the clinically less desirable practice of increasing sound pressure for equivalent sonoporative or sonothrombolytic effect. Surface ergence is proposed as a measure relevant to sonoporation.
Publisher: IOP Publishing
Date: 22-05-2009
Publisher: Elsevier BV
Date: 10-2016
Publisher: Springer Science and Business Media LLC
Date: 14-05-2010
Publisher: Wiley
Date: 24-01-2014
DOI: 10.1002/APP.40416
Publisher: Future Science Ltd
Date: 10-2009
DOI: 10.2144/000113242
Abstract: Mixing fluids for biochemical assays is problematic when volumes are very small (on the order of the 10 µL typical of single drops), which has inspired the development of many micromixing devices. In this paper, we show that micromixing is possible in the simple open wells of standard laboratory consumables using appropriate acoustic frequencies that can be applied using cheap, conventional audio components. Earlier work has shown that the phenomenon of acoustic microstreaming can mix fluids, provided that bubbles are introduced into a specially designed microchamber or that high-frequency surface acoustic wave devices are constructed. We demonstrate a key simplification: acoustic micromixing at audio frequencies by ensuring the system has a liquid-air interface with a small radius of curvature. The meniscus of a drop in a small well provided an appropriately small radius, and so an introduced bubble was not necessary. Microstreaming showed improvement over diffusion-based mixing by 1–2 orders of magnitude. Furthermore, significant improvements are attainable through the utilization of chaotic mixing principles, whereby alternating fluid flow patterns are created by applying, in sequence, two different acoustic frequencies to a drop of liquid in an open well.
Publisher: AIP Publishing
Date: 05-10-2009
DOI: 10.1063/1.3242019
Abstract: A polydimethylsiloxane microchip consisting of a T-junction microchannel network and a thin glass capillary has been developed for the generation of microbubbles. The glass capillary is used to produce an ultrathin gas jet and to controllably block the straight liquid channel, thereby increasing the local liquid velocity near the intersection. Liquid flow rate, liquid viscosity, gas pressure, and inner diameter of the gas jet are varied to investigate the effect on bubble generation. Bubbles with a diameter down to 4.5 μm can be produced at a high rate of 7.5 kHz using a capillary with an inner diameter of 2 μm.
Publisher: IOP Publishing
Date: 22-07-2015
Publisher: Informa UK Limited
Date: 2001
DOI: 10.1252/JCEJ.34.579
Publisher: IOP Publishing
Date: 04-02-2015
Publisher: Springer Science and Business Media LLC
Date: 10-06-2016
Publisher: MDPI AG
Date: 23-11-2022
DOI: 10.3390/MI13122052
Abstract: Metal foams have been widely used in heat pipes as wicking materials. The main issue with metal foams is the surface property capillary limit. In this paper, a chemical blackening process for creating a superhydrophilic surface on copper foams is studied with seven different NaOH and NaClO2 solution concentrations (1.5~4.5 mol/L), in which the microscopic morphology of the treated copper foam surface is analyzed by scanning electron microscopy. The capillary experiments are carried out to quantify the wicking characteristics of the treated copper foams and the results are compared with theoretical models. A the microscope is used to detect the flow stratification characteristics of the capillary rise process. The results show that the best wicking ability is obtained for the oxidation of copper foam using 3.5 mol/L of NaOH and NaClO2 solution. Gravity plays a major role in defining the permeability and effective pore radius, while the effect of evaporation can be ignored. The formation of a fluid stratified interface between the unsaturated and saturated zone results in capillary performance degradation. The current study is important for understanding the flow transport in porous materials.
Publisher: Wiley
Date: 15-11-2004
DOI: 10.1002/AIC.10232
Publisher: AIP Publishing
Date: 11-1996
DOI: 10.1063/1.869084
Abstract: The previously established similarity between the temperature spectrum and the spectrum corresponding to the mean turbulent energy in a wide variety of turbulent (shear) flows is re-examined within the framework of second-order velocity and temperature structure functions. Measurements in a turbulent wake indicate that Dq, the sum of the three second-order velocity structure functions bears close similarity to Dθ, the second-order temperature structure function, when Dq and Dθ are normalized by the mean turbulent energy and temperature variance, respectively. This similarity also applies to other flows. In the limit of small separations, the Kolmogorov-normalized structure functions differ only by the value of the molecular Prandtl number. In the inertial range, the Obukhov–Corrsin constant differs from the Dq Kolmogorov constant by a factor equal to the dissipation time scale ratio. This ratio is typically about 0.5.
Publisher: Elsevier BV
Date: 02-2017
Publisher: Elsevier BV
Date: 06-2019
Publisher: Springer Science and Business Media LLC
Date: 14-02-2017
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.BIOS.2011.10.043
Abstract: Mercury is a highly toxic metal that can cause significant harm to humans and aquatic ecosystems. This paper describes a novel approach for mercury (Hg(2+)) ion detection by using label-free oligonucleotide probes and Escherichia coli exonuclease I (Exo I) in a microfluidic electrophoretic separated platform. Two single-stranded DNAs (ssDNA) TT-21 and TT-44 with 7 Thymine-Thymine mispairs are employed to capture mercury ions. Due to the coordination structure of T-Hg(2+)-T, these ssDNAs are folded into hairpin-like double-stranded DNAs (dsDNA) which are more difficult to be digested by Exo I, as confirmed by polyacrylamide gel electrophoresis (PAGE) analysis. A series of microfluidic capillary electrophoretic separation studies are carried out to investigate the effect of Exo I and mercury ion concentrations on the detected fluorescence intensity. This method has demonstrated a high sensitivity of mercury ion detection with the limit of detection around 15 nM or 3 ppb. An excellent selectivity of the probe for mercury ions over five interference ions Fe(3+), Cd(2+), Pb(2+), Cu(2+) and Ca(2+) is also revealed. This method could potentially be used for mercury ion detection with high sensitivity and reliability.
Publisher: Wiley
Date: 26-04-2013
Publisher: SPIE
Date: 27-12-2006
DOI: 10.1117/12.695687
Publisher: Wiley
Date: 03-2000
Publisher: SPIE
Date: 27-12-2006
DOI: 10.1117/12.695682
Publisher: MDPI AG
Date: 10-11-2022
DOI: 10.3390/BIOENGINEERING9110674
Abstract: The rapid promotion of single-cell omics in various fields has begun to help solve many problems encountered in research, including precision medicine, prenatal diagnosis, and embryo development. Meanwhile, single-cell techniques are also constantly updated with increasing demand. For some specific target cells, the workflow from droplet screening to single-cell sequencing is a preferred option and should reduce the impact of operation steps, such as demulsification and cell recovery. We developed an all-in-droplet method integrating cell encapsulation, target sorting, droplet picoinjection, and single-cell transcriptome profiling on chips to achieve labor-saving monitoring of TCR-T cells. As a proof of concept, in this research, TCR-T cells were encapsulated, sorted, and performed single-cell transcriptome sequencing (scRNA-seq) by injecting reagents into droplets. It avoided the tedious operation of droplet breakage and re-encapsulation between droplet sorting and scRNA-seq. Moreover, convenient device operation will accelerate the progress of chip marketization. The strategy achieved an excellent recovery performance of single-cell transcriptome with a median gene number over 4000 and a cross-contamination rate of 8.2 ± 2%. Furthermore, this strategy allows us to develop a device with high integrability to monitor infused TCR-T cells, which will promote the development of adoptive T cell immunotherapy and their clinical application.
Publisher: Springer Science and Business Media LLC
Date: 11-06-2016
DOI: 10.1007/S10544-016-0078-7
Abstract: Focusing and ordering of micro- or nanoparticles is an essential ability in microfluidic platforms for bio-s le processing. Hydrophoresis is an effective method utilising hydrodynamic force to focus microparticles, but it is limited by the fixed operational range and the lack of flexibility. Here, we report a work to tune and improve the dynamic range of hydrophoresis device using magnetophoresis. In this work, a novel approach was presented to fabricate the lateral fluidic ports, which allow the flipped chip to remain stable on the stage of microscope. Diamagnetic polystyrene microparticles suspended in a ferrofluidic medium were repelled to the lower level of the channel by negative magnetophoretic force, and then interact with grooves of microchannel to obtain an excellent hydrophoretic ordering. The effects of (i) flow rate, (ii) particle size, (iii) magnetic susceptibility of the medium, and (iv) number of magnets on the particle focusing efficiency were also reported. As the proposed magnetophorsis-assisted hydrophoretic device is tuneable and simple, it holds great potential to be integrated with other microfluidic components to form an integrated s le-to-answer system.
Publisher: Wiley
Date: 20-07-2022
Abstract: The detection of cancer biomarkers is of great significance for the early screening of cancer. Detecting the content of sarcosine in blood or urine has been considered to provide a basis for the diagnosis of prostate cancer. However, it still lacks simple, high‐precision and wide‐ranging sarcosine detection methods. In this work, a Ti 3 C 2 T X /Pt–Pd nanocomposite with high stability and excellent electrochemical performance has been synthesized by a facile one‐step alcohol reduction and then used on a glassy carbon electrode (GCE) with sarcosine oxidase (SO x ) to form a sarcosine biosensor (GCE/Ti 3 C 2 T X /Pt–Pd/SO x ). The prominent electrocatalytic activity and biocompatibility of Ti 3 C 2 T X /Pt–Pd enable the SO x to be highly active and sensitive to sarcosine. Under the optimized conditions, the prepared biosensor has a wide linear detection range to sarcosine from 1 to 1000 µM with a low limit of detection of 0.16 µM (S/N = 3) and a sensitivity of 84.1 µA/mM cm 2 . Besides, the reliable response in serum s les shows its potential in the early diagnosis of prostate cancer. More importantly, the successful construction and application of the erometric biosensor based on Ti 3 C 2 T X /Pt–Pd will provide a meaningful reference for detecting other cancer biomarkers.
Publisher: Springer Science and Business Media LLC
Date: 13-03-2020
DOI: 10.1038/S41535-020-0220-X
Abstract: We investigate the circuit quantum electrodynamics of anharmonic superconducting nanowire oscillators. The s le circuit consists of a capacitively shunted nanowire with a width of about 20 nm and a varying length up to 350 nm, capacitively coupled to an on-chip resonator. By applying microwave pulses we observe Rabi oscillations, measure coherence times and the anharmonicity of the circuit. Despite the very compact design, simple top-down fabrication and high degree of disorder in the oxidized (granular) aluminum material used, we observe lifetimes in the microsecond range.
Publisher: MDPI AG
Date: 08-06-2021
DOI: 10.3390/MA14123153
Abstract: Due to their high porosity, high stiffness, light weight, large surface area-to-volume ratio, and excellent thermal properties, open-cell metal foams have been applied in a wide range of sectors and industries, including the energy, transportation, aviation, biomedical, and defense industries. Understanding the flow characteristics and pressure drop of the fluid flow in open-cell metal foams is critical for applying such materials in these scenarios. However, the state-of-the-art pressure drop correlations for open-cell foams show large deviations from experimental data. In this paper, the fundamental governing equations of fluid flow through open-cell metal foams and the determination of different foam geometry structures are first presented. A variety of published models for predicting the pressure drop through open-cell metal foams are then summarized and validated against experimental data. Finally, two empirical correlations of permeability are developed and recommended based on the model of Calmidi. Moreover, Calmidi’s model is proposed to calculate the Forchheimer coefficient. These three equations together allow calculating the pressure drop through open-cell metal foam as a function of porosity and pore diameter (or strut diameter) in a wide range of porosities ε = 85.7–97.8% and pore densities of 10–100 PPI. The findings of this study greatly advance our understanding of the flow characteristics through open-cell metal foam and provide important guidance for the design of open-cell metal foam materials for different engineering applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1LC00638J
Abstract: This paper reports the numerical, mathematical, and experimental studies of flow delay through wax valves surrounded by PDMS walls on paper microfluidics.
Publisher: Elsevier BV
Date: 07-2016
Publisher: AIP Publishing
Date: 07-1995
DOI: 10.1063/1.868482
Abstract: The refined similarity hypothesis of Kolmogorov [J. Fluid Mech. 13, 82 (1962)] is extended to a scalar field. These hypotheses are tested using measurements in a circular jet and the atmospheric surface layer. Over a significant part of the inertial range, statistics of the normalized stochastic variables for velocity and temperature indicate a dependence on the separation r. This dependence is also quantified through the probability density functions of the stochastic variables and the correlation between the velocity (or temperature) increment and the local energy (or temperature) dissipation rates. Probability density functions of the stochastic variables are conditioned on the local Reynolds number Rer based on r and the local energy dissipation rate. These functions depend on Rer when the latter is small and are approximately universal when Rer is very large. This behaviour is consistent with the refined similarity hypothesis. There is however a slight difference between the shapes of the conditional probability density functions in the two flows, implying a weak dependence on the turbulence Reynolds number Rλ and flow conditions.
Publisher: Informa UK Limited
Date: 2007
DOI: 10.1252/JCEJ.40.213
Publisher: Elsevier BV
Date: 08-2019
Publisher: Springer Science and Business Media LLC
Date: 11-11-2017
Publisher: Elsevier BV
Date: 07-1997
Publisher: Elsevier BV
Date: 2010
Publisher: ACM
Date: 17-06-2014
Publisher: IOP Publishing
Date: 10-1996
Publisher: AIP Publishing
Date: 11-2014
DOI: 10.1063/1.4903761
Abstract: Microfluidic diagnostic devices often require handling particles or cells with different sizes. In this investigation, a tunable hydrophoretic device was developed which consists of a polydimethylsiloxane (PDMS) slab with hydrophoretic channel, a PDMS diaphragm with pressure channel, and a glass slide. The height of the hydrophoretic channel can be tuned simply and reliably by deforming the elastomeric diaphragm with pressure applied on the pressure channel. This operation allows the device to have a large operating range where different particles and complex biological s les can be processed. The focusing performance of this device was tested using blood cells that varied in shape and size. The hydrophoretic channel had a large cross section which enabled a throughput capability for cell focusing of ∼15 000 cells s−1, which was more than the conventional hydrophoretic focusing and dielectrophoresis (DEP)-active hydrophoretic methods. This tunable hydrophoretic focuser can potentially be integrated into advanced lab-on-a-chip bioanalysis devices.
Publisher: SPIE
Date: 26-12-2008
DOI: 10.1117/12.813449
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.ACA.2016.09.023
Abstract: A simple, fast and low-cost method for dopamine (DA) detection based on turn-on fluorescence using resorcinol is developed. The rapid reaction between resorcinol and DA allows the detection to be performed within 5 min, and the reaction product (azamonardine) with high quantum yield generates strong fluorescence signal for sensitive optical detection. The detection exhibits a high sensitivity to DA with a wide linear range of 10 nM-20 μM and the limit of detection is estimated to be 1.8 nM (S/N = 3). This approach has been successfully applied to determine DA concentrations in human urine s les with satisfactory quantitative recovery of 97.84%-103.50%, which shows great potential in clinical diagnosis.
Publisher: Wiley
Date: 04-2011
Publisher: Elsevier BV
Date: 12-2014
DOI: 10.1016/J.BIOS.2014.06.032
Abstract: We have previously shown that a genetically encoded bioluminescent resonance energy transfer (BRET) biosensor, comprising maltose binding protein (MBP) flanked by a green fluorescent protein (GFP(2)) at the N-terminus and a variant of Renilla luciferase (RLuc2) at the C-terminus, has superior sensitivity and limits of detection for maltose, compared with an equivalent fluorescent resonance energy transfer (FRET) biosensor. Here, we demonstrate that the same MBP biosensor can be combined with a microfluidic system for detection of maltose in water or beer. Using the BRET-based biosensor, maltose in water was detected on a microfluidic chip, either following a pre-incubation step or in real-time with similar sensitivity and dynamic range to those obtained using a commercial 96-well plate luminometer. The half-maximal effective concentrations (EC50) were 2.4×10(-7)M and 1.3×10(-7) M for maltose detected in pre-incubated and real-time reactions, respectively. To demonstrate real-time detection of maltose in a complex medium, we used it to estimate maltose concentration in a commercial beer s le in a real-time, continuous flow format. Our system demonstrates a promising approach to in-line monitoring for applications such as food and beverage processing.
Publisher: American Chemical Society (ACS)
Date: 15-08-2023
Publisher: Springer Science and Business Media LLC
Date: 26-04-2016
DOI: 10.1038/SREP24972
Abstract: Solar photovoltaics (PV) are emerging as a major alternative energy source. The cost of PV electricity depends on the efficiency of conversion of light to electricity. Despite of steady growth in the efficiency for several decades, little has been achieved to reduce the impact of real-world operating temperatures on this efficiency. Here we demonstrate a highly efficient cooling solution to the recently emerging high performance plasmonic solar cell technology by integrating an advanced nano-coated heat-pipe plate. This thermal cooling technology, efficient for both summer and winter time, demonstrates the heat transportation capability up to ten times higher than those of the metal plate and the conventional wickless heat-pipe plates. The reduction in temperature rise of the plasmonic solar cells operating under one sun condition can be as high as 46%, leading to an approximate 56% recovery in efficiency, which dramatically increases the energy yield of the plasmonic solar cells. This newly-developed, thermally-managed plasmonic solar cell device significantly extends the application scope of PV for highly efficient solar energy conversion.
Publisher: American Chemical Society (ACS)
Date: 07-12-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C2TC00241H
Publisher: Springer Science and Business Media LLC
Date: 24-07-2015
Publisher: IOP Publishing
Date: 05-1995
Publisher: Elsevier BV
Date: 07-2000
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B924271F
Abstract: This review focuses on the use of Förster Resonance Energy Transfer (FRET) to monitor intra- and intermolecular reactions occurring in microfluidic reactors. Microfluidic devices have recently been used for performing highly efficient and miniaturised biological assays for the analysis of biological entities such as cells, proteins and nucleic acids. Microfluidic assays are characterised by nanolitre to femtolitre reaction volumes, which necessitates the adoption of a sensitive optical detection scheme. FRET serves as a strong 'spectroscopic ruler' for elucidating the tertiary structure of biomolecules, as the efficiency of the non-radiative energy transfer is extremely sensitive to nanoscale changes in the separation between donor and acceptor markers attached to the biomolecule of interest. In this review, we will review the implementation of various microfluidic assays which employ FRET for erse applications in the biomedical field, along with the advantages and disadvantages of the various approaches. The future prospects for development of microfluidic devices incorporating FRET detection will be discussed.
Publisher: AIP Publishing
Date: 30-10-2017
DOI: 10.1063/1.4995657
Abstract: We have developed a microfluidic needle-like device that can extract and deliver nanoliter s les. The device consists of a T-junction to form segmented flows, parallel channels to and from the needle tip, and seven hydrophilic capillaries at the tip that form a phase-extraction region. The main microchannel is hydrophobic and carries segmented flows of water-in-oil. The hydrophilic capillaries transport the aqueous phase with a nearly zero pressure gradient but require a pressure gradient of 19 kPa for mineral oil to invade and flow through. Using this device, we demonstrate the delivery of nanoliter droplets and demonstrate s ling through the formation of droplets at the tip of our device. During s ling, we recorded the fluorescence intensities of the droplets formed at the tip while varying the concentration of dye outside the tip. We measured a chemical signal response time of approximately 3 s. The linear relationship between the recorded fluorescence intensity of s les and the external dye concentration (10–40 μg/ml) indicates that this device is capable of performing quantitative, real-time measurements of rapidly varying chemical signals.
Publisher: SPIE
Date: 26-12-2008
DOI: 10.1117/12.810684
Publisher: SPIE
Date: 28-12-2005
DOI: 10.1117/12.668030
Publisher: Springer Science and Business Media LLC
Date: 11-07-2015
DOI: 10.1007/S10544-015-9987-0
Abstract: Sound wave-assisted acoustic micromixing has been shown to increase the binding of molecules in small volumes (10-100 μL) where effective mixing is difficult to achieve through conventional techniques. The aim of this work is to study whether acoustic micromixing can increase the binding efficiency of antibodies to their antigens, a reaction that forms the basis of immunoassays, including enzyme-linked immunosorbent assay (ELISA). Using a procedure from a general ELISA and immobilizing an antigen on wells of 96-well plates, it was found that acoustic micromixing at 125-150 Hz increased the initial rate of antibody-antigen binding by over 80 % and the total binding at the end point (i.e., 45 min) by over 50 %. As a result, acoustic micromixing achieved a binding level in 9 min that would otherwise take 45 min on a standard platform rocking mixer. Therefore acoustic micromixing has the potential to increase the detection sensitivity of ELISA as well as shorten the antigen-antibody binding times from typically 45-60 min to 15 min.
Publisher: Elsevier BV
Date: 2016
Publisher: Springer Science and Business Media LLC
Date: 11-05-1998
Publisher: SPIE
Date: 07-12-2013
DOI: 10.1117/12.2033508
Publisher: Wiley
Date: 2000
DOI: 10.1002/1099-1565(200011/12)11:6<362::AID-PCA542>3.0.CO;2-U
Publisher: Springer Science and Business Media LLC
Date: 02-06-1999
Publisher: MDPI AG
Date: 30-03-2023
DOI: 10.3390/MI14040770
Abstract: Cell metabolite detection is important for cell analysis. As a cellular metabolite, lactate and its detection play an important role in disease diagnosis, drug screening and clinical therapeutics. This paper reports a microfluidic chip integrated with a backflow prevention channel for cell culture and lactate detection. It can effectively realize the upstream and downstream separation of the culture chamber and the detection zone, and prevent the pollution of cells caused by the potential backflow of reagent and buffer solutions. Due to such a separation, it is possible to analyze the lactate concentration in the flow process without contamination of cells. With the information of residence time distribution of the microchannel networks and the detected time signal in the detection chamber, it is possible to calculate the lactate concentration as a function of time using the de-convolution method. We have further demonstrated the suitability of this detection method by measuring lactate production in human umbilical vein endothelial cells (HUVEC). The microfluidic chip presented here shows good stability in metabolite quick detection and can work continuously for more than a few days. It sheds new insights into pollution-free and high-sensitivity cell metabolism detection, showing broad application prospects in cell analysis, drug screening and disease diagnosis.
Publisher: American Physical Society (APS)
Date: 25-02-2021
Publisher: AIP Publishing
Date: 03-1996
DOI: 10.1063/1.868865
Abstract: Direct numerical simulation data for two-point velocity and vorticity correlations at small separations near the centerline of a fully developed turbulent channel flow are more closely approximated by axisymmetry than isotropy.
Publisher: Elsevier BV
Date: 05-2023
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/CH10116
Abstract: Increasingly over the past two decades, biotechnologists have been exploiting various molecular technologies for high-throughput screening of genes and their protein products to isolate novel functionalities with a wide range of industrial applications. One particular technology now widely used for these purposes involves directed evolution, an artificial form of evolution in which genes and proteins are evolved towards new or improved functions by imposing intense selection pressures on libraries of mutant genes generated by molecular biology techniques and expressed in heterologous systems such as Escherichia coli. Most recently, the rapid development of droplet-based microfluidics has created the potential to dramatically increase the power of directed evolution by increasing the size of the libraries and the throughput of the screening by several orders of magnitude. Here, we review the methods for generating and controlling droplets in microfluidic systems, and their applications in directed evolution. We focus on the methodologies for cell-based assays, in vitro protein expression and DNA lification, and the prospects for using such platforms for directed evolution in next-generation biotechnologies.
Publisher: Royal Society of Chemistry (RSC)
Date: 18-06-2014
DOI: 10.1039/C4LC00343H
Abstract: Plasma is a complex substance that contains proteins and circulating nucleic acids and viruses that can be utilised for clinical diagnostics, albeit a precise analysis depends on the plasma being totally free of cells. We proposed the use of a dielectrophoresis (DEP)-active hydrophoretic method to isolate plasma from blood in a high-throughput manner. This microfluidic device consists of anisotropic microstructures embedded on the top of the channel which generate lateral pressure gradients while interdigitised electrodes lay on the bottom of the channel which can push particles or cells into a higher level using a negative DEP force. Large and small particles or cells (3 μm and 10 μm particles, and red blood cells, white blood cells, and platelets) can be focused at the same time in our DEP-active hydrophoretic device at an appropriate flow rate and applied voltage. Based on this principle, all the blood cells were filtrated from whole blood and then the plasma was extracted with a purity of 94.2% and a yield of 16.5% at a flow rate of 10 μL min(-1). This solved the challenging problem caused by the relatively low throughput of the DEP based device. Our DEP-active hydrophoretic device is a flexible and tunable system that can control the lateral positions of particles by modulating the external voltages without redesigning and fabricating a new channel, and because it is easy to operate, it is easily compatible with other microfluidic platforms that are used for further detection.
Publisher: Wiley
Date: 06-2002
Publisher: Springer Science and Business Media LLC
Date: 19-11-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR06367B
Abstract: The integration of acoustic micromixing and single bead trapping enables the identification of fluorescent signals from multiple biomarkers within minutes.
Publisher: Cambridge University Press (CUP)
Date: 10-11-1998
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6LC01263A
Abstract: An integrated device with nanoparticle assay and chaotic micromixing for rapid detection of Hendra virus antibodies.
Publisher: Elsevier BV
Date: 11-2001
Publisher: Elsevier BV
Date: 11-2006
Publisher: Wiley
Date: 11-2008
Abstract: Contactless conductivity detector technology has unique advantages for microfluidic applications. However, the low S/N and varying baseline makes the signal analysis difficult. In this paper, a continuous wavelet transform-based peak detection algorithm was developed for CE signals from microfluidic chips. The Ridger peak detection algorithm is based on the MassSpecWavelet algorithm by Du et al. [Bioinformatics 2006, 22, 2059-2065], and performs a continuous wavelet transform on data, using a wavelet proportional to the first derivative of a Gaussian function. It forms sequences of local maxima and minima in the continuous wavelet transform, before pairing sequences of maxima to minima to define peaks. The peak detection algorithm was tested against the Cromwell, MassSpecWavelet, and Linear Matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometer Peak Indication and Classification algorithms using experimental data. Its sensitivity to false discovery rate curve is superior to other techniques tested.
Publisher: AIP Publishing
Date: 08-1996
DOI: 10.1063/1.868998
Abstract: Autocorrelations of squared velocity derivatives and squared vorticity fluctuation components have been measured at the centerline in the wake of a circular cylinder. Near the start of the inertial range, all the correlations exhibit similar power-law behaviors and yield essentially the same estimate of the intermittency exponent μ. The results imply that (∂u/∂x)2 may be a reasonable substitute for the instantaneous dissipation rate of turbulent kinetic energy, for determining the value of μ.
Publisher: IOP Publishing
Date: 03-1997
Publisher: IOP Publishing
Date: 10-1996
Publisher: Hindawi Limited
Date: 2014
DOI: 10.1155/2014/175457
Abstract: A microchip pressure-driven liquid chromatographic system with a packed column has been designed and fabricated by using poly(dimethylsiloxane) (PDMS). The liquid chromatographic column was packed with mesoporous silica beads of Ia3d space group. Separation of dyes and biopolymers was carried out to verify the performance of the chip. A mixture of dyes (fluorescein and rhodamine B) and a biopolymer mixture (10 kDa Dextran and 66 kDa BSA) were separated and the fluorescence technique was employed to detect the movement of the molecules. Fluorescein molecule was a nonretained species and rhodamine B was attached onto silica surface when dye mixture in deionized water was injected into the microchannel. The retention times for dextran molecule and BSA molecule in biopolymer separation experiment were 45 s and 120 s, respectively. Retention factor was estimated to be 3.3 for dextran and 10.4 for BSA. The selectivity was 3.2 and resolution was 10.7. Good separation of dyes and biopolymers was achieved and the chip design was verified.
Publisher: SPIE
Date: 28-12-2005
DOI: 10.1117/12.660970
Publisher: SPIE
Date: 26-12-2008
DOI: 10.1117/12.810863
Publisher: AIP Publishing
Date: 08-1996
DOI: 10.1063/1.868992
Abstract: The vorticity spectrum has been inferred, using local isotropy, from measurements of the lateral vorticity components in a turbulent wake over a small Reynolds number range. The high wavenumber part of the spectrum supports Kolmogorov’s [C. R. Akad. Sci. USSR 30, 301 (1941)] similarity theory. Among the different published analytical expressions for the three-dimensional energy spectrum, the model of Kida and Murakami [Phys. Fluids 30, 2030 (1987)] is closest to the present data.
Publisher: SPIE
Date: 28-12-2005
DOI: 10.1117/12.660972
Publisher: Wiley
Date: 18-12-2014
Abstract: This work explores dielectrophoresis (DEP)-active hydrophoresis in sorting particles and cells. The device consists of prefocusing region and sorting region with great potential to be integrated into advanced lab-on-a-chip bioanalysis devices. Particles or cells can be focused in the prefocusing region and then sorted in the sorting region. The DEP-active hydrophoretic sorting is not only based on size but also on dielectric properties of the particles or cells of interest without any labelling. A mixture of 3 and 10 μm particles were sorted and collected from corresponding outlets with high separation efficiency. According to the different dielectric properties of viable and nonviable Chinese Hamster Ovary (CHO) cells at the medium conductivity of 0.03 S/m, the viable CHO cells were focused well and sorted from cell s le with a high purity.
Publisher: American Physical Society (APS)
Date: 05-1998
Publisher: Elsevier BV
Date: 05-2016
Publisher: SPIE
Date: 07-12-2013
DOI: 10.1117/12.2033569
Publisher: Informa UK Limited
Date: 13-04-2014
Publisher: Cambridge University Press (CUP)
Date: 10-02-2000
DOI: 10.1017/S0022112099007090
Abstract: The process by which a liquid jet falling into a liquid pool entrains air is studied experimentally and theoretically. It is shown that, provided the nozzle from which the jet issues is properly contoured, an undisturbed jet does not entrap air even at relatively high Reynolds numbers. When surface disturbances are generated on the jet by a rapid increase of the liquid flow rate, on the other hand, large air cavities are formed. Their collapse under the action of gravity causes the entrapment of bubbles in the liquid. This sequence of events is recorded with a CCD and a high-speed camera. A boundary-integral method is used to simulate the process numerically with results in good agreement with the observations. An unexpected finding is that the role of the jet is not simply that of conveying the disturbance to the pool surface. Rather, both the observed energy budget and the simulations imply the presence of a mechanism by which part of the jet energy is used in creating the cavity. A hypothesis on the nature of this mechanism is presented.
Publisher: Elsevier BV
Date: 09-2015
DOI: 10.1016/J.JVIROMET.2015.05.008
Abstract: Detection of Hendra viral IgG antibody in animal sera is useful for surveillance following a virus outbreak. The commonly used enzyme-linked immunosorbent assay and fluorescence-based Luminex assay typically consist of three steps and take at least several hours to complete. We have simplified the procedure to two steps in an effort to develop a rapid procedure for IgG antibody, but not IgM antibody, detection. This is achieved by conjugating the fluorescence label R-phycoerythrin directly onto the IgG binding protein Protein G. The use of magnetic nanoparticles, due to their large specific surface area, has helped reduce each of the binding steps to 20 min. As a result, the whole assay can be completed in 60 min. We also demonstrate a method to quickly estimate IgG antibody titres by assaying the sera at only two dilutions (i.e. 1:20 and 1:1000) and using the fluorescence ratio at these dilutions as an indicator of antibody titre. The results of this approach correlated well with the well-regarded serum neutralization test in virus antibody assays. This protocol reported here can be adopted in Luminex assays, fluorescence-linked immunosorbent assays and assays on microfluidics platforms for rapid antibody surveillance of Hendra and other viruses.
Publisher: Elsevier BV
Date: 2018
Publisher: American Chemical Society (ACS)
Date: 14-03-2019
DOI: 10.1021/ACS.ANALCHEM.8B05764
Abstract: Microfluidic paper-based analytical devices (μPADs) have been extensively studied for disease diagnostics, food quality control, and environmental monitoring due to the advantages of low cost, portability, and simplicity. The lack of flow controllability has triggered the development of valves for such devices. This paper reports the μPADs integrating novel wax valves for distance-based detection. The valves are printed on paper and can be manually opened by organic solvents within seconds. The opened valve does not influence the flow. The μPADs with wax valves were then applied in the distance-based detection of potassium iodate and glucose. The valves allow mixing of reagents and subsequent incubation in the loading zone, resulting in a shorter detection time and larger linear detection range. This study has demonstrated a linear detection range of 0.05-0.5 mM for potassium iodate, while linear ranges of 1-5 and 2.5-80 mg/dL are achieved for glucose when total detection time is 15 and 25 min, respectively. The lower detection limit is only 1/11 of that in a previous study. The detection ranges of iodate and glucose assays cover the concentrations of iodate in salt/milk and glucose in human saliva, respectively. Due to the simplicity, reliability, and ability for high-density integration, the μPADs with wax valves are of great potential in point-of-care (s ling) applications.
Publisher: MDPI AG
Date: 30-11-2022
DOI: 10.3390/BIOS12121100
Abstract: Separation and clonal culture and growth kinetics analysis of target cells in a mixed population is critical for pathological research, disease diagnosis, and cell therapy. However, long-term culture with time-lapse imaging of the isolated cells for clonal analysis is still challenging. This paper reports a microfluidic device with four-level filtration channels and a pneumatic microvalve for size sorting and in situ clonal culture of single cells. The valve was on top of the filtration channels and used to direct fluid flow by membrane deformation during separation and long-term culture to avoid shear-induced cell deformation. Numerical simulations were performed to evaluate the influence of device parameters affecting the pressure drop across the filtration channels. Then, a droplet model was employed to evaluate the impact of cell viscosity, cell size, and channel width on the pressure drop inducing cell deformation. Experiments showed that filtration channels with a width of 7, 10, 13, or 17 μm successfully sorted K562 cells into four different size ranges at low driving pressure. The maximum efficiency of separating K562 cells from media and whole blood was 98.6% and 89.7%, respectively. Finally, the trapped single cells were cultured in situ for 4–7 days with time-lapse imaging to obtain the lineage trees and growth curves. Then, the time to the first ision, variation of cell size before and after ision, and cell fusion were investigated. This proved that cells at the G1 and G2 phases were of significantly distinct sizes. The microfluidic device for size sorting and clonal expansion will be of tremendous application potential in single-cell studies.
Publisher: Springer Science and Business Media LLC
Date: 09-08-2020
No related grants have been discovered for Yonggang Zhu.