ORCID Profile
0000-0002-8861-2161
Current Organisations
SA Node of the Australian National Fabrication Facility
,
University of South Australia
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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)
Nanofabrication, Growth and Self Assembly | Colloid and Surface Chemistry | Nanotechnology | Analytical Chemistry | Biomedical Instrumentation | Instrumental Methods (excl. Immunological and Bioassay Methods) | Biomaterials | Electroanalytical Chemistry | Biomedical Engineering | Nanotoxicology, Health and Safety | Analytical Chemistry not elsewhere classified | Medical Biotechnology | Glass | Vertebrate Biology | Materials Engineering | Composite and Hybrid Materials | Medical Biotechnology Diagnostics (incl. Biosensors) | Photonics, Optoelectronics and Optical Communications
ANZSRC Socio-Economic Objective (SEO)
Diagnostic Methods | Expanding Knowledge in the Chemical Sciences | Skeletal System and Disorders (incl. Arthritis) | Metals (composites, coatings, bonding, etc.) | Primary Mining and Extraction of Mineral Resources not elsewhere classified | Diagnostic methods | Scientific instrumentation | Expanding Knowledge in Technology | Biofuel (Biomass) Energy | Veterinary Diagnostics | Structural Glass and Glass Products | Expanding Knowledge in the Physical Sciences | Scientific Instruments | Expanding Knowledge in Engineering |
Related Links
Publications
In situ formation, manipulation, and imaging of droplet-encapsulated fibrin networks
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B820511F
Abstract: The protein fibrin plays a principal role in blood clotting and forms robust three dimensional networks. Here, microfluidic devices have been tailored to strategically generate and study these bionetworks by confinement in nanoliter volumes. The required protein components are initially encapsulated in separate droplets, which are subsequently merged by electrocoalescence. Next, distinct droplet microenvironments are created as the merged droplets experience one of two conditions: either they traverse a microfluidic pathway continuously, or they "park" to fully evolve an isotropic network before experiencing controlled deformations. High resolution fluorescence microscopy is used to image the fibrin networks in the microchannels. Aggregation (i.e."clotting") is significantly affected by the complicated flow fields in moving droplets. In stopped-flow conditions, an isotropic droplet-spanning network forms after a suitable ripening time. Subsequent network deformation, induced by the geometric structure of the microfluidic channel, is found to be elastic at low rates of deformation. A shape transition is identified for droplets experiencing rates of deformation higher than an identified threshold value. In this condition, significant densification of protein within the droplet due to hydrodynamic forces is observed. These results demonstrate that flow fields considerably affect fibrin in different circumstances exquisitely controlled using microfluidic tools.
Novel Approach to the Formation of Smooth Gold Surfaces
Publisher: American Chemical Society (ACS)
Date: 09-02-2002
DOI: 10.1021/LA011379L
Plasma deposited polyoxazoline thin films for the biofunctionalization of electrochemical sensors
Publisher: Wiley
Date: 09-06-2021
Abstract: Electrochemical immunosensors are an emerging technology for the fast, sensitive, and reliable diagnosis of diseases from bodily fluids. These sensors work by detecting a change in current upon analyte binding to an immuno‐functionalized electrode. Current methods of electrode functionalization are lengthy processes involving self‐assembled monolayer formation and wet chemistry biofunctionalization. Herein, thin films deposited from the plasma phase of oxazoline precursors are investigated and optimized as an alternative approach for electrode functionalization. The plasma‐enabled method has the advantage of being substrate independent and allows the spontaneous binding of biomolecules in physiological buffer. Surface sensitive analysis techniques are employed to characterize the thickness, reactivity, and stability of the thin films before investigating their electrochemical properties on indium tin oxide and gold electrodes including the feasibility to reduce charge transfer resistance with gold nanoparticles. Last, these films are employed to develop an immunosensor for the detection of free epithelial cell adhesion molecule with a limit of detection of 8.7 ng mL −1 .
PCR-assisted impedimetric biosensor for colibactin-encoding pks genomic island detection in E. coli samples
Publisher: Springer Science and Business Media LLC
Date: 27-05-2021
Analysis of co-flowing immiscible liquid streams and their interfaces in a high-throughput solvent extraction chip
Publisher: Springer Science and Business Media LLC
Date: 20-02-2020
Integration of microplasma and microfluidic technologies for localised microchannel surface modification
Publisher: SPIE
Date: 21-12-2011
DOI: 10.1117/12.903293
Dynamics of capillary-driven liquid-liquid displacement in open microchannels
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CP03910F
Abstract: For capillary-driven liquid–liquid displacement in rectangular open microchannels, the square of the position of the liquid–liquid front increases linearly with time, whereas the flow velocity decreases with increasing channel width.
Dynamics of Capillary-Driven Flow in Open Microchannels
Publisher: American Chemical Society (ACS)
Date: 07-09-2011
DOI: 10.1021/JP2065826
Impedance nanopore biosensor: influence of pore dimensions on biosensing performance
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3AN01933K
Uptake of phosphorus from surfactant solutions by wheat leaves: Spreading kinetics, wetted area, and drying time
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5SM01380A
Fast vapor detection by a micropillar array-integrated colorimetric sensor
Publisher: IEEE
Date: 30-10-2022
Surface protein gradients generated in sealed microchannels using spatially varying helium microplasma
Publisher: AIP Publishing
Date: 2015
DOI: 10.1063/1.4913367
Abstract: Spatially varied surface treatment of a fluorescently labeled Bovine Serum Albumin (BSA) protein, on the walls of a closed (sealed) microchannel is achieved via a well-defined gradient in plasma intensity. The microchips comprised a microchannel positioned in-between two microelectrodes (embedded in the chip) with a variable electrode separation along the length of the channel. The channel and electrodes were 50 μm and 100 μm wide, respectively, 50 μm deep, and adjacent to the channel for a length of 18 mm. The electrode separation distance was varied linearly from 50 μm at one end of the channel to a maximum distance of 150, 300, 500, or 1000 μm to generate a gradient in helium plasma intensity. Plasma ignition was achieved at a helium flow rate of 2.5 ml/min, 8.5 kVpk-pk, and 10 kHz. It is shown that the plasma intensity decreases with increasing electrode separation and is directly related to the residual amount of BSA left after the treatment. The plasma intensity and surface protein gradient, for the different electrode gradients studied, collapse onto master curves when plotted against electrode separation. This precise spatial control is expected to enable the surface protein gradient to be tuned for a range of applications, including high-throughput screening and cell-biomolecule-biomaterial interactions.
Patterning of wettability for controlling capillary-driven flow in closed channels
Publisher: Elsevier BV
Date: 07-2013
DOI: 10.1016/J.JCIS.2013.03.058
Abstract: Glass capillaries are prepared with well-defined regions of tuneable wettability on the interior walls using an inexpensive and simple approach. A homogeneous layer of hydrophilic TiO2 nanoparticles is adsorbed on the capillary wall and chemically hydrophobized using octadecyltrihydrosilane (OTHS). The hydrophobic OTHS monolayer is then patterned by spatially-selective removal of the OTHS via TiO2-catalysed decomposition by ultraviolet irradiation. By patterning the capillaries with hydrophilic-hydrophobic rings, modulated penetration of a liquid (glycerol, in this study) can be achieved. For given wettability contrast, the penetration dynamics and equilibrium rise heights are very sensitive to the characteristic length-scale of the pattern, and may offer greater, time-dependent s ling control in fluidic devices.
Microfluidic process intensification for synthesis and formulation in the pharmaceutical industry
Publisher: Elsevier BV
Date: 08-2019
Directed Growth of Orthorhombic Crystals in a Micropillar Array
Publisher: American Chemical Society (ACS)
Date: 02-2017
Characterization of impedance biosensing performance of single and nanopore arrays of anodic porous alumina fabricated by focused ion beam (FIB) milling
Publisher: Elsevier BV
Date: 09-2014
Influence of Water on the Interfacial Nanostructure and Wetting of [Rmim][NTf2] Ionic Liquids at Mica Surfaces
Publisher: American Chemical Society (ACS)
Date: 23-08-2016
Microfluidic solvent extraction of rare earth elements from a mixed oxide concentrate leach solution using Cyanex® 572
Publisher: Elsevier BV
Date: 07-2016
Capillary rise dynamics of aqueous glycerol solutions in glass capillaries: a critical examination of the Washburn equation
Publisher: Elsevier BV
Date: 12-2013
DOI: 10.1016/J.JCIS.2013.05.077
Abstract: The classic description of capillary rise given by the Washburn equation was recently questioned in the light of experimental evidence for a velocity dependent dynamic contact angle at a moving contact line. We present a systematic investigation of the capillary rise dynamics of glycerol and aqueous glycerol solutions in vertical glass capillaries of various radii. For pure glycerol, the results of our experiments are in almost perfect agreement with the predictions of the Washburn equation using independently measured values for the liquid and capillary parameters. For aqueous glycerol solutions we observe discrepancies between the theoretical expectations and the experimental results, which are increasing with the water content of the solution. A thorough analysis, combined with scaling arguments, allows us to conclude that dynamic contact angle effects alone cannot provide a consistent explanation for these discrepancies. Rather, they can be perfectly accounted for if the mixture flowing in the capillary would have an effective, increased viscosity (in respect to the nominal value). We suggest and briefly discuss various mechanisms that could contribute to this observed behavior.
Design considerations for graded index fiber tip Fabry-Perot interferometers
Publisher: IOP Publishing
Date: 12-03-2021
Abstract: An analysis is provided of fiber-optic Fabry–Perot interferometers designed and fabricated using collimating graded-index fiber (GIF) tips as an alternative to typical highly ergent standard single-mode fibers (SMFs). The collimated beam from the GIF tips allows for significantly longer etalons to be fabricated due to the increased collection efficiency when used either in reflection or transmission mode. We extend previous results, showing that GIF tips using coreless fiber segments can allow for up to four-fold increase in fringe visibility (FV) at 1550 nm compared with standard SMF Fabry–Perot etalons of the same length. The collimating GIF tips help lessen the FV vs cavity length trade-off typically observed in fiber-optic Fabry–Perot systems. We also explore the effects on FV improvement when using capillaries to align the fibres. This paper also provides easily accessible design guidelines and considerations for fabricating GIF based devices at 1550 nm.
Impedance spectroscopy study of nanopore arrays for biosensing applications
Publisher: American Scientific Publishers
Date: 07-2014
Microvolume Screening of Extraction and Phase Behavior in a Liquid–Liquid Microsystem
Publisher: American Chemical Society (ACS)
Date: 30-04-2020
Formation and stability of nanoparticle-stabilised oil-in-water emulsions in a microfluidic chip
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.JCIS.2011.07.060
Abstract: The formation and stability of drops in the presence of nanoparticles was studied in a microfluidic device to directly observe the early stages of Pickering emulsification (low interfacial coverage). We observed several key differences between oil droplet necking and rupture in aqueous phases of nanoparticles (methylated silica) and well-characterised surfactant systems. The presence of particles did not influence drop formation dynamics and thus the size of the drops generated. In addition, observations of in-channel drop stability shortly after formation (several milliseconds) indicated that particles in the aqueous phase slow film thinning processes, but do not prevent coalescence. In contrast, downstream collection and densification (at the microchannel outlet), showed that particle-stabilised drops do not coalesce for several weeks, above a critical particle concentration. The implications of our results for droplet microfluidics and our understanding of conventional emulsification systems are discussed.
Structure-induced spreading of liquid in micropillar arrays
Publisher: Springer Science and Business Media LLC
Date: 17-08-2011
Clustering of the Mechanosensitive Ion Channels of Large and Small Conductance MscL and MscS - a FRET-Flim Study
Publisher: Elsevier BV
Date: 2012
On-chip absorption spectroscopy enabled by graded index fiber tips
Publisher: Optica Publishing Group
Date: 08-12-2021
DOI: 10.1364/BOE.414239
Abstract: This paper describes the design and characterization of miniaturized optofluidic devices for sensing based on integrating collimating optical fibers with custom microfluidic chips. The use of collimating graded-index fiber (GIF) tips allows for effective fiber-channel-fiber interfaces to be realized when compared with using highly- ergent standard single-mode fiber (SMF). The reduction in both beam ergence and insertion losses for the GIF configuration compared with SMF was characterized for a 10.0 mm channel. Absorption spectroscopy was demonstrated on chip for the measurement of red color dye (Ponceau 4R), and the detection of thiocyanate in water and artificial human saliva. The proposed optofluidic setup allows for absorption spectroscopy measurements to be performed with only 200 µL of solution which is an order of magnitude smaller than for standard cuvettes but provides a comparable sensitivity. The approach could be integrated into a lab-on-a-chip system that is compact and does not require free-space optics to perform absorption spectroscopy.
Impact of Nanoscale Surface Heterogeneity on Precursor Film Growth and Macroscopic Spreading of [Rmim][NTf2] Ionic Liquids on Mica
Publisher: American Chemical Society (ACS)
Date: 27-08-2013
DOI: 10.1021/LA402668V
Abstract: The connection between the interfacial properties of ionic liquids and their wetting behavior has been studied very little to date and not at all on heterogeneous surfaces. Therefore, we have investigated the static and dynamic wetting for a family of ionic liquids, 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [Rmim][NTf2], on mica, where R represents an ethyl, butyl, or hexyl alkyl chain on the imidazolium ring. Spreading is impacted greatly by a precursor film that forms on both homogeneous and heterogeneous mica surfaces. Macroscopically, the initial viscous spreading of the ionic liquid droplet on bare mica occurs within seconds but is then followed by a very slow relaxation that can be closely correlated with the typical time-scales of the precursor film growth. The contact angle for [emim][NTf2] and [bmim][NTf2] relaxes from about 40° to 23° over 30 and 90 min, respectively. For [hmim][NTf2], the process takes approximately 24 h and approaches complete wetting. The thickness of the precursor films for [emim][NTf2], [bmim][NTf2], and [hmim][NTf2] were 0.53, 0.65, and 1.0 nm, respectively, according to atomic force microscopy (AFM). These values are consistent with a monolayer of ionic liquid cations on mica, rather than ion pairs. A monolayer of octadecylphosphonic acid (OPA) on mica prevents both the formation of a precursor film and the relaxation of the contact angle. However, only a partial surface coverage of ~60% OPA is required to have the same effect. Quenching of precursor film formation (and associated contact angle relaxation) is due to an increasingly connected network of OPA regions that closes the nanoscale paths of bare mica on which the precursor film can develop via surface diffusion.
Fabrication and Operation of a Microcavity Plasma Array Device for Microscale Surface Modification
Publisher: Wiley
Date: 05-03-2012
Graded-index fiber on-chip absorption spectroscopy
Publisher: Optica Publishing Group
Date: 2021
DOI: 10.1364/CLEO_AT.2021.AW3T.7
Abstract: Absorption spectroscopy is demonstrated with microfluidic devices using collimating graded-index fibers. The optofluidics setup allows for absorption measurements to be performed with 10x smaller volumes than for standard cuvettes but with comparable sensitivity.
Microbial cell lysis and nucleic acid extraction via nanofluidic channel
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA01336D
Abstract: This paper presents a microfluidic device with a nano-channel prepared by focused ion beam (FIB) milling for microbial cell lysis and nucleic acid extraction.
Electrowetting of Aqueous Solutions of Ionic Liquid in Solid−Liquid−Liquid Systems
Publisher: American Chemical Society (ACS)
Date: 15-04-2010
DOI: 10.1021/JP912115N
Intestine-on-a-chip microfluidic model for efficient in vitro screening of oral chemotherapeutic uptake
Publisher: American Chemical Society (ACS)
Date: 30-05-2017
Wettability of Photoresponsive Titanium Dioxide Surfaces
Publisher: American Chemical Society (ACS)
Date: 20-03-2003
DOI: 10.1021/LA020660C
Capillary Filling of Nanoscale Channels and Surface Structure
Publisher: Wiley
Date: 11-09-2014
Abstract: Nanoscale surface structures and channels are of intense interest for the very high surface‐to‐volume ratios involved. For extremely small systems, it may become difficult to distinguish between bulk and interface as well as their respective effects on the fluid volume. We review capillary filling of nanochannels and wicking in nanoscale surface structures. Both processes are of fundamental importance for the initial filling and successful operation of nanofluidic devices. We conclude that, despite the small scales involved, Washburn’s description of the spontaneous capillary filling of nanochannels is reliable. Similarly, nanowicking follows conventional capillarity theory closely. Nonetheless, open questions remain about the role and significance of line tension, precursor films and contact line pinning. The exact consequences of a diffuse interface or contact line are yet to be fully understood.
Pilot-scale microfluidic solvent extraction of high-value metals
Publisher: Elsevier BV
Date: 05-2022
Asymmetric Wetting Hysteresis on Chemical Defects
Publisher: American Physical Society (APS)
Date: 13-07-2007
An Open Microfluidic Chip for Continuous Sampling of Solute from a Turbulent Particle Suspension
Publisher: Wiley
Date: 27-11-2021
Interfacial Phenomena and Fluid Control in Micro/Nanofluidics
Publisher: Springer Science and Business Media LLC
Date: 2016
Abstract: Fundamental aspects of rapidly advancing micro/nanofluidic devices are reviewed from the perspective of liquid interface chemistry and physics, including the influence of capillary pressure in microfluidic two-phase flows and phase transitions related to capillary condensation.
Evaporation-Driven Flow in Micropillar Arrays: Transport Dynamics and Chemical Analysis under Varied Sample and Ambient Conditions
Publisher: American Chemical Society (ACS)
Date: 03-12-2020
Caged-Sphere Optofluidic Sensors: Whispering Gallery Resonators in Wicking Microfluidics
Publisher: MDPI AG
Date: 29-05-2022
DOI: 10.3390/S22114135
Abstract: The rapid development of optofluidic technologies in recent years has seen the need for sensing platforms with ease-of-use, simple s le manipulation, and high performance and sensitivity. Herein, an integrated optofluidic sensor consisting of a pillar array-based open microfluidic chip and caged dye-doped whispering gallery mode microspheres is demonstrated and shown to have potential for simple real-time monitoring of liquids. The open microfluidic chip allows for the wicking of a thin film of liquid across an open surface with subsequent evaporation-driven flow enabling continuous passive flow for s ling. The active dye-doped whispering gallery mode microspheres placed between pillars, avoid the use of cumbersome fibre tapers to couple light to the resonators as is required for passive microspheres. The performance of this integrated sensor is demonstrated using glucose solutions (0.05–0.3 g/mL) and the sensor response is shown to be dynamic and reversible. The sensor achieves a refractive index sensitivity of ~40 nm/RIU, with Q-factors of ~5 × 103 indicating a detection limit of ~3 × 10−3 RIU (~20 mg/mL glucose). Further enhancement of the detection limit is expected by increasing the microsphere Q-factor using high-index materials for the resonators, or alternatively, inducing lasing. The integrated sensors are expected to have significant potential for a host of downstream applications, particularly relating to point-of-care diagnostics.
Dynamic x-ray optics with microfluidics: stabilization of gas bubbles by surface ordering and freezing
Publisher: Informa UK Limited
Date: 12-2009
DOI: 10.1051/LHB/2009090
Dynamics of capillary-driven liquid-liquid displacement in open microchannels
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4CP03910F
Abstract: For capillary-driven liquid–liquid displacement in rectangular open microchannels, the square of the position of the liquid–liquid front increases linearly with time, whereas the flow velocity decreases with increasing channel width.
Electrochemical behavior of oxazoline-based plasma polymers for biosensing applications
Publisher: Wiley
Date: 25-04-2023
Abstract: Plasma‐polymerized polyoxazoline (POx) thin films offer a fast, scalable, and solvent‐free method of electrode functionalization through the unique chemistry of the oxazoline ring. However, for POx to be a viable green alternative to existing surface modification approaches, the films should be able to withstand the processing steps involved in biosensing. Here, the effects that current exposure, extended incubation, and repeated electrode rinses have on the electrochemical and physical stability of polymethyloxazoline thin films are investigated. The films are observed to become more diffusive after incubation and rinse steps. While no significant changes in chemistry were observed, a marked change in nanotopography occurred after exposure to current, suggesting a change in the polymer film structure.
Inferring wettability of heterogeneous surfaces by ToF-SIMS
Publisher: Elsevier BV
Date: 04-2008
DOI: 10.1016/J.JCIS.2008.01.042
Abstract: Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been examined as a possible predictive tool for surface wettability. Heterogeneous surfaces were prepared with hydrophilic and hydrophobic regions of known surface coverage using self-assembled monolayers. The surface coverage of each component was then correlated with ToF-SIMS fragmentation of the hydrophobic and hydrophilic surface groups and static contact angle measurements. From these measurements, a clear relationship between the surface wettability and relative intensity of characteristic secondary ions was identified. Moreover, our results for planar surfaces can be extrapolated to predict the wettability of particulate s les for which direct contact angle measurements are not straightforward. The ability to infer particle wettability by ToF-SIMS is well suited to mineral characterization and in particular, the prediction of mineral flotation efficiencies.
Numbering-up Y–Y microfluidic chips for higher-throughput solvent extraction of platinum(IV) chloride
Publisher: Springer Science and Business Media LLC
Date: 16-09-2016
Reversible colorimetric sensing of volatile analytes by wicking in close proximity to a photonic film
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2RA06740D
Abstract: Isolation of volatile analytes from fluid s les is a rate-determining step that can delay sensor response time. An optofluidic sensing platform capable of rapidly detecting gas-phase analytes from flowing micro-volume fluid s les is reported.
Chemical and biomolecule patterning on 2D surfaces using atmospheric pressure microcavity plasma array devices
Publisher: SPIE
Date: 21-12-2011
DOI: 10.1117/12.903304
A Multi-Stream Microchip for Process Intensification of Liquid-Liquid Extraction
Publisher: Wiley
Date: 08-05-2017
Discrete microfluidics: Reorganizing droplet arrays at a bend
Publisher: AIP Publishing
Date: 12-10-2009
DOI: 10.1063/1.3240883
Abstract: Microfluidic manipulation of densely packed droplet arrangements (i.e., gel emulsions) using sharp microchannel bends was studied as a function of bend angle, droplet volume fraction, droplet size, and flow velocity. Emulsion reorganization was found to be specifically dependent on the pathlength that the droplets are forced to travel as they navigate the bend under spatial confinement. We describe how bend-induced droplet displacements might be exploited in complex, droplet-based microfluidics.
Effect of mould roughness on injection moulded poly (methyl methacrylate) surfaces: Roughness and wettability
Publisher: Elsevier BV
Date: 12-2019
A Multiplexed Microfluidic Platform toward Interrogating Endocrine Function: Simultaneous Sensing of Extracellular Ca2+ and Hormone
Publisher: American Chemical Society (ACS)
Date: 15-01-2020
DOI: 10.1021/ACSSENSORS.9B02308
Abstract: Extracellular Ca
Manipulation of gel emulsions by variable microchannel geometry
Publisher: Royal Society of Chemistry (RSC)
Date: 2009
DOI: 10.1039/B808160C
Abstract: In this article we investigate the morphology and manipulation of monodisperse emulsions at high dispersed phase volume fractions (gel emulsions) in a microfluidic environment. Confined monodisperse gel emulsions self-organize into well-ordered droplet arrangements, which may be stable or metastable, depending on the geometry of the confining microchannel. Three arrangements are considered, in which the droplets are aligned in a single file, a two row, or a three row arrangement. We explore the potential for induced transitions between these distinct droplet arrangements as a tool for droplet-based microfluidic processing. Transitions are readily achieved by means of localized (geometrical) features in channel geometry, however the onset of the transition is strongly dependent on the subtleties of the microfluidic system, e.g. volume fraction, droplet size, and feature dimensions. The transitions can be achieved via fixed channel features or, when the continuous phase is a ferrofluid, by a virtual channel constriction created using a magnetic field.
Reducing Premature Coronary Artery Disease in Malaysia by Early Identification of Familial Hypercholesterolemia Using the Familial Hypercholesterolemia Case Ascertainment Tool (FAMCAT): Protocol for a
Publisher: JMIR Publications Inc.
Date: 02-06-2023
DOI: 10.2196/47911
Abstract: Familial hypercholesterolemia (FH) is predominantly caused by mutations in the 4 FH candidate genes (FHCGs), namely, low-density lipoprotein receptor (LDLR), apolipoprotein B-100 (APOB-100), proprotein convertase subtilisin/kexin type 9 (PCSK9), and the LDL receptor adaptor protein 1 (LDLRAP1). It is characterized by elevated low-density lipoprotein cholesterol (LDL-c) levels leading to premature coronary artery disease. FH can be clinically diagnosed using established clinical criteria, namely, Simon Broome (SB) and Dutch Lipid Clinic Criteria (DLCC), and can be identified using the Familial Hypercholesterolemia Case Ascertainment Tool (FAMCAT), a primary care screening tool. This study aims to (1) compare the detection rate of genetically confirmed FH and diagnostic accuracy between the FAMCAT, SB, and DLCC in the Malaysian primary care setting (2) identify the genetic mutation profiles, including novel variants, in in iduals with suspected FH in primary care (3) explore the experience, concern, and expectation of in iduals with suspected FH who have undergone genetic testing in primary care and (4) evaluate the clinical utility of a web-based FH Identification Tool that includes the FAMCAT, SB, and DLCC in the Malaysian primary care setting. This is a mixed methods evaluation study conducted in 11 Ministry of Health primary care clinics located at the central administrative region of Malaysia. In Work stream 1, the diagnostic accuracy study design is used to compare the detection rate and diagnostic accuracy of the FAMCAT, SB, and DLCC against molecular diagnosis as the gold standard. In Work stream 2, the targeted next-generation sequencing of the 4 FHCGs is used to identify the genetic mutation profiles among in iduals with suspected FH. In Work stream 3a, a qualitative semistructured interview methodology is used to explore the experience, concern, and expectation of in iduals with suspected FH who have undergone genetic testing. Lastly, in Work stream 3b, a qualitative real-time observation of primary care physicians using the “think-aloud” methodology is applied to evaluate the clinical utility of a web-based FH Identification Tool. The recruitment for Work stream 1, and blood s ling and genetic analysis for Work stream 2 were completed in February 2023. Data collection for Work stream 3 was completed in March 2023. Data analysis for Work streams 1, 2, 3a, and 3b is projected to be completed by June 2023, with the results of this study anticipated to be published by December 2023. This study will provide evidence on which clinical diagnostic criterion is the best to detect FH in the Malaysian primary care setting. The full spectrum of genetic mutations in the FHCGs including novel pathogenic variants will be identified. Patients’ perspectives while undergoing genetic testing and the primary care physicians experience in utilizing the web-based tool will be established. These findings will have tremendous impact on the management of patients with FH in primary care and subsequently reduce their risk of premature coronary artery disease. DERR1-10.2196/47911
Microfluidic Screening to Study Acid Mine Drainage
Publisher: American Chemical Society (ACS)
Date: 21-10-2020
An Open Microfluidic Chip for Continuous Sampling of Solute from a Turbulent Particle Suspension
Publisher: Wiley
Date: 27-11-2021
Plasma deposited polyoxazoline films integration into spiral microfluidics for the targeted capture of size selected cells
Publisher: Frontiers Media SA
Date: 20-05-2021
DOI: 10.3389/FCHEM.2021.690781
Abstract: Biomolecules readily and irreversibly bind to plasma deposited Polyoxazoline thin films in physiological conditions. The unique reactivity of these thin films toward antibodies is driving the development of immunosensing platforms for applications in cancer diagnostics. However, in order for these coatings to be used as advanced immunosensors, they need to be incorporated into microfluidic devices that are sealed via plasma bonding. In this work, the thickness, chemistry and reactivity of the polyoxazoline films were assessed following plasma activation. Films deposited from methyl and isopropenyl oxazoline precursors were integrated into spiral microfluidic devices and biofunctionalized with prostate cancer specific antibodies. Using microbeads as model particles, the design of the spiral microfluidic was optimised to enable the size-based isolation of cancer cells. The device was tested with a mixed cell suspension of healthy and malignant prostate cells. The results showed that, following size-specific separation in the spiral, selective capture was achieved on the immunofunctionalised PPOx surface. This proof of concept study demonstrates that plasma deposited polyoxazoline can be used for immunosensing in plasma bonded microfluidic devices.
Electrowetting of Ionic Liquids on Teflon AF1600 in Ambient Hexadecane
Publisher: Informa UK Limited
Date: 17-05-2012
Pinning and wicking in regular pillar arrays
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4SM00684D
Abstract: Pinning and wicking of a liquid meniscus in a square array of pillars is investigated in numerical energy minimizations and compared to wetting experiments.
Microfluidic Cell Microarray Platform for High Throughput Analysis of Particle–Cell Interactions
Publisher: American Chemical Society (ACS)
Date: 02-03-2018
Influence of sample volume and solvent evaporation on absorbance spectroscopy in a microfluidic pillar-cuvette
Publisher: Springer Science and Business Media LLC
Date: 2016
Microfluidic solvent extraction, stripping, and phase disengagement for high-value platinum chloride solutions
Publisher: Elsevier BV
Date: 12-2015
Pillar cuvettes: Capillary-filled, microliter quartz cuvettes with microscale path lengths for optical spectroscopy
Publisher: American Chemical Society (ACS)
Date: 20-04-2015
Ultra-high-resolution greyscale fluorescence images via UV-exposure of thin flexible phosphor films
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2NR02931F
Abstract: High resolution greyscale fluorescence images created in thin phosphor films using UV light.
Multiparameter toxicity screening on a chip: Effects of UV radiation and titanium dioxide nanoparticles on HaCaT cells
Publisher: AIP Publishing
Date: 07-2019
DOI: 10.1063/1.5113729
Abstract: Microfluidic screening is gaining attention as an efficient method for evaluating nanomaterial toxicity. Here, we consider a multiparameter treatment where nanomaterials interact with cells in the presence of a secondary exposure (UV radiation). The microfluidic device contains channels that permit immobilization of HaCaT cells (human skin cell line), delivery of titanium dioxide nanoparticles (TNPs), and exposure to a known dose of UV radiation. The effect of single-parameter exposures (UV or TNP) was first studied as a benchmark, and then multiparameter toxicity (UV and TNP) at different concentrations was explored. The results demonstrate a concentration-dependent protective effect of TNP when exposed to UV irradiation.
Low-temperature bonding process for the fabrication of hybrid glass-membrane organ-on-a-chip devices
Publisher: SPIE-Intl Soc Optical Eng
Date: 07-12-2016
Crossed flow microfluidics for high throughput screening of bioactive chemical-cell interactions
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6LC01261B
Abstract: A crossed flow microfluidic device was used for generation of cell-based arrays aiming for high throughput screening of applied bioactive chemicals to captured cells.
Injection moulding of micropillar arrays: a comparison of poly(methyl methacrylate) and cyclic olefin copolymer
Publisher: Springer Science and Business Media LLC
Date: 03-08-2022
DOI: 10.1007/S00542-022-05350-4
Abstract: Injection moulding of micropillar arrays offers a fast and inexpensive method for manufacturing sensors, optics, lab-on-a-chip devices, and medical devices. Material choice is important for both the function of the device and manufacturing optimisation. Here, a comparative study of poly(methyl methacrylate) (PMMA) and cyclic olefin copolymer (COC) injection moulding of micropillar arrays is presented. These two polymers are chosen for their convenient physical, chemical, and optical properties, which are favoured for microfluidic devices. COC is shown to replicate the mould’s nano/microstructures more precisely than PMMA. COC successfully forms a micropillar array (250 mm diameter 496 mm high) and closely replicates surfaces with nano-scale roughness (30–120 nm). In the same moulds, PMMA forms lens arrays (not true pillars) and smoother surfaces due to the incomplete filling for all parameters studied. Thus, COC offers finer structural detail for devices that require micro and nano-structured features, and may be more suited to injection moulding microfluidic devices.
Critical elements: opportunities for microfluidic processing and potential for ESG-powered mining investments
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2GC02214A
Abstract: Critical minerals have an irreplaceable role in the ongoing revolution in technology and using microfluidic continuous-flow technology for processing these minerals has potential solutions and benefits towards the ESG mining issues.
Sensing intra- and extra-cellular Ca2? in the islet of Langerhans
Publisher: Wiley
Date: 05-11-2022
Abstract: Calcium ions (Ca 2+ ) take part in intra‐ and inter‐cellular signaling to mediate cellular functions. Sensing this ubiquitous messenger is instrumental in disentangling the specific functions of cellular sub‐compartments and/or intercellular communications. In this review, the authors first describe intra‐ and inter‐cellular Ca 2+ signaling in relation to insulin secretion from the pancreatic islets, and then outline the development of erse sensors, for ex le, chemically synthesized indicators, genetically encoded proteins, and ion‐selective microelectrodes, for intra‐ and extra‐cellular sensing of Ca 2+ . Particular emphasis is placed on emerging approaches in this field, such as low‐affinity Ca 2+ indicators and unique Ca 2+ ‐responsive composite materials. The authors conclude by remarking on the challenges and opportunities for further developments in this field, which may facilitate a more comprehensive understanding of Ca 2+ signaling within and outside the islets, and its relevance in health and disease.
Microfluidic Platform for High-Throughput Screening of Leach Chemistry
Publisher: American Chemical Society (ACS)
Date: 20-06-2018
Investigation of Chalcopyrite Leaching Using an Ore-on-a-Chip
Publisher: American Chemical Society (ACS)
Date: 10-12-2019
Low-temperature bonded glass-membrane microfluidic device for in vitro organ-on-a-chip cell culture models
Publisher: SPIE
Date: 22-12-2015
DOI: 10.1117/12.2202461
The influence of nanopore dimensions on the electrochemical properties of nanopore arrays studied by impedance spectroscopy
Publisher: MDPI AG
Date: 11-11-2014
DOI: 10.3390/S141121316
Electrochemical Proteus vulgaris whole cell urea sensor in synthetic urine
Publisher: Elsevier BV
Date: 11-2019
Influence of the Work of Adhesion on the Dynamic Wetting of Chemically Heterogeneous Surfaces
Publisher: American Chemical Society (ACS)
Date: 25-10-2008
DOI: 10.1021/LA802264D
Abstract: The velocity dependence of the dynamic contact angle for a glycerol-water mixture wetting two different chemically heterogeneous surfaces (mixed thiols on gold and partially methylated titania, 16 s les in all) was studied. The molecular kinetic theory (MKT) of wetting was used to interpret the dynamic contact angle data. The equilibrium displacement frequency ( K 0) was predominantly determined by the viscous contribution from the bulk liquid, with a minor contribution from the surface. The mean distance between surface sites (lambda) decreased with increasing work of adhesion. The contact line friction coefficient zeta 0 was found to vary exponentially with the work of adhesion, enabling the unit flow volume of the liquid to be obtained.
Loading of 5-fluorouracil onto halloysite nanotubes for targeted drug delivery using a subcritical gas antisolvent process (GAS)
Publisher: Elsevier BV
Date: 05-2020
Intracellular delivery of mRNA to human primary T cells with microfluidic vortex shedding
Publisher: Springer Science and Business Media LLC
Date: 03-2019
DOI: 10.1038/S41598-019-40147-Y
Abstract: Intracellular delivery of functional macromolecules, such as DNA and RNA, across the cell membrane and into the cytosol, is a critical process in both biology and medicine. Herein, we develop and use microfluidic chips containing post arrays to induce microfluidic vortex shedding , or μVS , for cell membrane poration that permits delivery of mRNA into primary human T lymphocytes. We demonstrate transfection with μVS by delivery of a 996-nucleotide mRNA construct encoding enhanced green fluorescent protein (EGFP) and assessed transfection efficiencies by quantifying levels of EGFP protein expression. We achieved high transfection efficiency (63.6 ± 3.44% EGFP + viable cells) with high cell viability (77.3 ± 0.58%) and recovery (88.7 ± 3.21%) in CD3 + T cells 19 hrs after μVS processing. Importantly, we show that processing cells via μVS does not negatively affect cell growth rates or alter cell states. We also demonstrate processing speeds of greater than 2.0 × 10 6 cells s −1 at volumes ranging from 0.1 to 1.5 milliliters. Altogether, these results highlight the use of μVS as a rapid and gentle delivery method with promising potential to engineer primary human cells for research and clinical applications.
A quantitative experimental study of wetting hysteresis on discrete and continuous chemical heterogeneities
Publisher: Springer Science and Business Media LLC
Date: 03-10-2012
Structure-induced spreading of liquid in micropillar arrays
Publisher: Springer Science and Business Media LLC
Date: 17-08-2011
Precipitation of Drug Particles Using a Gas Antisolvent Process on a High-Pressure Microfluidic Platform
Publisher: American Chemical Society (ACS)
Date: 02-06-2020
Controlled electrocoalescence in microfluidics: Targeting a single lamella
Publisher: AIP Publishing
Date: 25-09-2006
DOI: 10.1063/1.2357039
Abstract: Electrocoalescence of aqueous droplets is investigated as a tool for microfluidic processing. Where droplets are separated by only thin lamellae, coalescence can be induced on demand within a fraction of a millisecond at low potentials (few volts). The authors show that in their approach electrocoalescence proceeds through an electric-field-induced dynamic instability of the oil/water interface. When the electrode geometry and applied potential are optimized, in idual lamellae can be targeted for rupture within highly ordered droplet arrangements.
The Use of Microfluidics in Cytotoxicity and Nanotoxicity Experiments
Publisher: MDPI AG
Date: 12-04-2017
DOI: 10.3390/MI8040124
Photometric Sensing of Active Chlorine, Total Chlorine, and pH on a Microfluidic Chip for Online Swimming Pool Monitoring
Publisher: MDPI AG
Date: 30-05-2020
DOI: 10.3390/S20113099
Abstract: A microfluidic sensor was studied for the photometric detection of active chlorine, total chlorine, and pH in swimming pool s les. The sensor consisted of a four-layer borosilicate glass chip, containing a microchannel network and a 2.2 mm path length, 1.7 mL optical cell. The chip was optimised to measure the bleaching of methyl orange and spectral changes in phenol red for quantitative chlorine (active and total) and pH measurements that were suited to swimming pool monitoring. Reagent consumption (60 mL per measurement) was minimised to allow for maintenance-free operation over a nominal summer season (3 months) with minimal waste. The chip was tested using s les from 12 domestic, public, and commercial swimming pools (indoor and outdoor), with results that compare favourably with commercial products (test strips and the N,N’-diethyl-p-phenylenediamine (DPD) method), precision pH electrodes, and iodometric titration.
Multiomics approach unravels fertility transition in a pigeonpea line for a two‐line hybrid system
Publisher: Wiley
Date: 18-06-2020
DOI: 10.1002/TPG2.20028
The timing of application and inclusion of a surfactant are important for absorption and translocation of foliar phosphoric acid by wheat leaves
Publisher: Frontiers Media SA
Date: 22-11-2019
Directed crystallisation of zinc oxide on patterned surfaces
Publisher: Elsevier BV
Date: 11-2006
DOI: 10.1016/J.JCIS.2006.07.078
Abstract: Patterned self-assembled monolayers of functionalised alkane thiols were prepared on gold substrates, using UV-photolithography. Two alkane thiols, 11-mercaptoundecanoic acid (MUA) and a fluorinated decane thiol (FDT, CF3(CF2)7CH2CH2SH) were used to fabricate chemically structured surfaces which served as templates for zinc oxide (ZnO) crystallisation. When these patterns, containing high (MUA) and low (FDT) surface energy regions were exposed to a 10 mM zinc nitrate crystallising solution, nucleation occurred selectively on the low energy regions. After 90 min, hexagonal prisms had grown upright on these areas. The crystal growth is uniform with a crystal length of about 1 mum and a diameter between 50 and 100 nm. We attribute the selective growth to a combination of crystallographic frustration of the zinc ions on the high energy regions and an accumulation of hydroxide ions on the low energy regions.
Microplasma patterning of bonded microchannels using high-precision “injected” electrodes
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0LC00339E
Abstract: A rapid, high-precision method for localised plasma-treatment of bonded PDMS microchannels is demonstrated. Patterned electrodes were prepared by injection of molten gallium into preformed microchannel guides. The electrode guides were prepared without any additional fabrication steps compared to conventional microchannel fabrication. Alignment of the "injected" electrodes is precisely controlled by the photomask design, rather than positioning accuracy of alignment tools. Surface modification is detected using a fluorescent dye (Rhodamine B), revealing a well-defined micropattern with regions less than 100 µm along the length of the microchannel.
Asymmetric Wetting Hysteresis on Hydrophobic Microstructured Surfaces
Publisher: American Chemical Society (ACS)
Date: 10-03-2009
DOI: 10.1021/LA804246A
Abstract: The wetting behavior of hydrophobic, microstructured surfaces containing arrays of pillars or holes has been investigated. The size of the surface features was fixed (20 microm), while their separation was varied to adjust the area fraction (0-80%). The wettability of structured surfaces for liquids resting in the Cassie state is strongly dependent on the continuity of the solid component. Microstructured square pillars and holes showed distinct, asymmetric wetting hysteresis, consistent with our previous observations on flat, chemically heterogeneous surfaces. Furthermore, clear trends for the magnitude of contact angle hysteresis versus area fraction for the two types of microstructured surfaces are evident. The pinning energy associated with these surface features is estimated.
Continuous monitoring of EDTA extractable iron from mineral slurries using a microfluidic chip
Publisher: Wiley
Date: 06-03-2022
DOI: 10.1002/CJCE.24343
Abstract: In mineral processing, iron oxidation species formed on the mineral surface play a dominant role in depressing mineral flotation and must be monitored. Current analytical methods rely on off‐line s le preparation followed by conventional analytical techniques, which are labour intensive and time delayed. This paper reports the successful application of an open microfluidic chip for real‐time continuous monitoring of ethylenediaminetetraacetic acid (EDTA) extractable iron (derived from iron oxidation species) in mineral slurries. A detailed mineralogical study of the mineral ore before and after leaching by EDTA has been undertaken to understand the leaching behaviour of the EDTA‐slurry extraction system, showing good agreement with solution analysis.
Microfluidic polymer multilayer adsorption on liquid crystal droplets for microcapsule synthesis
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B808826H
Abstract: Exploiting microfluidic principles, the potential for chip-based multilayer assembly for the synthesis of polymer microcapsules was investigated. We demonstrate that continuous flow microfluidic multilayer synthesis is a fast, efficient, automated alternative to conventional batch synthesis. In this work, we dispersed liquid crystal (LC) molecules (organic phase) as monodisperse droplets in an aqueous continuous phase containing the primary polymer and a suitable surfactant. The primary polymer was coadsorbed with the surfactant at the organic/aqueous interface, stabilizing the LC droplets against coalescence and providing a template for subsequent polymer adsorption. As the droplet templates are transported through the microfluidic channel, the polymer-containing aqueous continuous phase is selectively withdrawn and replaced with rinse solution, and then with an alternative polymer solution. This selective withdrawal and infusion cycle was repeated to assemble polymer multilayers onto the emulsion droplets. The process was followed using fluorescence microscopy of the fluorescently-labelled polymers at the LC interface and of the flowing polymer solutions during the sequential rinse stages. Cross-linking of the multilayers and removal of the dispersed LC phase resulted in polymer capsules retaining the high monodispersity of the droplet templates. This microfluidic approach significantly reduces the multilayer formation time (to <2 min for 3-layer capsules) of well-defined capsules that are envisaged to have benefits in biomedical applications, including drug delivery and encapsulated biochemical reactions.
Static and Dynamic Electrowetting of an Ionic Liquid in a Solid/Liquid/Liquid System
Publisher: American Chemical Society (ACS)
Date: 27-05-2010
DOI: 10.1021/JA9106397
Abstract: A droplet of an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, bmim.BF(4)) is immersed in an immiscible liquid (n-hexadecane) and electrowetted on a flat Teflon AF1600-coated ITO electrode. The static contact angle decreases significantly when voltage is applied between the droplet and the electrode: from 145 degrees down to 50 degrees (with DC voltage) and 15 degrees (with AC voltage). The electrowetting curves (contact angle versus voltage) are similar to the ones obtained in other solid/liquid/vapor and solid/liquid/liquid systems: symmetric with respect to zero voltage and correctly described by Young-Lippmann equation below saturation. The reversibility is excellent and contact angle hysteresis is minimal (approximately 2 degrees). The step size used in applying the DC voltage and the polarity of the voltage are unimportant. The saturation contact angle cannot be predicted with the simple zero-interfacial tension theory. Spreading (after applying a DC voltage) and retraction (after switching off the voltage) of the droplet is monitored. The base area of the droplet varies exponentially during wetting (exponential saturation) and dewetting (exponential decay). The characteristic time is 20 ms for spreading and 35 ms for retraction (such asymmetry is not observed with water-glycerol mixtures of a similar viscosity). The spreading kinetics (dynamic contact angle versus contact line speed) can be described by the hydrodynamic model (Voinov's equation) for small contact angles and by the molecular-kinetic model (Blake's equation) for large contact angles. The role of viscous and molecular dissipation follows the scheme outlined by Brochard-Wyart and de Gennes.
Optimization of binding B-lymphocytes in a microfluidic channel: surface modification, stasis time and shear response
Publisher: IOP Publishing
Date: 30-11-2017
Therapeutic mammaplasty is a safe and effective alternative to mastectomy with or without immediate breast reconstruction
Publisher: Oxford University Press (OUP)
Date: 19-02-2020
DOI: 10.1002/BJS.11468
Abstract: Therapeutic mammaplasty (TM) may be an alternative to mastectomy, but few well designed studies have evaluated the success of this approach or compared the short-term outcomes of TM with mastectomy with or without immediate breast reconstruction (IBR). Data from the national iBRA-2 and TeaM studies were combined to compare the safety and short-term outcomes of TM and mastectomy with or without IBR. The subgroup of patients in the TeaM study who underwent TM to avoid mastectomy were identified, and data on demographics, complications, oncology and adjuvant treatment were compared with those of patients undergoing mastectomy with or without IBR in the iBRA-2 study. The primary outcome was the percentage of successful breast-conserving procedures in the TM group. Secondary outcomes included postoperative complications and time to adjuvant therapy. A total of 2916 patients (TM 376 mastectomy 1532 mastectomy and IBR 1008) were included in the analysis. Patients undergoing TM were more likely to be obese and to have undergone bilateral surgery than those having IBR. However, patients undergoing mastectomy with or without IBR were more likely to experience complications than the TM group (TM: 79, 21·0 per cent mastectomy: 570, 37·2 per cent mastectomy and IBR: 359, 35·6 per cent P & 0·001). Breast conservation was possible in 87·0 per cent of patients who had TM, and TM did not delay adjuvant treatment. TM may allow high-risk patients who would not be candidates for IBR to avoid mastectomy safely. Further work is needed to explore the comparative patient-reported and cosmetic outcomes of the different approaches, and to establish long-term oncological safety.
Evaluating the antifouling effects of silver nanoparticles regenerated by TiO2 on forward osmosis membrane
Publisher: Elsevier BV
Date: 03-2014
Rapid Fabrication of Superhydrophobic Virtual Walls for Microfluidic Gas Extraction and Sensing
Publisher: MDPI AG
Date: 02-05-2021
DOI: 10.3390/MI12050514
Abstract: Based on the virtual walls concept, where fluids are guided by wettability, we demonstrate the application of a gas phase extraction microfluidic chip. Unlike in previous work, the chip is prepared using a simple, rapid, and low-cost fabrication method. Channels were cut into double-sided adhesive tape (280 µm thick) and bonded to hydrophilic glass slides. The tape was selectively made superhydrophobic by ‘dusting’ with hydrophobic silica gel to enhance the wettability contrast at the virtual walls. Finally, the two glass slides were bonded using tape, which acts as a spacer for gas transport from/to the guided liquids. In our ex le, the virtual walls create a stable liquid–vapor–liquid flow configuration for the extraction of a volatile analyte (ammonia), from one liquid stream to the other through the intermediate vapor phase. The collector stream contained a pH indicator to visualize the mass transport. Quantitative analysis of ammonium hydroxide in the s le stream ( mM) was possible using a characteristic onset time, where the first pH change in the collector stream was detected. The effect of gap length, flow rates, and pH of the collector stream on the onset time is demonstrated. Finally, we demonstrate the analysis of ammonium hydroxide in artificial human saliva to show that the virtual walls chip is suitable for extracting volatile analytes from biofluids.
Microengineered bioartificial liver chip for drug toxicity screening
Publisher: Wiley
Date: 21-05-2018
Femtoliter Droplet Handling in Nanofluidic Channels: A Laplace Nanovalve
Publisher: American Chemical Society (ACS)
Date: 07-12-2012
DOI: 10.1021/AC3028905
Abstract: Analytical technologies of ultrasmall volume liquid, in particular femtoliter to attoliter liquid, is essential for single-cell and single-molecule analysis, which is becoming highly important in biology and medical diagnosis. Nanofluidic chips will be a powerful tool to realize chemical processes for such a small volume s le. However, a technical challenge exists in fluidic control, which is femtoliter to attoliter liquid generation in air and handling for further chemical analysis. Integrating mechanical valves fabricated by MEMS (microelectric mechanical systems) technology into nanofluidic channels is difficult. Here, we propose a nonmechanical valve, which is a Laplace nanovalve. For this purpose, a nanopillar array was embedded in a nanochannel using a two-step electron beam lithography and dry-etching process. The nanostructure allowed precise wettability patterning with a resolution below 100 nm, which was difficult by photochemical wettability patterning due to the optical diffraction. The basic principle of the Laplace nanovalve was verified, and a 1.7 fL droplet (water in air) was successfully generated and handled for the first time.
Generation of monodisperse gel emulsions in a microfluidic device
Publisher: AIP Publishing
Date: 09-01-2006
DOI: 10.1063/1.2164393
Abstract: We demonstrate that high dispersed phase volume fraction emulsions (i.e., gel emulsions) can be prepared in situ for microfluidic applications. Previously, the production of gel-like emulsions in microfluidic devices, where the droplet size is less than the length-scale of the channel, required multistep splitting of larger droplets in a branched microchannel network. Instead, we employ an abrupt change in the aspect ratio of a single microchannel to rapidly destabilize a confined coflowing stream, forming highly monodisperse droplets (coefficient of variance & .5%). Using this emulsification mechanism, gel emulsions can be prepared in a single production step.
Surface patterning of bonded microfluidic channels
Publisher: AIP Publishing
Date: 09-2010
DOI: 10.1063/1.3493643
Abstract: Microfluidic channels in which multiple chemical and biological processes can be integrated into a single chip have provided a suitable platform for high throughput screening, chemical synthesis, detection, and alike. These microchips generally exhibit a homogeneous surface chemistry, which limits their functionality. Localized surface modification of microchannels can be challenging due to the nonplanar geometries involved. However, chip bonding remains the main hurdle, with many methods involving thermal or plasma treatment that, in most cases, neutralizes the desired chemical functionality. Postbonding modification of microchannels is subject to many limitations, some of which have been recently overcome. Novel techniques include solution-based modification using laminar or capillary flow, while conventional techniques such as photolithography remain popular. Nonetheless, new methods, including localized microplasma treatment, are emerging as effective postbonding alternatives. This Review focuses on postbonding methods for surface patterning of microchannels.
Contact Line Pinning on Microstructured Surfaces for Liquids in the Wenzel State
Publisher: American Chemical Society (ACS)
Date: 24-08-2009
DOI: 10.1021/LA902296D
Abstract: The wettability of surfaces microstructured with square pillars was studied, where the static advancing contact angle on the planar surface was 72 degrees. We observed elevated advancing angles (up to 140 degrees) on these structures for droplets in the Wenzel state. No air was trapped in the structured surfaces beneath the liquid, ruling out the well-known Lotus leaf effect. Instead, we show that the apparent hydrophobicity is related to contact line pinning at the pillar edges, giving a strong dependence of wetting hysteresis on the fraction of the contact line pinned on pillars. Simulating the contact line pinning on these surfaces showed similar behavior to our measurements, revealing both strong pinning at the edges of the pillars as well as mechanistic details.
Polymeric nanoneedle arrays mediate stiffness-independent intracellular delivery
Publisher: Wiley
Date: 09-2022
Abstract: Tunable vertically aligned nanostructures, usually fabricated using inorganic materials, are powerful nanoscale tools for advanced cellular manipulation. However, nanoscale precision typically requires advanced nanofabrication machinery and involves high manufacturing costs. By contrast, polymeric nanoneedles (NNs) of precise geometry can be produced by replica molding or nanoimprint lithography—rapid, simple, and cost‐effective. Here, cytocompatible polymeric arrays of NNs are engineered with identical topographies but differing stiffness, using polystyrene (PS), SU8, and polydimethylsiloxane (PDMS). By interfacing the polymeric NN arrays with adherent and suspension mammalian cells, and comparing the cellular responses of each of the three polymeric substrates, the influence of substrate stiffness from topography on cell behavior is decoupled. Notably, the ability of PS, SU8, and PDMS NNs is demonstrated to facilitate mRNA delivery to GPE86 cells with 26.8% ± 3.5%, 33.2% ± 7.4%, and 30.1% ± 4.1% average transfection efficiencies, respectively. Electron microscopy reveals the intricacy of the cell–NN interactions and immunofluorescence imaging demonstrates that enhanced endocytosis is one of the mechanisms of PS NN‐mediated intracellular delivery, involving the endocytic proteins caveolin‐1 and clathrin heavy chain. The results provide insights into the interfacial interactions between cells and polymeric NNs, and their related intracellular delivery mechanisms.
Related Organisations
SA Node Of The Australian National Fabrication Facility (ANFF-SA)
Location: Australia
SA Node Of The Australian National Fabrication Facility
Location: Australia
Max-Planck Institute For Dynamics And Self-Organisation
Location: Germany
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