ORCID Profile
0000-0002-5472-232X
Current Organisation
University of Queensland
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Microfluidics and nanofluidics | Fluid mechanics and thermal engineering | Additive manufacturing | Manufacturing engineering | Microelectromechanical systems (MEMS) | Composite and hybrid materials
Publisher: American Society of Mechanical Engineers
Date: 04-01-2016
Abstract: Plasma is a host of various analytes such as proteins, metabolites, circulating nucleic acids (CNAs), pathogens. The key process of plasma extraction is to eliminate the contamination from blood cells. Conventional methods, such as centrifugation and membrane filtration, are generally lab-intensive, time consuming and even dangerous. In this study, we report an integrated microfluidic device that combines inertial microfluidics and membrane filter. The integrated microfluidic device was evaluated by the diluted (x1/10, x1/20) whole blood, and the quality of the extracted blood plasma was tested. It was found that quality of extracted blood plasma from integrated device was equivalent to that obtained by the centrifugation. This study demonstrates a significant progress towards the practical application of inertial microfluidics with membrane filter for high-throughput and high efficient blood plasma extraction.
Publisher: AIP Publishing
Date: 07-2015
DOI: 10.1063/1.4927494
Abstract: In this paper, 3D particle focusing in a straight channel with asymmetrical expansion–contraction cavity arrays (ECCA channel) is achieved by exploiting the dean-flow-coupled elasto-inertial effects. First, the mechanism of particle focusing in both Newtonian and non-Newtonian fluids was introduced. Then particle focusing was demonstrated experimentally in this channel with Newtonian and non-Newtonian fluids using three different sized particles (3.2 μm, 4.8 μm, and 13 μm), respectively. Also, the effects of dean flow (or secondary flow) induced by expansion–contraction cavity arrays were highlighted by comparing the particle distributions in a single straight rectangular channel with that in the ECCA channel. Finally, the influences of flow rates and distances from the inlet on focusing performance in the ECCA channel were studied. The results show that in the ECCA channel particles are focused on the cavity side in Newtonian fluid due to the synthesis effects of inertial and dean-drag force, whereas the particles are focused on the opposite cavity side in non-Newtonian fluid due to the addition of viscoelastic force. Compared with the focusing performance in Newtonian fluid, the particles are more easily and better focused in non-Newtonian fluid. Besides, the Dean flow in visco-elastic fluid in the ECCA channel improves the particle focusing performance compared with that in a straight channel. A further advantage is three-dimensional (3D) particle focusing that in non-Newtonian fluid is realized according to the lateral side view of the channel while only two-dimensional (2D) particle focusing can be achieved in Newtonian fluid. Conclusively, this novel Dean-flow-coupled elasto-inertial microfluidic device could offer a continuous, sheathless, and high throughput (& 000 s−1) 3D focusing performance, which may be valuable in various applications from high speed flow cytometry to cell counting, sorting, and analysis.
Publisher: MDPI AG
Date: 23-04-2023
DOI: 10.3390/MI14050915
Abstract: Microfluidic microparticle manipulation is currently widely used in environmental, bio-chemical, and medical applications. Previously we proposed a straight microchannel with additional triangular cavity arrays to manipulate microparticles with inertial microfluidic forces, and experimentally explored the performances within different viscoelastic fluids. However, the mechanism remained poorly understood, which limited the exploration of the optimal design and standard operation strategies. In this study, we built a simple but robust numerical model to reveal the mechanisms of microparticle lateral migration in such microchannels. The numerical model was validated by our experimental results with good agreement. Furthermore, the force fields under different viscoelastic fluids and flow rates were carried out for quantitative analysis. The mechanism of microparticle lateral migration was revealed and is discussed regarding the dominant microfluidic forces, including drag force, inertial lift force, and elastic force. The findings of this study can help to better understand the different performances of microparticle migration under different fluid environments and complex boundary conditions.
Publisher: Elsevier BV
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 23-01-2017
DOI: 10.1038/SREP41153
Abstract: Sheathless particle focusing which utilises the secondary flow with a high throughput has great potential for use in microfluidic applications. In this work, an innovative particle focusing method was proposed. This method makes use of a mechanism that takes advantage of secondary flow and inertial migration. The device was a straight channel with arrays of arc-shaped grooves on the top surface. First, the mechanism and expected focusing phenomenon are explained using numerical simulation of the flow field and force balance. A simulation of particle trajectories was conducted as a reference, and then a series of experiments was designed and the effects of changes in particle size, flow rate and quantity of the groove structure were discussed. The microscopic images show that this particle focusing method performed well for different size particles, and the results agreed well with the theory and simulated results. Finally, the channel successfully concentrated Jurkat cells, which showed a good compatibility in the biological assay field. In this work, the arc-shaped groove channel was demonstrated to have the ability to achieve high-throughput, sheathless and three-dimensional particle focusing with simple operations.
Publisher: Wiley
Date: 06-2016
Abstract: In this work, particle lateral migration in s le-sheath flow of viscoelastic fluid and Newtonian fluid was experimentally investigated. The 4.8-μm micro-particles were dispersed in a polyethylene oxide (PEO) viscoelastic solution, and then the solution was injected into a straight rectangular channel with a deionised (DI) water Newtonian sheath flow. Micro-particles suspended in PEO solution migrated laterally to a DI water stream, but migration in the opposite direction from a DI water stream to a PEO solution stream or from one DI water stream to another DI water stream could not be achieved. The lateral migration of particles depends on the viscoelastic properties of the s le fluids. Furthermore, the effects of channel length, flow rate, and PEO concentration were studied. By using viscoelastic s le flow and Newtonian sheath flow, a selective particle lateral migration can be achieved in a simple straight channel, without any external force fields. This particle lateral migration technique could be potentially used in solution exchange fields such as automated cell staining and washing in microfluidic platforms, and holds numerous biomedical applications.
Publisher: Wiley
Date: 27-10-2017
Abstract: Microfluidics, which is classified as either active or passive, is capable of separating cells of interest from a complex and heterogeneous s le. Active methods utilise external fields such as electric, magnetic, acoustic, and optical to drive cells for separation, while passive methods utilise channel structures, intrinsic hydrodynamic forces, and steric hindrances to manipulate cells. However, when processing complex biological s les such as whole blood with rare cells, separation with a single module microfluidic device is difficult. Hybrid microfluidics is an emerging technique, which utilises active and passive methods whilst fulfilling higher requirements for stable performance, versatility, and convenience, including (i) the ability to process multi-target cells, (ii) enhanced ability for multiplexed separation, (iii) higher sensitivity, and (iv) tunability for a wider operational range. This review introduces the fundamental physics and typical formats for subclasses of hybrid microfluidic devices based on their different physical fields presents current ex les of cell sorting to highlight the advantage and usefulness of hybrid microfluidics on biomedicine, and then discusses the challenges and perspective of future development and the promising direction of research in this field.
Publisher: AIP Publishing
Date: 21-11-2016
DOI: 10.1063/1.4968835
Abstract: The separation of target objects conjugated with magnetic particles is a significant application in biomedicine and clinical diagnosis. Conventional magnetophoresis-based devices use a sheath flow to pre-focus the particles into a single stream and typically operate at a low flow rate. We demonstrate in this work a high-throughput, sheathless, magnetophoretic separation of magnetic and non-magnetic beads in a groove-based channel, and also report on an interesting phenomenon where the same magnetic beads in the same microchannel, but with different setups, has a different particle tracing a binary mixture of magnetic and non-magnetic beads in a diluted ferrofluid, is then fed into the channel. These magnetic beads are focused near the centreline of the channel by exploiting positive magnetophoresis and microvortices generated by grooves, whereas the non-magnetic beads are focused along the sidewalls of the channel by negative magnetophoresis and hydrophoresis. These magnetic and non-magnetic beads are separated in a wide range of flow rates (up to 80 μl min−1).
Publisher: Springer Science and Business Media LLC
Date: 21-02-2019
Publisher: Wiley
Date: 02-09-2021
Abstract: Microfluidic particle focusing has been a vital prerequisite step in s le preparation for downstream particle separation, counting, detection, or analysis, and has attracted broad applications in biomedical and chemical areas. Besides all the active and passive focusing methods in Newtonian fluids, particle focusing in viscoelastic fluids has been attracting increasing interest because of its advantages induced by intrinsic fluid property. However, to achieve a well‐defined focusing position, there is a need to extend channel lengths when focusing micrometer‐sized or sub‐microsized particles, which would result in the size increase of the microfluidic devices. This work investigated the sheathless viscoelastic focusing of particles and cells in a zigzag microfluidic channel. Benefit from the zigzag structure of the channel, the channel length and the footprint of the device can be reduced without sacrificing the focusing performance. In this work, the viscoelastic focusing, including the focusing of 10 μm polystyrene particles, 5 μm polystyrene particles, 5 μm magnetic particles, white blood cells (WBCs), red blood cells (RBCs), and cancer cells, were all demonstrated. Moreover, magnetophoretic separation of magnetic and nonmagnetic particles after viscoelastic pre‐focusing was shown. This focusing technique has the potential to be used in a range of biomedical applications.
Publisher: Elsevier BV
Date: 12-2021
Publisher: American Chemical Society (ACS)
Date: 23-01-2019
DOI: 10.1021/ACS.ANALCHEM.8B05712
Abstract: Focusing and separation of particles such as cells at high throughput is extremely attractive for biomedical applications. Particle manipulation based on inertial effects requires a high flow speed and thus is well-suited to high-throughput applications. Recently, inertial focusing and separation using curvilinear microchannels has been attracting a great amount of interest because of the linear structure for parallelization, small device footprint, superior particle-focusing performance, and easy implementation of particle separation. However, the curvature directions of these microchannels alternate, leading to variations in both the magnitude and direction of the induced secondary flow. Accumulation of this variation along the channel causes unpredictable behaviors of particles. This paper systematically investigates the inertial-focusing phenomenon in low-aspect-ratio symmetric sinusoidal channels. First, we comprehensively studied the effects of parameters such as viscosity, flow conditions, particle size, and geometric dimensions of the microchannel on differential particle focusing. We found that particle inertial focusing is generally independent of fluid kinematic viscosity but highly dependent on particle size, flow conditions, and channel dimensions. Next, we derived an explicit scaling factor and included all four dimensionless parameters (particle-blockage ratio, curvature ratio, Dean number, and channel aspect ratio) in a single operational map to illustrate the particle-focusing patterns. Finally, we proposed a rational guideline to intuitively instruct the design of channel dimensions for separation of a given particle mixture.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6LC01007E
Abstract: We proposed and developed a novel viscoelastic ferrofluid, and demonstrated its superior advantages for continuous sheathless separation of nonmagnetic particles.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8LC00047F
Abstract: In this work, we proposed an amalgamation-assisted lithography technique using liquid metal alloys for the fabrication of complex channels with a simple fabrication process, room-temperature fabrication and low toxicity.
Publisher: Elsevier BV
Date: 12-2016
Publisher: Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences
Date: 2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6RA25328H
Abstract: Sheathless particle focusing and separation in viscoelastic fluid is demonstrated using an integrated ECCA (straight channel section with asymmetrical expansion–contraction cavity arrays) straight channel.
Publisher: Wiley
Date: 06-04-2018
Abstract: This work presents a simple, low-cost method to fabricate semi-circular channels using solder paste, which can amalgamate the cooper surface to form a half-cylinder mold using the surface tension of Sn-Pd alloy (the main component in solder paste). This technique enables semi-circular channels to be manufactured with different dimensions. These semi-circular channels will then be integrated with a polymethylmethacrylate frame and machine screws to create miniaturized, portable microfluidic valves for sequential liquid delivery and particle synthesis. This approach avoids complicated fabrication processes and expensive facilities and thus has the potential to be a useful tool for lab-on-a-chip applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6LC00843G
Abstract: By exploiting the Dean-flow-coupled elasto-inertial effects, continuous, sheathless, and high purity plasma extraction under viscoelastic fluid in a straight channel with asymmetrical expansion–contraction cavity arrays (ECCA channel) is demonstrated.
Publisher: American Chemical Society (ACS)
Date: 29-04-2021
Publisher: MDPI AG
Date: 22-06-2017
DOI: 10.3390/MI8070197
Publisher: Elsevier BV
Date: 07-2019
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2017
Publisher: MDPI AG
Date: 25-10-2017
DOI: 10.3390/MI8110315
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7LC01076A
Abstract: In this review, we discuss the up-to-date progress of particle migration in viscoelastic fluids mainly from the aspect of applications, laying out a comprehensive perspective on their potential in future lab-on-a-chip platforms.
Publisher: American Chemical Society (ACS)
Date: 08-12-2020
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2017
Publisher: AIP Publishing
Date: 15-04-2019
DOI: 10.1063/1.5086376
Abstract: Microdroplets of gallium-based liquid metal alloys have enabled various applications in the fields of biomedicine, electronics, and chemistry. However, due to the high surface tension of liquid metal, high-throughput production of uniformly sized liquid metal microdroplets is challenging using conventional acoustic or microfluidic methods. Here, adapting the submerged electrodispersion technique that has conventionally been used for generating water-based microdroplets, we develop a simple and straightforward platform for the high-throughput production of near-monodisperse (coefficient of variation less than 5%) liquid metal microdroplets in oil without using microfluidic devices. We demonstrate the capabilities of this method for producing liquid metal microdroplets (diameters ranging from tens to hundreds of micrometers) and introduce a spinning disk to induce a flow of oil phase for preventing the coalescence of the microdroplets. The simplicity and remarkable abilities demonstrated for this method may pave the path for the development of future innovative applications based on liquid metal microdroplets.
Publisher: SPIE
Date: 10-10-2013
DOI: 10.1117/12.2035924
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2LC00856D
Abstract: Heterogeneous clusters of cancer cells and leukocytes in blood were visualized by combining high-throughput and high-sensitivity fluorescence imaging flow cytometry with 5-aminolevulinic acid stimulation.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0LC00080A
Abstract: The upgraded version of intelligent image-activated cell sorting (iIACS) has enabled higher-throughput and more sensitive intelligent image-based sorting of single live cells from heterogeneous populations.
Publisher: Springer Science and Business Media LLC
Date: 19-12-2019
Publisher: MDPI AG
Date: 28-04-2020
DOI: 10.3390/MI11050461
Abstract: Inertial microfluidic technology, which can manipulate the target particle entirely relying on the microchannel characteristic geometry and intrinsic hydrodynamic effect, has attracted great attention due to its fascinating advantages of high throughput, simplicity, high resolution and low cost. As a passive microfluidic technology, inertial microfluidics can precisely focus, separate, mix or trap target particles in a continuous and high-flow-speed manner without any extra external force field. Therefore, it is promising and has great potential for a wide range of industrial, biomedical and clinical applications. In the regime of inertial microfluidics, particle migration due to inertial effects forms multiple equilibrium positions in straight channels. However, this is not promising for particle detection and separation. Secondary flow, which is a relatively minor flow perpendicular to the primary flow, may reduce the number of equilibrium positions as well as modify the location of particles focusing within channel cross sections by applying an additional hydrodynamic drag. For secondary flow, the pattern and magnitude can be controlled by the well-designed channel structure, such as curvature or disturbance obstacle. The magnitude and form of generated secondary flow are greatly dependent on the disturbing microstructure. Therefore, many inventive and delicate applications of secondary flow in inertial microfluidics have been reported. In this review, we comprehensively summarize the usage of the secondary flow in inertial microfluidics.
Publisher: Springer Science and Business Media LLC
Date: 21-03-2019
DOI: 10.1038/S41467-019-09325-4
Abstract: Conductive elastic composites have been used widely in soft electronics and soft robotics. These composites are typically a mixture of conductive fillers within elastomeric substrates. They can sense strain via changes in resistance resulting from separation of the fillers during elongation. Thus, most elastic composites exhibit a negative piezoconductive effect, i.e. the conductivity decreases under tensile strain. This property is undesirable for stretchable conductors since such composites may become less conductive during deformation. Here, we report a liquid metal-filled magnetorheological elastomer comprising a hybrid of fillers of liquid metal microdroplets and metallic magnetic microparticles. The composite’s resistivity reaches a maximum value in the relaxed state and drops drastically under any deformation, indicating that the composite exhibits an unconventional positive piezoconductive effect. We further investigate the magnetic field-responsive thermal properties of the composite and demonstrate several proof-of-concept applications. This composite has prospective applications in sensors, stretchable conductors, and responsive thermal interfaces.
Publisher: Wiley
Date: 26-10-2019
Publisher: MDPI AG
Date: 11-2016
DOI: 10.3390/MI7110195
Publisher: Wiley
Date: 22-01-2018
Abstract: Proteinuria is an established risk marker for progressive renal function loss and patients would significantly benefit from a point-of-care testing. Although extensive work has been done to develop the microfluidic devices for the detection of urinary protein, they need the complicated operation and bulky peripherals. Here, we present a rapid, maskless 3D prototyping for fabrication of capillary fluidic circuits using laser engraving. The capillary circuits can be fabricated in a short amount of time (<10 min) without the requirements of clean-room facilities and photomasks. The advanced capillary components (e.g., trigger valves, retention valves and retention bursting valves) were fabricated, enabling the sequential liquid delivery and s le-reagent mixing. With the integration of smartphone-based detection platform, the microfluidic device can quantify the urinary protein via a colorimetric analysis. By eliminating the bulky and expensive equipment, this smartphone-based detection platform is portable for on-site quantitative detection.
Publisher: Wiley
Date: 17-01-2023
Abstract: 3D printing provides access to complex multilevel architectures, though the capability to routinely print and integrate structures of controlled porosity is limited. Herein, grayscale digital light projection 3D printing of a polymerization‐induced phase separation ink is introduced to directly 3D print functionally graded porous within a single layer from the same ink formulation. The structural properties of materials printed from a single ink are tuned from an effectively dense to a porous material with interconnected pores up to 250 nm. Heterostructures with the physically dense structure of porosity 0.8% and porous structures with up to 23% can be concurrently formed within a layer, with high spatial resolution inherent of this 3D printing technique. Materials with densities from 1.01 to 1.21 g cm −3 are 3D printed in a wicking device and show wicking rates (H 2 O) from complete diffusion blockage up to 4.5 mm h −1 . Furthermore, a proof‐of‐concept membrane‐integrated fluidic device is used for the elemental metal sensing of iron in soil. The presented single‐step fabrication of functionally graded materials with pixel‐based control within a single layer holds potential for manufacturing and integrating membranes or sorbents for environmental, biotechnology, and healthcare applications.
Publisher: Elsevier BV
Date: 09-2023
Publisher: Springer Science and Business Media LLC
Date: 03-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2NR07178A
Abstract: 3D printed functionally integrated device containing nanoporous membranes with properties tailored for the electroextraction of DNA.
Publisher: American Chemical Society (ACS)
Date: 25-06-2020
Publisher: Wiley
Date: 22-04-2018
Abstract: Functional nanoparticles comprised of liquid metals, such as eutectic gallium indium (EGaIn) and Galinstan, present exciting opportunities in the fields of flexible electronics, sensors, catalysts, and drug delivery systems. Methods used currently for producing liquid metal nanoparticles have significant disadvantages as they rely on both bulky and expensive high-power sonication probe systems, and also generally require the use of small molecules bearing thiol groups to stabilize the nanoparticles. Herein, an innovative microfluidics-enabled platform is described as an inexpensive, easily accessible method for the on-chip mass production of EGaIn nanoparticles with tunable size distributions in an aqueous medium. A novel nanoparticle-stabilization approach is reported using brushed polyethylene glycol chains with trithiocarbonate end-groups negating the requirements for thiol additives while imparting a "stealth" surface layer. Furthermore, a surface modification of the nanoparticles is demonstrated using galvanic replacement and conjugation with antibodies. It is envisioned that the demonstrated microfluidic technique can be used as an economic and versatile platform for the rapid production of liquid metal-based nanoparticles for a range of biomedical applications.
Publisher: American Chemical Society (ACS)
Date: 09-08-2021
Publisher: Elsevier BV
Date: 2020
DOI: 10.2139/SSRN.3554082
Publisher: Wiley
Date: 19-12-2018
Publisher: IOP Publishing
Date: 22-07-2015
Publisher: American Chemical Society (ACS)
Date: 12-02-2019
DOI: 10.1021/ACS.ANALCHEM.9B00093
Abstract: Although droplet-based microfluidics has been broadly used as a versatile tool in biology, chemistry, and nanotechnology, its rather complicated microfabrication process and the requirement of specialized hardware and operating skills hinder researchers fully unleashing the potential of this powerful platform. Here, we develop an integrated microdroplet generator enabled by a spinning conical frustum for the versatile production of near-monodisperse microdroplets in a high-throughput and off-chip manner. The construction and operation of this generator are simple and straightforward without the need of microfabrication, and we demonstrate that the generator is able to passively and actively control the size of the produced microdroplets. In addition to water microdroplets, this generator can produce microdroplets of liquid metal that would be difficult to produce in conventional microfluidic platforms as liquid metal has high surface tension. Moreover, we demonstrate that this generator can produce solid hydrogel microparticles and fibers using integrated ultraviolet (UV) light. In the end, we further explore the ability of this generator for forming double emulsions by coflowing two immiscible liquids. Given the remarkable abilities demonstrated by this platform and the tremendous potential of microdroplets, this user-friendly method may revolutionize the future of droplet-based chemical synthesis and biological analysis.
Publisher: AIP Publishing
Date: 05-2016
DOI: 10.1063/1.4949770
Abstract: While neurons and glial cells both play significant roles in the development and therapy of schizophrenia, their specific contributions are difficult to differentiate because the methods used to separate neurons and glial cells are ineffective and inefficient. In this study, we reported a high-throughput microfluidic platform based on the inertial microfluidic technique to rapidly and continuously separate neurons and glial cells from dissected brain tissues. The optimal working condition for an inertial biochip was investigated and evaluated by measuring its separation under different flow rates. Purified and enriched neurons in a primary neuron culture were verified by confocal immunofluorescence imaging, and neurons performed neurite growth after separation, indicating the feasibility and biocompatibility of an inertial separation. Phencyclidine disturbed the neuroplasticity and neuron metabolism in the separated and the unseparated neurons, with no significant difference. Apart from isolating the neurons, purified and enriched viable glial cells were collected simultaneously. This work demonstrates that an inertial microchip can provide a label-free, high throughput, and harmless tool to separate neurological primary cells.
Publisher: American Chemical Society (ACS)
Date: 17-08-2017
DOI: 10.1021/ACS.ANALCHEM.7B02671
Abstract: This work investigates the on-chip washing process of microparticles and cells using coflow configuration of viscoelastic fluid and Newtonian fluid in a straight microchannel. By adding a small amount of biocompatible polymers into the particle medium or cell culture medium, the induced viscoelasticity can push particles and cells laterally from their original medium to the coflow Newtonian medium. This behavior can be used for particle or cell washing. First, we demonstrated on-chip particle washing by the size-dependent migration speed using coflow of viscoelastic fluid and Newtonian fluid. The critical particle size for efficient particle washing was determined. Second, we demonstrated continuous on-chip washing of Jurkat cells using coflow of viscoelastic fluid and Newtonian fluid. The lateral migration process of Jurkat cells along the channel length was investigated. In addition, the cell washing quality was verified by hemocytometry and flow cytometry with a recovery rate as high as 92.8%. Scanning spectrophotometric measurements of the media from the two inlets and the two outlets demonstrated that diffusion of the coflow was negligible, indicating efficient cell washing from culture medium to phosphate-buffered saline medium. This technique may be a safer, simpler, cheaper, and more efficient alternative to the tedious conventional centrifugation methods and may open up a wide range of biomedical applications.
Publisher: AIP Publishing
Date: 12-2022
DOI: 10.1063/5.0129764
Abstract: Microfluidic technologies have been developed for decades, especially in bio-chemical research and applications. Among them, sheath flow is one of the most well-known techniques used for focusing microparticles into extremely narrow widths. With varying Reynolds numbers, sheath flow displays different behaviors, including diffusion, stable thread, and turbulence. In this study, a previously unknown phenomenon, namely, stable expansion, is originally reported in a 200 × 70 μm microchannel with a Reynolds number ranging from ∼10 to ∼110. This stable expansion of focusing width differs from all the reported phenomena in the literature and is experimentally explored in this study. First, the phenomenon is introduced, identified, and comprehensively described using different experimental s les and methods. Subsequently, an image processing algorithm of post-analysis is proposed and calibrated by the theoretical results of stable thread. Based on the calibrated standard protocol, the effects of flow rates and a hysteresis phenomenon due to variation in the flow rate are revealed and studied. In addition, the effects of fluid viscosity are investigated by introducing a mixture of deionized (DI) water and glycerin. It is found that, in this 200 × 70 μm2 (weight × height) microchannel made of PDMS, the stable expansion phenomenon will occur when the Reynolds number exceeds 10, and the expanded width will increase with total flow rate. Moreover, it is found that the expanded width in a flow rate reducing route is displayed to be wider than that in an increasing route. On the other hand, a high viscosity contrast (& ) between the middle s le and sheath flows can eliminate the focusing width expansion. The results indicate that this originally revealed phenomenon is experimentally repeatable and worth further studying to help researchers better understand the mechanism of microfluidics.
Publisher: Elsevier BV
Date: 08-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0LC00939C
Abstract: An integrated revolving needle emulsion generator (RNEG) is developed to achieve high-throughput production of monodispersed droplets in an off-chip manner.
Publisher: Springer Science and Business Media LLC
Date: 12-12-2018
Publisher: ASME International
Date: 23-02-2017
DOI: 10.1115/1.4035588
Abstract: Plasma is a host of numerous analytes such as proteins, metabolites, circulating nucleic acids (CNAs), and pathogens, and it contains massive information about the functioning of the whole body, which is of great importance for the clinical diagnosis. Plasma needs to be completely cell-free for effective detection of these analytes. The key process of plasma extraction is to eliminate the contamination from blood cells. Centrifugation, a golden standard method for blood separation, is generally lab-intensive, time consuming, and even dangerous to some extent, and needs to be operated by well-trained staffs. Membrane filtration can filter cells very effectively according to its pore size, but it is prone to clogging by dense particle concentration and suffers from limited capacity of filtration. Frequent rinse is lab-intensive and undesirable. In this work, we proposed and fabricated an integrated microfluidic device that combined particle inertial focusing and membrane filter for high efficient blood plasma separation. The integrated microfluidic device was evaluated by the diluted (×1/10, ×1/20) whole blood, and the quality of the extracted blood plasma was measured and compared with that from the standard centrifugation. We found that the quality of the extracted blood plasma from the proposed device can be equivalent to that from the standard centrifugation. This study demonstrates a significant progress toward the practical application of inertial microfluidics with membrane filter for high-throughput and highly efficient blood plasma extraction.
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: Elsevier BV
Date: 2024
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9LC00482C
Abstract: Microalgae cells have been recognized as a promising sustainable resource to meet worldwide growing demands for renewable energy, food, livestock feed, water, cosmetics, pharmaceuticals, and materials. In order to ensure high-efficiency and high-quality production of biomass, biofuel, or bio-based products, purification procedures prior to the storage and cultivation of the microalgae from contaminated bacteria are of great importance. The present work proposed and developed a simple, sheathless, and efficient method to separate microalgae Chlorella from bacteria Bacillus Subtilis in a straight channel using the viscoelasticity of the medium. Microalgae and bacteria migrate to different lateral positions closer to the channel centre and channel walls respectively. Fluorescent microparticles with 1 μm and 5 μm diameters were first used to mimic the behaviours of bacteria and microalgae to optimize the separating conditions. Subsequently, size-based separation in Newtonian fluid and in viscoelastic fluid in straight channels with different aspect ratios was compared and demonstrated. Under the optimal condition, the removal ratio for 1 μm microparticles and separation efficiency for 5 μm particles can reach up to 98.28% and 93.85% respectively. For bacteria and microalgae cells separation, the removal ratio for bacteria and separation efficiency for microalgae cells is 92.69% and 100% respectively. This work demonstrated the continuous and sheathless separation of microalgae from bacteria for the first time by viscoelastic microfluidics. This technique can also be applied as an efficient and user-friendly method to separate mammalian cells or other kinds of cells.
Publisher: Springer Science and Business Media LLC
Date: 23-02-2018
DOI: 10.1007/S10544-018-0269-5
Abstract: In this work, a novel double-layer microfluidic device for enhancing particle focusing was presented. The double-layer device consists of a channel with expansion-contraction array and periodical slanted grooves. The secondary flows induced by the grooves modulate the flow patterns in the expansion-contraction-array (ECA) channel, further affecting the particle migration. Compared with the single ECA channel, the double-layer channel can focus the particles over a wider range of flow rate. Due to the differentiation of lateral migration, the double-layer channel is able to distinguish the particles with different sizes. Furthermore, the equilibrium positions could be modulated by the orientation of grooves. This work demonstrates the possibility to enhance and adjust the inertial focusing in an ECA channel with the assistance of grooves, which may provide a simple and portable platform for downstream filtration, separation, and detection.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5LC01159K
Abstract: We provide a comprehensive review describing the fundamental mechanisms of inertial microfluidics, structure design and applications in biology, medicine and industry.
Publisher: SPIE
Date: 26-01-2016
DOI: 10.1117/12.2211265
Start Date: 2024
End Date: 12-2026
Amount: $414,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2023
End Date: 12-2023
Amount: $731,584.00
Funder: Australian Research Council
View Funded Activity