ORCID Profile
0000-0001-7450-6205
Current Organisation
University of New South Wales
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Microbial genetics | Microbial Genetics | Biomedical Instrumentation | Synthetic biology | Genetics | Mechanical Engineering | Genomics | Microelectromechanical Systems (MEMS)
Expanding Knowledge in the Biological Sciences | Expanding Knowledge in Technology |
Publisher: SPIE-Intl Soc Optical Eng
Date: 23-07-2014
Publisher: SPIE
Date: 21-03-2016
DOI: 10.1117/12.2213149
Publisher: IOP Publishing
Date: 24-07-2013
Publisher: The Optical Society
Date: 19-02-2015
DOI: 10.1364/BOE.6.000849
Publisher: Springer Science and Business Media LLC
Date: 27-05-2014
DOI: 10.1038/SREP05060
Publisher: Springer Science and Business Media LLC
Date: 21-02-2019
Publisher: SPIE-Intl Soc Optical Eng
Date: 07-05-2014
Publisher: Wiley
Date: 10-07-2021
Abstract: Magnetic Digital microfluidics (DMF), which enables the manipulation of droplets containing different types of s les and reagents by permanent magnets or electromagnet arrays, has been used as a promising platform technology for bioanalytical and preparative assays. This is due to its unique advantages such as simple and “power free” operation, easy assembly, great compatibility with auto control systems, and dual functionality of magnetic particles (actuation and target attachment). Over the past decades, magnetic DMF technique has gained a widespread attention in many fields such as s le‐to‐answer molecular diagnostics, immunoassays, cell assays, on‐demand chemical synthesis, and single‐cell manipulation. In the first part of this review, we summarised features of magnetic DMF. Then, we introduced the actuation mechanisms and fabrication of magnetic DMF. Furthermore, we discussed five main applications of magnetic DMF, namely drug screening, protein assays, polymerase chain reaction (PCR), cell manipulation, and chemical analysis and synthesis. In the last part of the review, current challenges and limitations with magnetic DMF technique were discussed, such as biocompatibility, automation of microdroplet control systems, and microdroplet evaporation, with an eye on towards future development.
Publisher: IEEE
Date: 07-2013
Publisher: Springer Science and Business Media LLC
Date: 07-2018
DOI: 10.1038/S41596-018-0008-7
Abstract: The ability to rapidly assay morphological and intracellular molecular variations within large heterogeneous populations of cells is essential for understanding and exploiting cellular heterogeneity. Optofluidic time-stretch microscopy is a powerful method for meeting this goal, as it enables high-throughput imaging flow cytometry for large-scale single-cell analysis of various cell types ranging from human blood to algae, enabling a unique class of biological, medical, pharmaceutical, and green energy applications. Here, we describe how to perform high-throughput imaging flow cytometry by optofluidic time-stretch microscopy. Specifically, this protocol provides step-by-step instructions on how to build an optical time-stretch microscope and a cell-focusing microfluidic device for optofluidic time-stretch microscopy, use it for high-throughput single-cell image acquisition with sub-micrometer resolution at >10,000 cells per s, conduct image construction and enhancement, perform image analysis for large-scale single-cell analysis, and use computational tools such as compressive sensing and machine learning for handling the cellular 'big data'. Assuming all components are readily available, a research team of three to four members with an intermediate level of experience with optics, electronics, microfluidics, digital signal processing, and s le preparation can complete this protocol in a time frame of 1 month.
Publisher: Elsevier BV
Date: 12-2020
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4812140
Publisher: Elsevier BV
Date: 12-2021
Publisher: American Chemical Society (ACS)
Date: 19-01-2023
Publisher: American Chemical Society (ACS)
Date: 23-08-2018
DOI: 10.1021/ACS.ANALCHEM.8B01794
Abstract: Microalgal biofuels and biomass have ecofriendly advantages as feedstocks. Improved understanding and utilization of microalgae require large-scale analysis of the morphological and metabolic heterogeneity within populations. Here, with Euglena gracilis as a model microalgal species, we evaluate how fluorescence- and brightfield-derived-image-based descriptors vary during environmental stress at the single-cell level. This is achieved with a new multiparameter fluorescence-imaging cytometric technique that allows the assaying of thousands of cells per experiment. We track morphological changes, including the intensity and distribution of intracellular lipid droplets, and pigment autofluorescence. The combined fluorescence-morphological analysis identifies new metrics not accessible with traditional flow cytometry, including the lipid-to-cell-area ratio (LCAR), which shows promise as an indicator of oil productivity per biomass. Single-cell metrics of lipid productivity were highly correlated ( R
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8LC00568K
Abstract: We demonstrate passive, continuous, and high-throughput separation of hydrogel droplets by size using inertial microfluidics.
Publisher: IEEE
Date: 24-10-2020
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 09-2023
Publisher: Elsevier BV
Date: 07-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1LC01030A
Abstract: Single-cell cultivation is essential to investigate the actual cellular and subcellular information of in idual cells and enhance single-cell colonies and cell-derived products for further analysis at a single-cell level.
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4NR03672G
Abstract: A novel laser rapid thermal annealing (LRTA) technique is reported to tune the plasmonic resonance of disk-shaped nanoporous gold (NPG) nanoparticles for the first time.
Publisher: SPIE
Date: 09-03-2015
DOI: 10.1117/12.2078534
Publisher: IEEE
Date: 07-2013
Publisher: Springer Science and Business Media LLC
Date: 19-01-2022
DOI: 10.1038/S41378-021-00333-3
Abstract: In this study, we demonstrated the label-free continuous separation and enrichment of Bacillus subtilis populations based on length using viscoelastic microfluidics. B. subtilis , a gram-positive, rod-shaped bacterium, has been widely used as a model organism and an industrial workhorse. B. subtilis can be arranged in different morphological forms, such as single rods, chains, and clumps, which reflect differences in cell types, phases of growth, genetic variation, and changing environmental factors. The ability to prepare B. subtilis populations with a uniform length is important for basic biological studies and efficient industrial applications. Here, we systematically investigated how flow rate ratio, poly(ethylene oxide) (PEO) concentration, and channel length affected the length-based separation of B. subtilis cells. The lateral positions of B. subtilis cells with varying morphologies in a straight rectangular microchannel were found to be dependent on cell length under the co-flow of viscoelastic and Newtonian fluids. Finally, we evaluated the ability of the viscoelastic microfluidic device to separate the two groups of B. subtilis cells by length (i.e., 1–5 μm and μm) in terms of extraction purity (EP), extraction yield (EY), and enrichment factor (EF) and confirmed that the device could separate heterogeneous populations of bacteria using elasto-inertial effects.
Publisher: Springer Science and Business Media LLC
Date: 07-09-2017
DOI: 10.1038/S41598-017-10452-5
Abstract: Euglena gracilis ( E. gracilis ) has been proposed as one of the most attractive microalgae species for biodiesel and biomass production, which exhibits a number of shapes, such as spherical, spindle-shaped, and elongated. Shape is an important biomarker for E. gracilis , serving as an indicator of biological clock status, photosynthetic and respiratory capacity, cell-cycle phase, and environmental condition. The ability to prepare E. gracilis of uniform shape at high purities has significant implications for various applications in biological research and industrial processes. Here, we adopt a label-free, high-throughput, and continuous technique utilizing inertial microfluidics to separate E. gracilis by a key shape parameter-cell aspect ratio (AR). The microfluidic device consists of a straight rectangular microchannel, a gradually expanding region, and five outlets with fluidic resistors, allowing for inertial focusing and ordering, enhancement of the differences in cell lateral positions, and accurate separation, respectively. By making use of the shape-activated differences in lateral inertial focusing dynamic equilibrium positions, E. gracilis with different ARs ranging from 1 to 7 are directed to different outlets.
Publisher: SPIE
Date: 11-03-2015
DOI: 10.1117/12.2078530
Publisher: Informa UK Limited
Date: 19-01-2021
Publisher: Elsevier BV
Date: 2024
Publisher: Elsevier BV
Date: 03-2018
DOI: 10.1016/J.YMETH.2017.10.004
Abstract: Innovations in optical microscopy have opened new windows onto scientific research, industrial quality control, and medical practice over the last few decades. One of such innovations is optofluidic time-stretch quantitative phase microscopy - an emerging method for high-throughput quantitative phase imaging that builds on the interference between temporally stretched signal and reference pulses by using dispersive properties of light in both spatial and temporal domains in an interferometric configuration on a microfluidic platform. It achieves the continuous acquisition of both intensity and phase images with a high throughput of more than 10,000 particles or cells per second by overcoming speed limitations that exist in conventional quantitative phase imaging methods. Applications enabled by such capabilities are versatile and include characterization of cancer cells and microalgal cultures. In this paper, we review the principles and applications of optofluidic time-stretch quantitative phase microscopy and discuss its future perspective.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1LC00721A
Abstract: The capabilities of impedance cytometry to detect intracellular components ( i.e. , volume and distribution) are investigated, and it is found that non-uniform intracellular distribution causes the tilt tendency of high-frequency impedance pulses.
Publisher: American Chemical Society (ACS)
Date: 08-12-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2LC00339B
Abstract: A viscoelastic microfluidic device for shape-based separation of drug-treated Escherichia coli .
Publisher: Wiley
Date: 11-03-2013
Abstract: This paper presents a novel dielectrophoresis-based microfluidic device incorporating round hurdles within an S-shaped microchannel for continuous manipulation and separation of microparticles. Local nonuniform electric fields are generated due to the combined effects of obstacle and curvature, which in turn induce negative dielectrophoresis forces exerting on the particle that transport throughout the microchannel electrokinetically. Experiments were conducted to demonstrate the controlled trajectories of fix-sized (i.e. 10 or 15 μm) polystyrene particles, and size-dependent separation of 10 and 15 μm particles by adjusting the applied voltages at the inlet and outlets. Numerical simulations were also performed to predict the particle trajectories, which showed reasonable agreement with experimentally observed results. Compared to other microchannel designs that make use of either obstacle or curvature in idually for inhomogeneous electric fields, the developed microchannel offers advantages such as improved controllability of particle motion, lower requirement of applied voltage, reduced fouling, and particle adhesion, etc.
Publisher: SPIE
Date: 07-03-2016
DOI: 10.1117/12.2212573
Publisher: American Chemical Society (ACS)
Date: 12-01-2023
Publisher: Wiley
Date: 26-02-2015
Abstract: We experimentally demonstrate a label-free biosensor for the ERBB2 cancer gene DNA target based on the distance-dependent detection of surface-enhanced fluorescence (SEF) on nanoporous gold disk (NPGD) plasmonic nanoparticles. We achieve detection of 2.4 zeptomole of DNA target on the NPGD substrate with an upper concentration detection limit of 1 nM. Without the use of molecular spacers, the NPGD substrate as an SEF platform was shown to provide higher net fluorescence for visible and NIR fluorophores compared to glass and non-porous gold substrates. The enhanced fluorescence signals in patterned nanoporous gold nanoparticles make NPGD a viable material for further reducing detection limits for biomolecular targets used in clinical assays. With patterned nanoporous gold disk (NPGD) plasmonic nanoparticles, a label-free biosensor that makes use of distance-dependent detection of surface-enhanced fluorescence (SEF) is constructed and tested for zeptomole detection of ERBB2 cancer gene DNA targets.
Publisher: IOP Publishing
Date: 08-01-2014
Publisher: Elsevier BV
Date: 03-2022
Publisher: Elsevier BV
Date: 03-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1RA02636D
Abstract: This work reviews recent advances in the integration of emulsion microdroplets and flow cytometry technologies, so-called droplet flow cytometry (DFC), for high-throughput single-cell analysis.
Publisher: Wiley
Date: 21-03-2022
DOI: 10.1002/BIT.28077
Abstract: Biofilms are communities of bacterial cells encased in a self‐produced polymeric matrix and exhibit high tolerance towards environmental stress. Despite the plethora of research on biofilms, most biofilm models are produced using mono‐interface culture in static flow conditions, and knowledge of the effects of interfaces and mechanical forces on biofilm development remains fragmentary. This study elucidated the effects of air–liquid (ALI) or liquid–liquid (LLI) interfaces and mechanical shear forces induced by airflow and hydrodynamic flow on biofilm growing using a custom‐designed dual‐channel microfluidic platform. Results from this study showed that comparing biofilms developed under continuous nutrient supply and shear stresses free condition to those developed with limited nutrient supply, ALI biofilms were four times thicker, 60% less permeable, and 100 times more resistant to antibiotics, while LLI biofilms were two times thicker, 20% less permeable, and 100 times more resistant to antibiotics. Subjecting the biofilms to mechanical shear stresses affected the biofilm structure across the biofilm thickness significantly, resulting in generally thinner and denser biofilm compared to their controlled biofilm cultured in the absence of shear stresses, and the ALI and LLI biofilm's morphology was vastly different. Biofilms developed under hydrodynamic shear stress also showed increased antibiotic resistance. These findings highlight the importance of investigating biofilm growth and its mechanisms in realistic environmental conditions and demonstrate a feasible approach to undertake this study using a novel platform.
Publisher: American Chemical Society (ACS)
Date: 17-07-2023
Publisher: Wiley
Date: 31-07-2023
Abstract: Biofilms are structured communities of bacterial cells encased in a self‐produced polymeric matrix, which develop over time and exhibit temporal responses to stimuli from internal biological processes or external environmental changes. They can be detrimental, threatening public health and causing economic loss, while they also play beneficial roles in ecosystem health, biotechnology processes, and industrial settings. Biofilms express extreme heterogeneity in their physical properties and structural composition, resulting in critical challenges in understanding them comprehensively. The lack of detailed knowledge of biofilms and their phenotypes has deterred significant progress in developing strategies to control their negative impacts and take advantage of their beneficial applications. A range of in vitro models and characterization tools have been developed and used to study biofilm growth and, specifically, to investigate the impact of environmental and growth factors on their development. This review article discusses the existing knowledge of biofilm properties and explains how external factors, such as flow condition, surface, interface, and host factor, may impact biofilm growth. The limitations of current tools, techniques, and in vitro models that are currently used for biofilms are also presented.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4TC02328E
Abstract: We report a surface modification protocol to control nanoporous gold (NPG) disk morphology and tune its plasmonic resonance.
Publisher: Springer Science and Business Media LLC
Date: 03-12-2011
Publisher: MDPI AG
Date: 26-03-2019
DOI: 10.3390/MI10030209
Abstract: Gallium-based liquid metal alloys have been attracting attention from both industry and academia as soft, deformable, reconfigurable and multifunctional materials in microfluidic, electronic and electromagnetic devices. Although various technologies have been explored to control the morphology of liquid metals, there is still a lack of methods that can achieve precise morphological control over a free-standing liquid metal droplet without the use of mechanical confinement. Electrochemical manipulation can be relatively easy to apply to liquid metals, but there is a need for techniques that can enable automatic and precise control. Here, we investigate the use of an electrochemical technique combined with a feedback control system to automatically and precisely control the morphology of a free-standing liquid metal droplet in a sodium hydroxide solution. We establish a proof-of-concept platform controlled by a microcontroller to demonstrate the reconfiguration of a liquid metal droplet to desired patterns. We expect that this method will be further developed to realize future reconfigurable liquid metal-enabled soft robots.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3LC00237C
Abstract: We optimized the microfluidic chip of imaging flow cytometry by setting horizontal connections By OTS microscopy, cells can be imaged at 40 m s −1 in our device.
Publisher: American Scientific Publishers
Date: 04-2012
Abstract: Sorting of particles such as cells is a critical process for many biomedical applications, and it is challenging to integrate it into an analytical microdevice. We report an effective and flexible dielectrophoresis (DEP)-based microfluidic device for continuous sorting of multiple particles in a microchannel. The particle sorter is composed of two components-a DEP focusing unit and a Movable DEP Trap (MDT). The trap is formed by an array of microelectrodes at the bottom of the channel and a transparent electrode plate placed at the top. The location of the trap is dependent on the configuration of voltages on the array and therefore is addressable. Flowing particles are first directed and focused into a single particle stream by the focusing unit. The streamed particles are then sorted into different fractions using the movable trap by rapidly switching the applied voltage. The performance of the sorter is demonstrated by successfully sorting microparticles in a continuous flow. The proposed DEP-based microfluidic sorter can be implemented in applications such as s le preparation and cell sorting for subsequent analytical processing, where sorting of particles is needed.
Publisher: Elsevier BV
Date: 04-2023
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: Elsevier BV
Date: 03-2022
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-01-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6LC01118G
Abstract: We study the behaviors of ellipsoidal microalgal cells with varying aspect ratios using inertial microfluidics for biofuels and environmental applications.
Publisher: Springer Science and Business Media LLC
Date: 23-06-2020
DOI: 10.1038/S41598-020-67208-X
Abstract: Chlamydia infection and disease are endemic in free-ranging koalas. Antibiotics remain the front line treatment for Chlamydia in koalas, despite their rates of treatment failure and adverse gut dysbiosis outcomes. A Chlamydia vaccine for koalas has shown promise for replacing antibiotic treatment in mild ocular Chlamydia disease. In more severe disease presentations that require antibiotic intervention, the effect of vaccinating during antibiotic use is not currently known. This study investigated whether a productive immune response could be induced by vaccinating koalas during antibiotic treatment for Chlamydia -induced cystitis. Plasma IgG antibody levels against the C. pecorum major outer membrane protein (MOMP) dropped during antibiotic treatment in both vaccinated and unvaccinated koalas. Post-treatment, IgG levels recovered. The IgG antibodies from naturally-infected, vaccinated koalas recognised a greater proportion of the MOMP protein compared to their naturally-infected, unvaccinated counterparts. Furthermore, peripheral blood mononuclear cell gene expression revealed an up-regulation in genes related to neutrophil degranulation in vaccinated koalas during the first month post-vaccination. These findings show that vaccination of koalas while they are being treated with antibiotics for cystitis can result in the generation of a productive immune response, in the form of increased and expanded IgG production and host response through neutrophil degranulation.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3LC00113J
Abstract: Establishment of a 10 μm thick ultrathin, highly sensitive, and flexible glass cantilever integrated with a strain gauge sensor for cell stiffness measurement and real-time observation.
Publisher: SPIE
Date: 05-03-2015
DOI: 10.1117/12.2078519
Publisher: Wiley
Date: 05-12-2023
DOI: 10.1002/BIT.28288
Abstract: Biofilms are communities of bacterial cells encased in a self‐produced polymeric matrix that exhibit high tolerance toward environmental stress. Despite the plethora of research on biofilms, most P. aeruginosa biofilm models are cultured on a solid–liquid interface, and the longitudinal growth characteristics of P. aeruginosa biofilm are unclear. This study demonstrates the real‐time and noninvasive monitoring of biofilm growth using a novel dual‐chamber microfluidic device integrated with electrochemical detection capabilities to monitor pyocyanin (PYO). The growth of P. aeruginosa biofilms on the air–liquid interface (ALI) was monitored over 48 h, and its antibiotic susceptibility to 6 h exposure of 50, 400, and 1600 µg/ml of ciprofloxacin solutions was analyzed. The biofilm was treated directly on its surface and indirectly from the substratum by delivering the CIP solution to the top or bottom chamber of the microfluidic device. Results showed that P. aeruginosa biofilm developed on ALI produces PYO continuously, with the PYO production rate varying longitudinally and peak production observed between 24 and 30 h. In addition, this current study shows that the amount of PYO produced by the ALI biofilm is proportional to its viable cell numbers, which has not been previously demonstrated. Biofilm treated with ciprofloxacin solution above 400 µg/ml showed significant PYO reduction, with biofilms being killed more effectively when treatment was applied to their surfaces. The electrochemical measurement results have been verified with colony‐forming unit count results, and the strong correlation between the PYO electrical signal and the viable cell number highlights the usefulness of this approach for fast and low‐cost ALI biofilm study and antimicrobial tests.
Publisher: Wiley
Date: 21-10-2020
DOI: 10.1002/BIT.27591
Publisher: Springer Science and Business Media LLC
Date: 13-12-2013
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: 24-06-2022
DOI: 10.1038/S41378-022-00405-Y
Abstract: The electrical penetration of the cell membrane is vital for determining the cell interior via impedance cytometry. Herein, we propose a method for determining the conductivity of the cell membrane through the tilting levels of impedance pulses. When electrical penetration occurs, a high-frequency current freely passes through the cell membrane thus, the intracellular distribution can directly act on the high-frequency impedance pulses. Numerical simulation shows that an uneven intracellular component distribution can affect the tilting levels of impedance pulses, and the tilting levels start increasing when the cell membrane is electrically penetrated. Experimental evidence shows that higher detection frequencies ( MHz) lead to a wider distribution of the tilting levels of impedance pulses when measuring cell populations with four-frequency impedance cytometry. This finding allows us to determine that a detection frequency of 7 MHz is able to pass through the membrane of Euglena gracilis ( E. gracilis ) cells. Additionally, we provide a possible application of four-frequency impedance cytometry in the biomass monitoring of single E. gracilis cells. High-frequency impedance (≥7 MHz) can be applied to monitor these biomass changes, and low-frequency impedance ( MHz) can be applied to track the corresponding biovolume changes. Overall, this work demonstrates an easy determination method for the electrical penetration of the cell membrane, and the proposed platform is applicable for the multiparameter assessment of the cell state during cultivation.
Publisher: Wiley
Date: 04-10-2018
Abstract: Microalgae are an attractive feedstock organism for sustainable production of biofuels, chemicals, and biomaterials, but the ability to rationally engineer microalgae to enhance production has been limited. To enable the evolution-based selection of new hyperproducing variants of microalgae, a method is developed that combines phase-transitioning monodisperse gelatin hydrogel droplets with commercial flow cytometric instruments for high-throughput screening and selection of clonal populations of cells with desirable properties, such as high lipid productivity per time traced over multiple cell cycles. It is found that gelatin microgels enable i) the growth and metabolite (e.g., chlorophyll and lipids) production of single microalgal cells within the compartments, ii) infusion of fluorescent reporter molecules into the hydrogel matrices following a sol-gel transition, iii) selection of high-producing clonal populations of cells using flow cytometry, and iv) cell recovery under mild conditions, enabling regrowth after sorting. This user-friendly method is easily integratable into directed cellular evolution pipelines for strain improvement and can be adopted for other applications that require high-throughput processing, e.g., cellular secretion phenotypes and intercellular interactions.
Publisher: MDPI AG
Date: 15-01-2020
DOI: 10.3390/MI11010094
Abstract: Single-cell analysis is of critical importance in revealing cell-to-cell heterogeneity by characterizing in idual cells and identifying minority sub-populations of interest. Droplet-based microfluidics has been widely used in the past decade to achieve high-throughput single-cell analysis. However, to maximize the proportion of single-cell emulsification is challenging due to cell sedimentation and aggregation. The purpose of this study was to investigate the influence of single-cell encapsulation and incubation through the use of neutral buoyancy. As a proof of concept, OptiPrep™ was used to create neutrally buoyant cell suspensions of THP-1, a human monocytic leukemia cell line, for single-cell encapsulation and incubation. We found that using a neutrally buoyant suspension greatly increased the efficiency of single-cell encapsulation in microdroplets and eliminated unnecessary cell loss. Moreover, the presence of OptiPrep™ was shown to not affect cellular viability. This method significantly improved the effectiveness of single-cell study in a non-toxic environment and is expected to broadly facilitate single-cell analysis.
Publisher: Springer Science and Business Media LLC
Date: 18-01-2021
DOI: 10.1038/S41598-021-81190-Y
Abstract: Microfluidic focusing of particles (both synthetic and biological), which enables precise control over the positions of particles in a tightly focused stream, is a prerequisite step for the downstream processing, such as detection, trapping and separation. In this study, we propose a novel hydrodynamic focusing method by taking advantage of open v-shaped microstructures on a glass substrate engraved by femtosecond pulse (fs) laser. The fs laser engraved microstructures were capable of focusing polystyrene particles and live cells in rectangular microchannels at relatively low Reynolds numbers (Re). Numerical simulations were performed to explain the mechanisms of particle focusing and experiments were carried out to investigate the effects of groove depth, groove number and flow rate on the performance of the groove-embedded microchannel for particle focusing. We found out that 10-µm polystyrene particles are directed toward the channel center under the effects of the groove-induced secondary flows in low-Re flows, e.g. Re 1. Moreover, we achieved continuous focusing of live cells with different sizes ranging from 10 to 15 µm, i.e. human T-cell lymphoma Jurkat cells, rat adrenal pheochromocytoma PC12 cells and dog kidney MDCK cells. The glass grooves fabricated by fs laser are expected to be integrated with on-chip detection components, such as contact imaging and fluorescence lifetime-resolved imaging, for various biological and biomedical applications, where particle focusing at a relatively low flow rate is desirable.
Publisher: Wiley
Date: 19-12-2019
DOI: 10.1002/CYTO.A.23944
Abstract: Imaging flow cytometry is a powerful tool by virtue of its capability for high-throughput cell analysis. The advent of high-speed optical imaging methods on a microfluidic platform has significantly improved cell throughput and brought many degrees of freedom to instrumentation and applications over the last decade, but it also poses a predicament on microfluidic chips. Specifically, as the throughput increases, the flow speed also increases (currently reaching 10 m/s): consequently, the increased hydrodynamic pressure on the microfluidic chip deforms the wall of the microchannel and produces detrimental effects lead to defocused and blur image. Here, we present a comprehensive study of the effects of flow-induced microfluidic chip wall deformation on imaging flow cytometry. We fabricated three types of microfluidic chips with the same geometry and different degrees of stiffness made of polydimethylsiloxane (PDMS) and glass to investigate material influence on image quality. First, we found the maximum deformation of a PDMS microchannel was >60 μm at a pressure of 0.6 MPa, while no appreciable deformation was identified in a glass microchannel at the same pressure. Second, we found the deviation of lag time that indicating velocity difference of migrating microbeads due to the deformation of the microchannel was 29.3 ms in a PDMS microchannel and 14.9 ms in a glass microchannel. Third, the glass microchannel focused cells into a slightly narrower stream in the X-Y plane and a significantly narrower stream in the Z-axis direction (focusing percentages were increased 30%, 32%, and 5.7% in the glass channel at flow velocities of 0.5, 1.5, and 3 m/s, respectively), and the glass microchannel showed stabler equilibrium positions of focused cells regardless of flow velocity. Finally, we achieved the world's fastest imaging flow cytometry by combining a glass microfluidic device with an optofluidic time-stretch microscopy imaging technique at a flow velocity of 25 m/s. © 2019 International Society for Advancement of Cytometry.
Publisher: MDPI AG
Date: 12-10-2022
DOI: 10.3390/S22207743
Abstract: Impedance cytometry is wildly used in single-cell detection, and its sensitivity is essential for determining the status of single cells. In this work, we focus on the effect of electrode gap on detection sensitivity. Through comparing the electrode span of 1 µm and 5 µm, our work shows that narrowing the electrode span could greatly improve detection sensitivity. The mechanism underlying the sensitivity improvement was analyzed via numerical simulation. The small electrode gap (1 µm) allows the electric field to concentrate near the detection area, resulting in a high sensitivity for tiny particles. This finding is also verified with the mixture suspension of 1 µm and 3 µm polystyrene beads. As a result, the electrodes with 1 µm gap can detect more 1 µm beads in the suspension than electrodes with 5 µm gap. Additionally, for single yeast cells analysis, it is found that impedance cytometry with 1 µm electrodes gap can easily distinguish budding yeast cells, which cannot be realized by the impedance cytometry with 5 µm electrodes gap. All experimental results support that narrowing the electrode gap is necessary for tiny particle detection, which is an important step in the development of submicron and nanoscale impedance cytometry.
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.CELL.2018.08.028
Abstract: A fundamental challenge of biology is to understand the vast heterogeneity of cells, particularly how cellular composition, structure, and morphology are linked to cellular physiology. Unfortunately, conventional technologies are limited in uncovering these relations. We present a machine-intelligence technology based on a radically different architecture that realizes real-time image-based intelligent cell sorting at an unprecedented rate. This technology, which we refer to as intelligent image-activated cell sorting, integrates high-throughput cell microscopy, focusing, and sorting on a hybrid software-hardware data-management infrastructure, enabling real-time automated operation for data acquisition, data processing, decision-making, and actuation. We use it to demonstrate real-time sorting of microalgal and blood cells based on intracellular protein localization and cell-cell interaction from large heterogeneous populations for studying photosynthesis and atherothrombosis, respectively. The technology is highly versatile and expected to enable machine-based scientific discovery in biological, pharmaceutical, and medical sciences.
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: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9LC00785G
Abstract: This work comprehensively reviews the fundamentals and applications of different types of microfluidic techniques for the focusing of sub-micrometer particles.
Publisher: Springer Science and Business Media LLC
Date: 28-05-2022
DOI: 10.1186/S12951-022-01471-0
Abstract: Liquid metal (LM) can be integrated into microfluidic channel, bringing new functionalities of microfluidics and opening a new window for soft microfluidic electronics, due to the superior advantages of the conductivity and deformability of LMs. However, patterning the LMs into microfluidic channels requires either selective surface wetting or complex fabrication process. In this work, we develop a method to pattern the LMs onto the soft elastomer via soft lithographic process for fabrication of soft microfluidic sensors without the surface modification, bulky facilities, and complicated processes. The combination of the interfacial hydrogen bond and surface tension enables the LM patterns transfer to the soft elastomer. The transferred LM patterns with an ellipse-like cross-section further improve the stability under the mechanical deformation. Three proof-of-concept experiments were conducted to demonstrate the utilization of this method for development of thermochromic sensors, self-powered capacity sensors and flexible biosensor for glucose detection. In summary, the proposed method offers a new patterning method to obtain soft microfluidic sensors and brings new possibilities for microfluidics-related wearable devices.
Publisher: American Chemical Society (ACS)
Date: 07-10-2022
DOI: 10.1021/ACSSENSORS.2C01351
Abstract: The benefits of impedance cytometry include high-throughput and label-free detection, while long-term calibration is required to remove the effects of the detection circuits. This study presents a novel impedance cytometry system, called parallel impedance cytometry, to simplify the calibration and analysis of the impedance signals. Furthermore, target objects can be detected even when benchmarked against similar objects. Parallel dual microchannels allow the simultaneous detection of reference and target particles in two separate microchannels, without the premixing of reference and target suspensions. The impedance pulses of both can appear separately on the opposite sides of the same time series, which have been verified via simulation and experimental results. Raw impedance signals can easily distinguish target particles from reference ones. Polystyrene beads with different sizes ranging from nano- to microscale (e.g., 500, 750 nm, 1, 2, 3, and 4.5 μm) confirm the nanosensitivity of the system. In addition, the detection of antibiotic-treated
Publisher: American Chemical Society (ACS)
Date: 29-07-2021
Location: United States of America
Start Date: 2023
End Date: 12-2023
Amount: $682,792.00
Funder: Australian Research Council
View Funded ActivityStart Date: 08-2020
End Date: 08-2024
Amount: $420,000.00
Funder: Australian Research Council
View Funded Activity