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George A, Akbaridoust F, Zainal Abidin NA, Nesbitt WS, Marusic I. Characterisation of hydrodynamic trapping in microfluidic cross-slot devices for high strain rate applications. LAB ON A CHIP 2023. [PMID: 37305977 DOI: 10.1039/d3lc00256j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Hydrodynamic trapping of a particle or cluster of particles based on contact and non-contact approaches has brought prominent insights to micro-nano scale applications. Of the non-contact methods, image-based real-time control in cross-slot microfluidic devices is one of the most promising potential platform for single cellular assays. Here, we report results from experiments conducted in two cross-slot microfluidic channels of different widths, with varying real-time delay of the control algorithm and different magnification. Sustained trapping of 5 μm diameter particles was achieved with high strain rates, of order 102 s-1, higher than in any previous studies. Our experiments show that the maximum attainable strain rate is a function of the real-time delay of the control algorithm and the particle resolution (pixel/μm). Therefore, we anticipate that with further reduced time delays and enhanced particle resolution, considerably higher strain rates can be attained, opening the platform to single cellular assay studies where very high strain rates are required.
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Affiliation(s)
- Aravind George
- Department of Mechanical Engineering, University of Melbourne, VIC 3010, Australia.
| | - Farzan Akbaridoust
- Department of Mechanical Engineering, University of Melbourne, VIC 3010, Australia.
| | - Nurul A Zainal Abidin
- The Australian Centre for Blood Diseases, Monash University, 99 Commercial Road, Melbourne, VIC 3004, Australia
| | - Warwick S Nesbitt
- The Australian Centre for Blood Diseases, Monash University, 99 Commercial Road, Melbourne, VIC 3004, Australia
| | - Ivan Marusic
- Department of Mechanical Engineering, University of Melbourne, VIC 3010, Australia.
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2
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Abstract
Actin cytoskeleton force generation, sensing, and adaptation are dictated by the bending and twisting mechanics of filaments. Here, we use magnetic tweezers and microfluidics to twist and pull individual actin filaments and evaluate their response to applied loads. Twisted filaments bend and dissipate torsional strain by adopting a supercoiled plectoneme. Pulling prevents plectoneme formation, which causes twisted filaments to sever. Analysis over a range of twisting and pulling forces and direct visualization of filament and single subunit twisting fluctuations yield an actin filament torsional persistence length of ~10 µm, similar to the bending persistence length. Filament severing by cofilin is driven by local twist strain at boundaries between bare and decorated segments and is accelerated by low pN pulling forces. This work explains how contractile forces generated by myosin motors accelerate filament severing by cofilin and establishes a role for filament twisting in the regulation of actin filament stability and assembly dynamics.
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3
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Verburg T, Schaap A, Zhang S, den Toonder J, Wang Y. Enhancement of microalgae growth using magnetic artificial cilia. Biotechnol Bioeng 2021; 118:2472-2481. [PMID: 33738795 PMCID: PMC8251745 DOI: 10.1002/bit.27756] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/10/2021] [Accepted: 03/16/2021] [Indexed: 12/18/2022]
Abstract
Microalgae have shown great potential as a source of biofuels, food, and other bioproducts. More recently, microfluidic devices have been employed in microalgae-related studies. However, at small fluid volumes, the options for controlling flow conditions are more limited and mixing becomes largely reliant on diffusion. In this study, we fabricated magnetic artificial cilia (MAC) and implemented them in millimeter scale culture wells and conducted growth experiments with Scenedesmus subspicatus while actuating the MAC in a rotating magnetic field to create flow and mixing. In addition, surface of MAC was made hydrophilic using plasma treatment and its effect on growth was compared with untreated, hydrophobic MAC. The experiments showed that the growth was enhanced by ten and two times with hydrophobic and hydrophilic MAC, respectively, compared with control groups which contain no MAC. This technique can be used to investigate mixing and flow in small sample volumes, and the enhancement in growth can be beneficial for the throughput of screening studies. Moreover, the methods used for creating and controlling MAC can be easily adopted in labs without microfabrication infrastructures, and they can be mastered by people with little prior experience in microfluidics.
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Affiliation(s)
- Thijn Verburg
- Eindhoven University of Technology, Eindhoven, The Netherlands
| | | | - Shuaizhong Zhang
- Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute of Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Jaap den Toonder
- Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute of Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Ye Wang
- Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute of Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
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4
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Bibeau JP, Gray S, De La Cruz EM. Clusters of a Few Bound Cofilins Sever Actin Filaments. J Mol Biol 2021; 433:166833. [PMID: 33524412 DOI: 10.1016/j.jmb.2021.166833] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 02/06/2023]
Abstract
Cofilin is an essential actin filament severing protein that accelerates the assembly dynamics and turnover of actin networks by increasing the number of filament ends where subunits add and dissociate. It binds filament subunits stoichiometrically and cooperatively, forming clusters of contiguously-bound cofilin at sub-saturating occupancies. Filaments partially occupied with cofilin sever at boundaries between bare and cofilin-decorated segments. Imaging studies concluded that bound clusters must reach a critical size (Cc) of 13-100 cofilins to sever filaments. In contrast, structural and modeling studies suggest that a few or even a single cofilin can sever filaments, possibly with different severing rate constants. How clusters grow through the cooperative incorporation of additional cofilin molecules, specifically if they elongate asymmetrically or uniformly from both ends and if they are modulated by filament shape and external force, also lacks consensus. Here, using hydrodynamic flow to visualize individual actin filaments with TIRF microscopy, we found that neither flow-induced filament bending, tension, nor surface attachment conditions substantially affected the kinetics of cofilin binding to actin filaments. Clusters of bound cofilin preferentially extended toward filament pointed ends and displayed severing competency at small sizes (Cc < 3), with no detectable severing dependence on cluster size. These data support models in which small clusters of cofilin introduce local, but asymmetric, structural changes in actin filaments that promote filament severing with a rate constant that depends weakly on the size of the cluster.
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Affiliation(s)
- Jeffrey P Bibeau
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, United States
| | - Shawn Gray
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, United States
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, United States.
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5
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Kimkes TEP, Heinemann M. How bacteria recognise and respond to surface contact. FEMS Microbiol Rev 2020; 44:106-122. [PMID: 31769807 PMCID: PMC7053574 DOI: 10.1093/femsre/fuz029] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 11/23/2019] [Indexed: 12/27/2022] Open
Abstract
Bacterial biofilms can cause medical problems and issues in technical systems. While a large body of knowledge exists on the phenotypes of planktonic and of sessile cells in mature biofilms, our understanding of what happens when bacteria change from the planktonic to the sessile state is still very incomplete. Fundamental questions are unanswered: for instance, how do bacteria sense that they are in contact with a surface, and what are the very initial cellular responses to surface contact. Here, we review the current knowledge on the signals that bacteria could perceive once they attach to a surface, the signal transduction systems that could be involved in sensing the surface contact and the cellular responses that are triggered as a consequence to surface contact ultimately leading to biofilm formation. Finally, as the main obstacle in investigating the initial responses to surface contact has been the difficulty to experimentally study the dynamic response of single cells upon surface attachment, we also review recent experimental approaches that could be employed to study bacterial surface sensing, which ultimately could lead to an improved understanding of how biofilm formation could be prevented.
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Affiliation(s)
- Tom E P Kimkes
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Matthias Heinemann
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
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6
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Akbaridoust F, de Silva CM, Szydzik C, Mitchell A, Marusic I, Nesbitt WS. Experimental fluid dynamics characterization of a novel micropump-mixer. BIOMICROFLUIDICS 2020; 14:044116. [PMID: 32849975 PMCID: PMC7442494 DOI: 10.1063/5.0012240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/11/2020] [Indexed: 06/11/2023]
Abstract
The application of lab-on-a-chip systems to biomedical engineering and medical biology is rapidly growing. Reciprocating micropumps show significant promise as automated bio-fluid handling systems and as active reagent-to-sample mixers. Here, we describe a thorough fluid dynamic analysis of an active micro-pump-mixer designed for applications of preclinical blood analysis and clinical diagnostics in hematology. Using high-speed flow visualization and micro-particle image velocimetry measurements, a parametric study is performed to investigate the fluid dynamics of six discrete modes of micropump operation. With this approach, we identify an actuation regime that results in optimal sample flow rates while concomitantly maximizing reagent-to-sample mixing.
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Affiliation(s)
| | - C. M. de Silva
- School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - C. Szydzik
- The Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria 3004, Australia
| | - A. Mitchell
- School of Engineering, RMIT University, Melbourne, Victoria 3000, Australia
| | - I. Marusic
- Department of Mechanical Engineering, University of Melbourne, Parkville, Victoria 3010, Australia
| | - W. S. Nesbitt
- The Australian Centre for Blood Diseases, Monash University, Melbourne, Victoria 3004, Australia
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7
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Force and phosphate release from Arp2/3 complex promote dissociation of actin filament branches. Proc Natl Acad Sci U S A 2020; 117:13519-13528. [PMID: 32461373 DOI: 10.1073/pnas.1911183117] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Networks of branched actin filaments formed by Arp2/3 complex generate and experience mechanical forces during essential cellular functions, including cell motility and endocytosis. External forces regulate the assembly and architecture of branched actin networks both in vitro and in cells. Considerably less is known about how mechanical forces influence the disassembly of actin filament networks, specifically, the dissociation of branches. We used microfluidics to apply force to branches formed from purified muscle actin and fission yeast Arp2/3 complex and observed debranching events in real time with total internal reflection fluorescence microscopy. Low forces in the range of 0 pN to 2 pN on branches accelerated their dissociation from mother filaments more than two orders of magnitude, from hours to <1 min. Neither force on the mother filament nor thermal fluctuations in mother filament shape influenced debranching. Arp2/3 complex at branch junctions adopts two distinct mechanical states with different sensitivities to force, which we name "young/strong" and "old/weak." The "young/strong" state 1 has adenosine 5'-diphosphate (ADP)-P i bound to Arp2/3 complex. Phosphate release converts Arp2/3 complex into the "old/weak" state 2 with bound ADP, which is 20 times more sensitive to force than state 1. Branches with ADP-Arp2/3 complex are more sensitive to debranching by fission yeast GMF (glia maturation factor) than branches with ADP-P i -Arp2/3 complex. These findings suggest that aging of branch junctions by phosphate release from Arp2/3 complex and mechanical forces contribute to disassembling "old" actin filament branches in cells.
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8
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Zhang P, Wang G, Zhang X, Li YQ. Single-Acquisition 2-D Multifocal Raman Spectroscopy Using Compressive Sensing. Anal Chem 2020; 92:1326-1332. [PMID: 31793766 DOI: 10.1021/acs.analchem.9b04495] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Confocal Raman microscopy is a powerful method for nondestructive and noninvasive detection of chemicals with high spatial resolution, but its long acquisition time hinders its applications in large-scale monitoring of fast dynamics. Here, we report the development of a compressive sensing technique for single-acquisition multifocal Raman spectroscopy, which is capable of improving the speed of conventional confocal Raman spectroscopy by 2-3 orders of magnitude. A sample is excited with a 2-D multifocus pattern, and the Raman scatterings from the multiple foci were projected onto the spectrometer's entrance in a 2-D array. The superimposed spectra within each row of the array were processed with an algorithm such that the spectra from the individual foci were retrieved in a single acquisition and with reduced noise. The performances of the developed technique were demonstrated by parallel Raman spectroscopy of multiple individual particles as well as by single-acquisition confocal Raman imaging of a large scale with high spatial resolution when combined with spatially sparse sampling. The technique is expected to find wide applications in investigating fast dynamics in large-scale biological systems.
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Affiliation(s)
- Pengfei Zhang
- School of Precision Instruments and Optoelectronics Engineering , Tianjin University , Tianjin 300072 , P. R. China
| | - Guiwen Wang
- Guangxi Academy of Sciences , 98 Daling Road , Nanning , Guangxi 530007 , P. R. China
| | - Xiujuan Zhang
- Guangxi Academy of Sciences , 98 Daling Road , Nanning , Guangxi 530007 , P. R. China
| | - Yong-Qing Li
- The Laboratory of Biomedical Photonics & Engineering , Guangxi Medical University , Nanning , Guangxi 530021 , P. R. China.,Department of Physics , East Carolina University , Greenville , North Carolina 27858-4353 , United States
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9
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Guerrini L, Alvarez-Puebla RA. Surface-Enhanced Raman Spectroscopy in Cancer Diagnosis, Prognosis and Monitoring. Cancers (Basel) 2019; 11:E748. [PMID: 31146464 PMCID: PMC6627759 DOI: 10.3390/cancers11060748] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 05/23/2019] [Accepted: 05/27/2019] [Indexed: 12/28/2022] Open
Abstract
As medicine continues to advance our understanding of and knowledge about the complex and multifactorial nature of cancer, new major technological challenges have emerged in the design of analytical methods capable of characterizing and assessing the dynamic heterogeneity of cancer for diagnosis, prognosis and monitoring, as required by precision medicine. With this aim, novel nanotechnological approaches have been pursued and developed for overcoming intrinsic and current limitations of conventional methods in terms of rapidity, sensitivity, multiplicity, non-invasive procedures and cost. Eminently, a special focus has been put on their implementation in liquid biopsy analysis. Among optical nanosensors, those based on surface-enhanced Raman scattering (SERS) have been attracting tremendous attention due to the combination of the intrinsic prerogatives of the technique (e.g., sensitivity and structural specificity) and the high degree of refinement in nano-manufacturing, which translate into reliable and robust real-life applications. In this review, we categorize the diverse strategic approaches of SERS biosensors for targeting different classes of tumor biomarkers (cells, nucleic acids and proteins) by illustrating key recent research works. We will also discuss the current limitations and future research challenges to be addressed to improve the competitiveness of SERS over other methodologies in cancer medicine.
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Affiliation(s)
- Luca Guerrini
- Department of Physical and Inorganic Chemistry and EMaS, Universitat Rovira I Virgili, Carrer de Marcel.lí Domingo s/n, 43007 Tarragona, Spain.
| | - Ramon A Alvarez-Puebla
- Department of Physical and Inorganic Chemistry and EMaS, Universitat Rovira I Virgili, Carrer de Marcel.lí Domingo s/n, 43007 Tarragona, Spain.
- ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain.
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10
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Prado RC, Borges ER. MICROBIOREACTORS AS ENGINEERING TOOLS FOR BIOPROCESS DEVELOPMENT. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2018. [DOI: 10.1590/0104-6632.20180354s20170433] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- R. C. Prado
- Federal University of Rio de Janeiro, Brazil
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11
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Armbrecht L, Gabernet G, Kurth F, Hiss JA, Schneider G, Dittrich PS. Characterisation of anticancer peptides at the single-cell level. LAB ON A CHIP 2017; 17:2933-2940. [PMID: 28736788 PMCID: PMC6440648 DOI: 10.1039/c7lc00505a] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The development of efficacious anticancer therapeutics is difficult due to the heterogeneity of the cellular response to chemotherapy. Anticancer peptides (ACPs) are promising drug candidates that have been shown to be active against a range of cancer cells. However, few ACP studies focus on tumour single-cell heterogeneities. In order to address this need, we developed a microfluidic device and an imaging procedure that enable the capture, monitoring, and analysis of several hundred single cells for the study of drug response. MCF-7 human breast adenocarcinoma cells were captured in hydrodynamic traps and isolated in individual microchambers of less than 100 pL volume. With pneumatic valves, different sets of microchambers were actuated to expose the cells to various drugs. Here, the effect of three membranolytic ACPs - melittin, aurein 1.2 and aurein 2.2 - was investigated by monitoring the efflux of calcein from single MCF-7 cells. The loss of membrane integrity was observed with two different strategies that allow either focusing on one cell for mechanistic studies or parallel analysis of hundreds of individual cells. In general, the device is applicable to the analysis of the effect of various drugs on a large number of different cell types. The platform will enable us in the future to determine the origin of heterogeneous responses on pharmacological substances like ACPs within cell populations by combining it with other on-chip analytical methods.
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Affiliation(s)
- L Armbrecht
- Department of Biosystems Science and Engineering, ETH Zurich, Switzerland.
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12
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Sheats J, Sclavi B, Cosentino Lagomarsino M, Cicuta P, Dorfman KD. Role of growth rate on the orientational alignment of Escherichia coli in a slit. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170463. [PMID: 28680690 PMCID: PMC5493932 DOI: 10.1098/rsos.170463] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 05/19/2017] [Indexed: 05/08/2023]
Abstract
We present experimental data on the nematic alignment of Escherichia coli bacteria confined in a slit, with an emphasis on the effect of growth rate and corresponding changes in cell aspect ratio. Global alignment with the channel walls arises from the combination of local nematic ordering of nearby cells, induced by cell division and the elongated shape of the cells, and the preferential orientation of cells proximate to the side walls of the slit. Decreasing the growth rate leads to a decrease in alignment with the walls, which is attributed primarily to effects of changing cell aspect ratio rather than changes in the variance in cell area. Decreasing confinement also reduces the degree of alignment by a similar amount as a decrease in the growth rate, but the distribution of the degree of alignment differs. The onset of alignment with the channel walls is coincident with the slits reaching their steady-state occupancy and connected to the re-orientation of locally aligned regions with respect to the walls during density fluctuations.
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Affiliation(s)
- Julian Sheats
- Department of Chemical Engineering and Materials Science, University of Minnesota—Twin Cities, 421 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Bianca Sclavi
- LBPA, UMR 8113 du CNRS, École Normale Supérieure de Cachan, Cachan, France
| | - Marco Cosentino Lagomarsino
- Sorbonne Universités, Université Pierre et Marie Curie, 4 Place Jussieu, Paris, France
- CNRS, UMR7238 Computational and Quantitative Biology, Paris, France
- IFOM Institute for Molecular Oncology, Milan, Italy
| | - Pietro Cicuta
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Kevin D. Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota—Twin Cities, 421 Washington Avenue SE, Minneapolis, MN 55455, USA
- Author for correspondence: Kevin D. Dorfman e-mail:
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13
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Affiliation(s)
- Judit Randek
- Division of Biotechnology, IFM, Linköping University, Linköping, Sweden
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14
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Brimmo AT, Qasaimeh MA. Microfluidic Probes and Quadrupoles: A new era of open microfluidics. IEEE NANOTECHNOLOGY MAGAZINE 2017. [DOI: 10.1109/mnano.2016.2633678] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Fang C, Ji F, Shu Z, Gao D. Determination of the temperature-dependent cell membrane permeabilities using microfluidics with integrated flow and temperature control. LAB ON A CHIP 2017; 17:951-960. [PMID: 28197586 DOI: 10.1039/c6lc01523a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We developed an integrated microfluidic platform for instantaneous flow and localized temperature control. The platform consisted of a flow-focusing region for sample delivery and a cross-junction region embedded with a microheater for cell trapping and localized temperature control by using an active feedback control system. We further used it to measure the membrane transport properties of Jurkat cells, including the osmotically inactive cell volume (Vb) and cell membrane permeabilities to water (Lp) and to cryoprotective agent (CPA) solutions (dimethyl sulfoxide (DMSO) in this study) (PS) at various temperatures (room temperature, 30 °C, and 37 °C). Such characteristics of cells are of great importance in many applications, especially in optimal cryopreservation. With the results, the corresponding activation energy for water and CPA transport was calculated. The comparison of the results from the current study with reference data indicates that the developed platform is a reliable tool for temperature-dependent cell behavior study, which provides valuable tools for general cell manipulation applications with precise temperature control.
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Affiliation(s)
- Cifeng Fang
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA.
| | - Fujun Ji
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA. and School of Information, Capital University of Economics and Business, Beijing 100070, China
| | - Zhiquan Shu
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA. and School of Mechanical and Materials Engineering, Washington State University, Everett, WA 98201, USA.
| | - Dayong Gao
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA.
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16
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Kelley SO. New Technologies for Rapid Bacterial Identification and Antibiotic Resistance Profiling. SLAS Technol 2016; 22:113-121. [PMID: 27879409 DOI: 10.1177/2211068216680207] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Conventional approaches to bacterial identification and drug susceptibility testing typically rely on culture-based approaches that take 2 to 7 days to return results. The long turnaround times contribute to the spread of infectious disease, negative patient outcomes, and the misuse of antibiotics that can contribute to antibiotic resistance. To provide new solutions enabling faster bacterial analysis, a variety of approaches are under development that leverage single-cell analysis, microfluidic concentration and detection strategies, and ultrasensitive readout mechanisms. This review discusses recent advances in this area and the potential of new technologies to enable more effective management of infectious disease.
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Affiliation(s)
- Shana O Kelley
- 1 Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada.,2 Department of Chemistry, Faculty of Arts and Science, University of Toronto, Toronto, ON, Canada.,3 Institute for Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,4 Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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17
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Haward SJ. Microfluidic extensional rheometry using stagnation point flow. BIOMICROFLUIDICS 2016; 10:043401. [PMID: 27099647 PMCID: PMC4826384 DOI: 10.1063/1.4945604] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/01/2016] [Indexed: 05/07/2023]
Abstract
Characterization of the extensional rheometry of fluids with complex microstructures is of great relevance to the optimization of a wide range of industrial applications and for understanding various natural processes, biological functions, and diseases. However, quantitative measurement of the extensional properties of complex fluids has proven elusive to researchers, particularly in the case of low viscosity, weakly elastic fluids. For some time, microfluidic platforms have been recognized as having the potential to fill this gap and various approaches have been proposed. This review begins with a general discussion of extensional viscosity and the requirements of an extensional rheometer, before various types of extensional rheometers (particularly those of microfluidic design) are critically discussed. A specific focus is placed on microfluidic stagnation point extensional flows generated by cross-slot type devices, for which some important developments have been reported during the last 10 years. Additional emphasis is placed on measurements made on relevant biological fluids. Finally, the operating limits of the cross-slot extensional rheometer (chiefly imposed by the onset of elastic and inertial flow instabilities) are discussed.
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Affiliation(s)
- S J Haward
- Okinawa Institute of Science and Technology Graduate University , Onna, Okinawa 904-0495, Japan
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18
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Stokes trap for multiplexed particle manipulation and assembly using fluidics. Proc Natl Acad Sci U S A 2016; 113:3976-81. [PMID: 27035979 DOI: 10.1073/pnas.1525162113] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ability to confine and manipulate single particles and molecules has revolutionized several fields of science. Hydrodynamic trapping offers an attractive method for particle manipulation in free solution without the need for optical, electric, acoustic, or magnetic fields. Here, we develop and demonstrate the Stokes trap, which is a new method for trapping multiple particles using only fluid flow. We demonstrate simultaneous manipulation of two particles in a simple microfluidic device using model predictive control. We further show that this approach can be used for fluidic-directed assembly of multiple particles in solution. Overall, this technique opens new vistas for fundamental studies of particle-particle interactions and provides a new method for the directed assembly of colloidal particles.
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19
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Alicia TGG, Yang C, Wang Z, Nguyen NT. Combinational concentration gradient confinement through stagnation flow. LAB ON A CHIP 2016; 16:368-76. [PMID: 26671507 DOI: 10.1039/c5lc01137j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Concentration gradient generation in microfluidics is typically constrained by two conflicting mass transport requirements: short characteristic times (τ) for precise temporal control of concentration gradients but at the expense of high flow rates and hence, high flow shear stresses (σ). To decouple the limitations from these parameters, here we propose the use of stagnation flows to confine concentration gradients within large velocity gradients that surround the stagnation point. We developed a modified cross-slot (MCS) device capable of feeding binary and combinational concentration sources in stagnation flows. We show that across the velocity well, source-sink pairs can form permanent concentration gradients. As source-sink concentration pairs are continuously supplied to the MCS, a permanently stable concentration gradient can be generated. Tuning the flow rates directly controls the velocity gradients, and hence the stagnation point location, allowing the confined concentration gradient to be focused. In addition, the flow rate ratio within the MCS rapidly controls (τ ∼ 50 ms) the location of the stagnation point and the confined combinational concentration gradients at low flow shear (0.2 Pa < σ < 2.9 Pa). The MCS device described in this study establishes the method for using stagnation flows to rapidly generate and position low shear combinational concentration gradients for shear sensitive biological assays.
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Affiliation(s)
- Toh G G Alicia
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore. and Microfluidics Manufacturing Programme, Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 63807 Singapore
| | - Chun Yang
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore.
| | - Zhiping Wang
- Microfluidics Manufacturing Programme, Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 63807 Singapore
| | - Nam-Trung Nguyen
- QLD Micro- and Nanotechnology Centre, Nathan campus, Griffith University, 170 Kessels Road QLD 4111, Australia.
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Fang C, Lee D, Stober B, Fuller GG, Shen AQ. Integrated microfluidic platform for instantaneous flow and localized temperature control. RSC Adv 2015. [DOI: 10.1039/c5ra19944a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We developed an integrated microfluidic platform for instantaneous flow and localized temperature control.
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Affiliation(s)
- Cifeng Fang
- Department of Mechanical Engineering
- University of Washington
- Seattle
- USA
| | - Doojin Lee
- Micro/Bio/Nanofluidics Unit
- Okinawa Institute of Science and Technology Graduate University
- Okinawa
- Japan
| | - Boris Stober
- Department of Mechanical Engineering
- The University of British Columbia
- Vancouver
- Canada
| | | | - Amy Q. Shen
- Department of Mechanical Engineering
- University of Washington
- Seattle
- USA
- Micro/Bio/Nanofluidics Unit
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