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Tang Q, Zhou S, Huang L, Chen Z. Diversity of 2D Acoustofluidic Fields in an Ultrasonic Cavity Generated by Multiple Vibration Sources. MICROMACHINES 2019; 10:E803. [PMID: 31766721 PMCID: PMC6952793 DOI: 10.3390/mi10120803] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 12/03/2022]
Abstract
Two-dimensional acoustofluidic fields in an ultrasonic chamber actuated by segmented ring-shaped vibration sources with different excitation phases are simulated by COMSOL Multiphysics. Diverse acoustic streaming patterns, including aggregation and rotational modes, can be feasibly generated by the excitation of several sessile ultrasonic sources which only vibrate along radial direction. Numerical simulation of particle trajectory driven by acoustic radiation force and streaming-induced drag force also demonstrates that micro-scale particles suspended in the acoustofluidic chamber can be trapped in the velocity potential well of fluid flow or can rotate around the cavity center with the circumferential acoustic streaming field. Preliminary investigation of simple Russian doll- or Matryoshka-type configurations (double-layer vibration sources) provide a novel method of multifarious structure design in future researches on the combination of phononic crystals and acoustic streaming fields. The implementation of multiple segmented ring-shaped vibration sources offers flexibility for the control of acoustic streaming fields in microfluidic devices for various applications. We believe that this kind of acoustofluidic design is expected to be a promising tool for the investigation of rapid microfluidic mixing on a chip and contactless rotational manipulation of biosamples, such as cells or nematodes.
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Affiliation(s)
- Qiang Tang
- Faculty of Mechanical and Material Engineering, Huaiyin Institute of Technology, Huaian 223001, China; (S.Z.); (Z.C.)
| | - Song Zhou
- Faculty of Mechanical and Material Engineering, Huaiyin Institute of Technology, Huaian 223001, China; (S.Z.); (Z.C.)
| | - Liang Huang
- School of Instrument Science and Opto-Electronics Engineering, Hefei University of Technology, Hefei 230009, China;
| | - Zhong Chen
- Faculty of Mechanical and Material Engineering, Huaiyin Institute of Technology, Huaian 223001, China; (S.Z.); (Z.C.)
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DEP-on-a-Chip: Dielectrophoresis Applied to Microfluidic Platforms. MICROMACHINES 2019; 10:mi10060423. [PMID: 31238556 PMCID: PMC6630590 DOI: 10.3390/mi10060423] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/15/2019] [Accepted: 06/19/2019] [Indexed: 01/09/2023]
Abstract
Dielectric particles in a non-uniform electric field are subject to a force caused by a phenomenon called dielectrophoresis (DEP). DEP is a commonly used technique in microfluidics for particle or cell separation. In comparison with other separation methods, DEP has the unique advantage of being label-free, fast, and accurate. It has been widely applied in microfluidics for bio-molecular diagnostics and medical and polymer research. This review introduces the basic theory of DEP, its advantages compared with other separation methods, and its applications in recent years, in particular, focusing on the different electrode types integrated into microfluidic chips, fabrication techniques, and operation principles.
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Lewpiriyawong N, Xu G, Yang C. Enhanced cell trapping throughput using DC-biased AC electric field in a dielectrophoresis-based fluidic device with densely packed silica beads. Electrophoresis 2018; 39:878-886. [DOI: 10.1002/elps.201700395] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 12/13/2017] [Accepted: 12/13/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Nuttawut Lewpiriyawong
- School of Mechanical and Aerospace Engineering; Nanyang Technological University; Singapore
| | - Guolin Xu
- Institute of Bioengineering and Nanotechnology; Singapore
| | - Chun Yang
- School of Mechanical and Aerospace Engineering; Nanyang Technological University; Singapore
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4
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Lee F, Iliescu C, Yu F, Yu H. Constrained spheroids/organoids in perfusion culture. Methods Cell Biol 2018; 146:43-65. [DOI: 10.1016/bs.mcb.2018.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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5
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Liu F, Jiang L, Tan HM, Yadav A, Biswas P, van der Maarel JRC, Nijhuis CA, van Kan JA. Separation of superparamagnetic particles through ratcheted Brownian motion and periodically switching magnetic fields. BIOMICROFLUIDICS 2016; 10:064105. [PMID: 27917252 PMCID: PMC5116023 DOI: 10.1063/1.4967965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 11/04/2016] [Indexed: 06/06/2023]
Abstract
Brownian ratchet based particle separation systems for application in lab on chip devices have drawn interest and are subject to ongoing theoretical and experimental investigations. We demonstrate a compact microfluidic particle separation chip, which implements an extended on-off Brownian ratchet scheme that actively separates and sorts particles using periodically switching magnetic fields, asymmetric sawtooth channel sidewalls, and Brownian motion. The microfluidic chip was made with Polydimethylsiloxane (PDMS) soft lithography of SU-8 molds, which in turn was fabricated using Proton Beam Writing. After bonding of the PDMS chip to a glass substrate through surface activation by oxygen plasma treatment, embedded electromagnets were cofabricated by the injection of InSn metal into electrode channels. This fabrication process enables rapid production of high resolution and high aspect ratio features, which results in parallel electrodes accurately aligned with respect to the separation channel. The PDMS devices were tested with mixtures of 1.51 μm, 2.47 μm, and 2.60 μm superparamagnetic particles suspended in water. Experimental results show that the current device design has potential for separating particles with a size difference around 130 nm. Based on the promising results, we will be working towards extending this design for the separation of cells or biomolecules.
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Affiliation(s)
- Fan Liu
- Department of Physics, National University of Singapore , Singapore 117542
| | - Li Jiang
- Department of Chemistry, National University of Singapore , Singapore 117543
| | - Huei Ming Tan
- Engineering Science Programme, National University of Singapore , Singapore 117576
| | - Ashutosh Yadav
- Department of Physics, National University of Singapore , Singapore 117542
| | - Preetika Biswas
- Department of Physics, National University of Singapore , Singapore 117542
| | | | - Christian A Nijhuis
- Department of Chemistry, National University of Singapore , Singapore 117543
| | - Jeroen A van Kan
- Department of Physics, National University of Singapore , Singapore 117542
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Fernandez RE, Koklu A, Mansoorifar A, Beskok A. Platinum black electrodeposited thread based electrodes for dielectrophoretic assembly of microparticles. BIOMICROFLUIDICS 2016; 10:033101. [PMID: 27158295 PMCID: PMC4833733 DOI: 10.1063/1.4946015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/13/2016] [Indexed: 05/12/2023]
Abstract
We report dielectrophoretic (DEP) assembly of biological cells and microparticles using platinum-black electrodeposited conductive textile fiber. The three-dimensional conductive structures with high aspect ratios were found to facilitate high electric field regions, as revealed by scanning electron microscope characterization. The effective conducting area (Aeff) and its stability of thread electrodes were estimated using electrochemical methods. Potential of platinum black electrodeposited thread as 3-D electrodes for creating high gradient electrical field for dielectrophoretic assembly of microspheres and Saccharomyces cerevisiae (yeast cells) into 1D and two-dimensional structures over long ranges under the application of low voltages (4-10 Vpp) has been demonstrated. The formation of highly ordered pearl chains of microparticles using thread electrodes when subjected to dielectrophoresis (DEP) has been discussed in detail.
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Affiliation(s)
- Renny Edwin Fernandez
- Department of Mechanical Engineering, Southern Methodist University , Dallas, Texas 75205, USA
| | - Anil Koklu
- Department of Mechanical Engineering, Southern Methodist University , Dallas, Texas 75205, USA
| | - Amin Mansoorifar
- Department of Mechanical Engineering, Southern Methodist University , Dallas, Texas 75205, USA
| | - Ali Beskok
- Department of Mechanical Engineering, Southern Methodist University , Dallas, Texas 75205, USA
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Marchalot J, Chateaux JF, Faivre M, Mertani HC, Ferrigno R, Deman AL. Dielectrophoretic capture of low abundance cell population using thick electrodes. BIOMICROFLUIDICS 2015; 9:054104. [PMID: 26392836 PMCID: PMC4560720 DOI: 10.1063/1.4928703] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/05/2015] [Indexed: 05/12/2023]
Abstract
Enrichment of rare cell populations such as Circulating Tumor Cells (CTCs) is a critical step before performing analysis. This paper presents a polymeric microfluidic device with integrated thick Carbon-PolyDimethylSiloxane composite (C-PDMS) electrodes designed to carry out dielectrophoretic (DEP) trapping of low abundance biological cells. Such conductive composite material presents advantages over metallic structures. Indeed, as it combines properties of both the matrix and doping particles, C-PDMS allows the easy and fast integration of conductive microstructures using a soft-lithography approach while preserving O2 plasma bonding properties of PDMS substrate and avoiding a cumbersome alignment procedure. Here, we first performed numerical simulations to demonstrate the advantage of such thick C-PDMS electrodes over a coplanar electrode configuration. It is well established that dielectrophoretic force ([Formula: see text]) decreases quickly as the distance from the electrode surface increases resulting in coplanar configuration to a low trapping efficiency at high flow rate. Here, we showed quantitatively that by using electrodes as thick as a microchannel height, it is possible to extend the DEP force influence in the whole volume of the channel compared to coplanar electrode configuration and maintaining high trapping efficiency while increasing the throughput. This model was then used to numerically optimize a thick C-PDMS electrode configuration in terms of trapping efficiency. Then, optimized microfluidic configurations were fabricated and tested at various flow rates for the trapping of MDA-MB-231 breast cancer cell line. We reached trapping efficiencies of 97% at 20 μl/h and 78.7% at 80 μl/h, for 100 μm thick electrodes. Finally, we applied our device to the separation and localized trapping of CTCs (MDA-MB-231) from a red blood cells sample (concentration ratio of 1:10).
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Affiliation(s)
- Julien Marchalot
- Institut des Nanotechnologies de Lyon (INL), CNRS UMR 5270, Université de Lyon 1, Université de Lyon , Villeurbanne F-69622, France
| | - Jean-François Chateaux
- Institut des Nanotechnologies de Lyon (INL), CNRS UMR 5270, Université de Lyon 1, Université de Lyon , Villeurbanne F-69622, France
| | - Magalie Faivre
- Institut des Nanotechnologies de Lyon (INL), CNRS UMR 5270, Université de Lyon 1, Université de Lyon , Villeurbanne F-69622, France
| | - Hichem C Mertani
- Centre de Recherche en Cancérologie de Lyon (CRCL), Centre Léon Bérard, INSERM U1052-CNRS UMR5286, Université de Lyon 1, Université de Lyon , Lyon 69008, France
| | - Rosaria Ferrigno
- Institut des Nanotechnologies de Lyon (INL), CNRS UMR 5270, Université de Lyon 1, Université de Lyon , Villeurbanne F-69622, France
| | - Anne-Laure Deman
- Institut des Nanotechnologies de Lyon (INL), CNRS UMR 5270, Université de Lyon 1, Université de Lyon , Villeurbanne F-69622, France
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Iliescu C, Mărculescu C, Venkataraman S, Languille B, Yu H, Tresset G. On-chip controlled surfactant-DNA coil-globule transition by rapid solvent exchange using hydrodynamic flow focusing. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:13125-13136. [PMID: 25351469 DOI: 10.1021/la5035382] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This paper presents a microfluidic method for precise control of the size and polydispersity of surfactant-DNA nanoparticles. A mixture of surfactant and DNA dispersed in 35% ethanol is focused between two streams of pure water in a microfluidic channel. As a result, a rapid change of solvent quality takes place in the central stream, and the surfactant-bound DNA molecules undergo a fast coil-globule transition. By adjusting the concentrations of DNA and surfactant, fine-tuning of the nanoparticle size, down to a hydrodynamic diameter of 70 nm with a polydispersity index below 0.2, can be achieved with a good reproducibility.
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Affiliation(s)
- Ciprian Iliescu
- Institute of Bioengineering and Nanotechnology , 31 Biopolis Way, The Nanos #04-01, Singapore 138669, Singapore
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9
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Ye T, Li H, Lam KY. Two-dimensional numerical modeling for separation of deformable cells using dielectrophoresis. Electrophoresis 2014; 36:378-85. [DOI: 10.1002/elps.201400251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 05/19/2014] [Accepted: 06/09/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Ting Ye
- School of Mechanical and Aerospace Engineering; Nanyang Technological University; Singapore Singapore
| | - Hua Li
- School of Mechanical and Aerospace Engineering; Nanyang Technological University; Singapore Singapore
| | - K. Y. Lam
- School of Mechanical and Aerospace Engineering; Nanyang Technological University; Singapore Singapore
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10
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Luo J, Nelson EL, Li GP, Bachman M. Microfluidic dielectrophoretic sorter using gel vertical electrodes. BIOMICROFLUIDICS 2014; 8:034105. [PMID: 24926390 PMCID: PMC4032422 DOI: 10.1063/1.4880244] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 05/16/2014] [Indexed: 05/12/2023]
Abstract
We report the development and results of a two-step method for sorting cells and small particles in a microfluidic device. This approach uses a single microfluidic channel that has (1) a microfabricated sieve which efficiently focuses particles into a thin stream, followed by (2) a dielectrophoresis (DEP) section consisting of electrodes along the channel walls for efficient continuous sorting based on dielectric properties of the particles. For our demonstration, the device was constructed of polydimethylsiloxane, bonded to a glass surface, and conductive agarose gel electrodes. Gold traces were used to make electrical connections to the conductive gel. The device had several novel features that aided performance of the sorting. These included a sieving structure that performed continuous displacement of particles into a single stream within the microfluidic channel (improving the performance of downstream DEP, and avoiding the need for additional focusing flow inlets), and DEP electrodes that were the full height of the microfluidic walls ("vertical electrodes"), allowing for improved formation and control of electric field gradients in the microfluidic device. The device was used to sort polymer particles and HeLa cells, demonstrating that this unique combination provides improved capability for continuous DEP sorting of particles in a microfluidic device.
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Affiliation(s)
- Jason Luo
- Department of Biomedical Engineering, University of California, Irvine, California 92697, USA
| | - Edward L Nelson
- Department of Medicine, Institute for Immunology, University of California, Irvine, California 92697, USA
| | - G P Li
- Department of Electrical Engineering and Computer Science, University of California, Irvine, California 92697, USA
| | - Mark Bachman
- Department of Biomedical Engineering, University of California, Irvine, California 92697, USA ; Department of Electrical Engineering and Computer Science, University of California, Irvine, California 92697, USA
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Lewpiriyawong N, Yang C. Dielectrophoresis Field-Flow Fractionation for Continuous-Flow Separation of Particles and Cells in Microfluidic Devices. ADVANCES IN TRANSPORT PHENOMENA 2011 2014. [DOI: 10.1007/978-3-319-01793-8_2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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12
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Cima I, Wen Yee C, Iliescu FS, Phyo WM, Lim KH, Iliescu C, Tan MH. Label-free isolation of circulating tumor cells in microfluidic devices: Current research and perspectives. BIOMICROFLUIDICS 2013; 7:11810. [PMID: 24403992 PMCID: PMC3568085 DOI: 10.1063/1.4780062] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 12/17/2012] [Indexed: 05/04/2023]
Abstract
This review will cover the recent advances in label-free approaches to isolate and manipulate circulating tumor cells (CTCs). In essence, label-free approaches do not rely on antibodies or biological markers for labeling the cells of interest, but enrich them using the differential physical properties intrinsic to cancer and blood cells. We will discuss technologies that isolate cells based on their biomechanical and electrical properties. Label-free approaches to analyze CTCs have been recently invoked as a valid alternative to "marker-based" techniques, because classical epithelial and tumor markers are lost on some CTC populations and there is no comprehensive phenotypic definition for CTCs. We will highlight the advantages and drawbacks of these technologies and the status on their implementation in the clinics.
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Affiliation(s)
- Igor Cima
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos #04-01, Singapore 138669
| | - Chay Wen Yee
- National Cancer Centre Singapore, 11 Hospital Drive, Singapore 169610
| | | | - Wai Min Phyo
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos #04-01, Singapore 138669
| | - Kiat Hon Lim
- Department of Pathology, Singapore General Hospital, Outram Road, Singapore 169608
| | - Ciprian Iliescu
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos #04-01, Singapore 138669
| | - Min Han Tan
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos #04-01, Singapore 138669 ; National Cancer Centre Singapore, 11 Hospital Drive, Singapore 169610
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Iliescu C, Taylor H, Avram M, Miao J, Franssila S. A practical guide for the fabrication of microfluidic devices using glass and silicon. BIOMICROFLUIDICS 2012; 6:16505-1650516. [PMID: 22662101 PMCID: PMC3365353 DOI: 10.1063/1.3689939] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Accepted: 02/08/2012] [Indexed: 05/04/2023]
Abstract
This paper describes the main protocols that are used for fabricating microfluidic devices from glass and silicon. Methods for micropatterning glass and silicon are surveyed, and their limitations are discussed. Bonding methods that can be used for joining these materials are summarized and key process parameters are indicated. The paper also outlines techniques for forming electrical connections between microfluidic devices and external circuits. A framework is proposed for the synthesis of a complete glass/silicon device fabrication flow.
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Jen CP, Chen WF. An insulator-based dielectrophoretic microdevice for the simultaneous filtration and focusing of biological cells. BIOMICROFLUIDICS 2011; 5:44105-4410511. [PMID: 22662057 PMCID: PMC3364804 DOI: 10.1063/1.3658644] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 10/17/2011] [Indexed: 05/05/2023]
Abstract
Manipulating and discriminating biological cells of interest using microfluidic and micro total analysis system (μTAS) devices have potential applications in clinical diagnosis and medicine. Cellular focusing in microfluidic devices is a prerequisite for medical applications, such as cell sorting, cell counting, or flow cytometry. In the present study, an insulator-based dielectrophoretic microdevice is designed for the simultaneous filtration and focusing of biological cells. The cells are introduced into the microchannel and hydrodynamically pre-confined by funnel-shaped insulating structures close to the inlet. There are ten sets of X-patterned insulating structures in the microfluidic channel. The main function of the first five sets of insulating structures is to guide the cells by negative dielectrophoretic responses (viable HeLa cells) into the center region of the microchannel. The positive dielectrophoretic cells (dead HeLa cells) are attracted to regions with a high electric-field gradient generated at the edges of the insulating structures. The remaining five sets of insulating structures are mainly used to focus negative dielectrophoretic cells that have escaped from the upstream region. Experiments employing a mixture of dead and viable HeLa cells are conducted to demonstrate the effectiveness of the proposed design. The results indicate that the performance of both filtration and focusing improves with the increasing strength of the applied electric field and a decreasing inlet sample flow rate, which agrees with the trend predicted by the numerical simulations. The filtration efficiency, which is quantitatively investigated, is up to 88% at an applied voltage of 50 V peak-to-peak (1 kHz) and a sample flow rate of 0.5 μl/min. The proposed device can focus viable cells into a single file using a voltage of 35 V peak-to-peak (1 kHz) at a sample flow rate of 1.0 μl/min.
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Affiliation(s)
- Chun-Ping Jen
- Department of Mechanical Engineering and Advanced Institute of Manufacturing for High-Tech Innovations, National Chung Cheng University, Chia Yi, Taiwan
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Lewpiriyawong N, Kandaswamy K, Yang C, Ivanov V, Stocker R. Microfluidic characterization and continuous separation of cells and particles using conducting poly(dimethyl siloxane) electrode induced alternating current-dielectrophoresis. Anal Chem 2011; 83:9579-85. [PMID: 22035423 DOI: 10.1021/ac202137y] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This paper presents a poly(dimethyl siloxane) (PDMS) polymer microfluidic device using alternating current (ac) dielectrophoresis (DEP) for separating live cells from interfering particles of similar sizes by their polarizabilities under continuous flow and for characterizing DEP behaviors of cells in stagnant flow. The ac-DEP force is generated by three-dimensional (3D) conducting PDMS composite electrodes fabricated on a sidewall of the device main channel. Such 3D PDMS composite electrodes are made by dispersing microsized silver (Ag) fillers into PDMS gel. The sidewall AgPDMS electrodes can generate a 3D electric field that uniformly distributes throughout the channel height and varies along the channel lateral direction, thereby producing stronger lateral DEP effects over the entire channel. This allows not only easy observation of cell/particle lateral motion but also using the lateral DEP force for manipulation of cells/particles. The former feature is used to characterize the frequency-dependent DEP behaviors of Saccharomyces cerevisiae (yeast) and Escherichia coli (bacteria). The latter is utilized for continuous separation of live yeast and bacterial cells from similar-size latex particles as well as live yeast cells from dead yeast cells. The separation efficiency of 97% is achieved in all cases. The demonstration of these functions shows promising applications of the microfluidic device.
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Affiliation(s)
- Nuttawut Lewpiriyawong
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
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Hu N, Yang J, Qian S, Joo SW, Zheng X. A cell electrofusion microfluidic device integrated with 3D thin-film microelectrode arrays. BIOMICROFLUIDICS 2011; 5:34121-3412112. [PMID: 22662046 PMCID: PMC3364834 DOI: 10.1063/1.3630125] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 08/03/2011] [Indexed: 05/07/2023]
Abstract
A microfluidic device integrated with 3D thin film microelectrode arrays wrapped around serpentine-shaped microchannel walls has been designed, fabricated and tested for cell electrofusion. Each microelectrode array has 1015 discrete microelectrodes patterned on each side wall, and the adjacent microelectrodes are separated by coplanar dielectric channel wall. The device was tested to electrofuse K562 cells under a relatively low voltage. Under an AC electric field applied between the pair of the microelectrode arrays, cells are paired at the edge of each discrete microelectrode due to the induced positive dielectrophoresis. Subsequently, electric pulse signals are sequentially applied between the microelectrode arrays to induce electroporation and electrofusion. Compared to the design with thin film microelectrode arrays deposited at the bottom of the side walls, the 3D thin film microelectrode array could induce electroporation and electrofusion under a lower voltage. The staggered electrode arrays on opposing side walls induce inhomogeneous electric field distribution, which could avoid multi-cell fusion. The alignment and pairing efficiencies of K562 cells in this device were 99% and 70.7%, respectively. The electric pulse of low voltage (∼9 V) could induce electrofusion of these cells, and the fusion efficiency was about 43.1% of total cells loaded into the device, which is much higher than that of the convectional and most existing microfluidics-based electrofusion devices.
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Choudhury D, Mo X, Iliescu C, Tan LL, Tong WH, Yu H. Exploitation of physical and chemical constraints for three-dimensional microtissue construction in microfluidics. BIOMICROFLUIDICS 2011; 5:22203. [PMID: 21799710 PMCID: PMC3145229 DOI: 10.1063/1.3593407] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2011] [Accepted: 05/02/2011] [Indexed: 05/06/2023]
Abstract
There are a plethora of approaches to construct microtissues as building blocks for the repair and regeneration of larger and complex tissues. Here we focus on various physical and chemical trapping methods for engineering three-dimensional microtissue constructs in microfluidic systems that recapitulate the in vivo tissue microstructures and functions. Advances in these in vitro tissue models have enabled various applications, including drug screening, disease or injury models, and cell-based biosensors. The future would see strides toward the mesoscale control of even finer tissue microstructures and the scaling of various designs for high throughput applications. These tools and knowledge will establish the foundation for precision engineering of complex tissues of the internal organs for biomedical applications.
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Sancho M, Martínez G, Muñoz S, Sebastián JL, Pethig R. Interaction between cells in dielectrophoresis and electrorotation experiments. BIOMICROFLUIDICS 2010; 4:022802. [PMID: 20697598 PMCID: PMC2917873 DOI: 10.1063/1.3454129] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Accepted: 05/25/2010] [Indexed: 05/11/2023]
Abstract
Progress in microelectrode-based technologies has facilitated the development of sophisticated methods for manipulating and separating cells, bacteria, and other bioparticles. For many of these various applications, the theoretical modeling of the electrical response of compartmentalized particles to an external field is important. In this paper we address the analysis of the interaction between cells immersed in rf fields. We use an integral formulation of the problem derived from a consideration of the charge densities induced at the interfaces of the particle compartments. The numerical solution by a boundary element technique allows characterization of their dielectric properties. Experimental validation of this theoretical model is obtained by investigating two effects: (1) The influence that dipolar "pearl chaining" has on the dielectrophoretic behavior of human T lymphocytes and (2) the frequency variation of the spin and orbital torques of approaching insulinoma beta-cells in a rotating field.
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Inglis DW, Herman N, Vesey G. Highly accurate deterministic lateral displacement device and its application to purification of fungal spores. BIOMICROFLUIDICS 2010; 4:024109. [PMID: 20697580 PMCID: PMC2917885 DOI: 10.1063/1.3430553] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 04/23/2010] [Indexed: 05/07/2023]
Abstract
We have designed, built, and evaluated a microfluidic device that uses deterministic lateral displacement for size-based separation. The device achieves almost 100% purity and recovery in continuously sorting two, four, and six micrometer microspheres. We have applied this highly efficient device to the purification of fungal (Aspergillus) spores that are spherical ( approximately 4 mum diameter) with a narrow size distribution. Such separation directly from culture using unfiltered A. niger suspensions is difficult due to a high level of debris. The device produces a two to three increase in the ratio of spores to debris as measured by light scatter in a flow cytometer. The procedure is feasible at densities up to 4.4x10(6) sporesml. This is one of the first studies to apply microfluidic techniques to spore separations and has demonstrated that a passive separation system could significantly reduce the amount of debris in a suspension of fungal spores with virtually no loss of spore material.
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