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Nguyen TH, Nguyen HA, Tran Thi YV, Hoang Tran D, Cao H, Chu Duc T, Bui TT, Do Quang L. Concepts, electrode configuration, characterization, and data analytics of electric and electrochemical microfluidic platforms: a review. Analyst 2023; 148:1912-1929. [PMID: 36928639 DOI: 10.1039/d2an02027k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Microfluidic cytometry (MC) and electrical impedance spectroscopy (EIS) are two important techniques in biomedical engineering. Microfluidic cytometry has been utilized in various fields such as stem cell differentiation and cancer metastasis studies, and provides a simple, label-free, real-time method for characterizing and monitoring cellular fates. The impedance microdevice, including impedance flow cytometry (IFC) and electrical impedance spectroscopy (EIS), is integrated into MC systems. IFC measures the impedance of individual cells as they flow through a microfluidic device, while EIS measures impedance changes during binding events on electrode regions. There have been significant efforts to improve and optimize these devices for both basic research and clinical applications, based on the concepts, electrode configurations, and cell fates. This review outlines the theoretical concepts, electrode engineering, and data analytics of these devices, and highlights future directions for development.
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Affiliation(s)
- Thu Hang Nguyen
- University of Engineering and Technology, Vietnam National University, Hanoi, Vietnam.
| | | | - Y-Van Tran Thi
- University of Science, Vietnam National University, Hanoi, Vietnam.
| | | | - Hung Cao
- University of California, Irvine, USA
| | - Trinh Chu Duc
- University of Engineering and Technology, Vietnam National University, Hanoi, Vietnam.
| | - Tung Thanh Bui
- University of Engineering and Technology, Vietnam National University, Hanoi, Vietnam.
| | - Loc Do Quang
- University of Science, Vietnam National University, Hanoi, Vietnam.
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2
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Alazzam A, Al-Khaleel M, Riahi MK, Mathew B, Gawanmeh A, Nerguizian V. Dielectrophoresis Multipath Focusing of Microparticles through Perforated Electrodes in Microfluidic Channels. BIOSENSORS-BASEL 2019; 9:bios9030099. [PMID: 31394810 PMCID: PMC6784380 DOI: 10.3390/bios9030099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 07/25/2019] [Accepted: 08/02/2019] [Indexed: 11/16/2022]
Abstract
This paper presents focusing of microparticles in multiple paths within the direction of the flow using dielectrophoresis. The focusing of microparticles is realized through partially perforated electrodes within the microchannel. A continuous electrode on the top surface of the microchannel is considered, while the bottom side is made of a circular meshed perforated electrode. For the mathematical model of this microfluidic channel, inertia, buoyancy, drag and dielectrophoretic forces are brought up in the motion equation of the microparticles. The dielectrophoretic force is accounted for through a finite element discretization taking into account the perforated 3D geometry within the microchannel. An ordinary differential equation is solved to track the trajectories of the microparticles. For the case of continuous electrodes using the same mathematical model, the numerical simulation shows a very good agreement with the experiments, and this confirms the validation of focusing of microparticles within the proposed perforated electrode microchannel. Microparticles of silicon dioxide and polystyrene are used for this analysis. Their initial positions and radius, the Reynolds number, and the radius of the pore in perforated electrodes mainly conduct microparticles trajectories. Moreover, the radius of the pore of perforated electrode is the dominant factor in the steady state levitation height.
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Affiliation(s)
- Anas Alazzam
- Mechanical Engineering Department, Khalifa University, Abu Dhabi 127788, UAE
- Electrical Engineering Department, École de Technologie Supérieure, Montreal, Quebec, QC H3C 1K3, Canada
| | - Mohammad Al-Khaleel
- Department of Applied Mathematics and Sciences, Khalifa University, Abu Dhabi 127788, UAE
- Department of Mathematics, Yarmouk University, Irbid 21163, Jordan
| | - Mohamed Kamel Riahi
- Department of Applied Mathematics and Sciences, Khalifa University, Abu Dhabi 127788, UAE
| | - Bobby Mathew
- Mechanical Engineering Department, United Arab Emirates University, Al Ain 15551, UAE
| | - Amjad Gawanmeh
- Electrical and Computer Engineering Department, Khalifa University, Abu Dhabi 127788, UAE
- Electrical and Computer Engineering Department, Concordia University, Montreal, Quebec, QC H3C 1K3, Canada
| | - Vahé Nerguizian
- Electrical Engineering Department, École de Technologie Supérieure, Montreal, Quebec, QC H3C 1K3, Canada.
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Kotnala A, Zheng Y, Fu J, Cheng W. Microfluidic-based high-throughput optical trapping of nanoparticles. LAB ON A CHIP 2017; 17:2125-2134. [PMID: 28561826 PMCID: PMC5533511 DOI: 10.1039/c7lc00286f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Optical tweezers have emerged as a powerful tool for multiparametric analysis of individual nanoparticles with single-molecule sensitivity. However, its inherent low-throughput characteristic remains a major obstacle to its applications within and beyond the laboratory. This limitation is further exacerbated when working with low concentration nanoparticle samples. Here, we present a microfluidic-based optical tweezers system that can 'actively' deliver nanoparticles to a designated microfluidic region for optical trapping and analysis. The active microfluidic delivery of nanoparticles results in significantly improved throughput and efficiency for optical trapping of nanoparticles. We observed a more than tenfold increase in optical trapping throughput for nanoparticles as compared to conventional systems at the same nanoparticle concentration. To demonstrate the utility of this microfluidic-based optical tweezers system, we further used back-focal plane interferometry coupled with a trapping laser for the precise quantitation of nanoparticle size without prior knowledge of the refractive index of nanoparticles. The development of this microfluidic-based active optical tweezers system thus opens the door to high-throughput multiparametric analysis of nanoparticles using precision optical traps in the future.
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Affiliation(s)
- Abhay Kotnala
- Department of Pharmaceutical Sciences, University of Michigan, 428 church street, Ann Arbor, MI 48109, USA
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4
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Zhao G, Fu J. Microfluidics for cryopreservation. Biotechnol Adv 2017; 35:323-336. [PMID: 28153517 PMCID: PMC6236673 DOI: 10.1016/j.biotechadv.2017.01.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 01/23/2017] [Accepted: 01/25/2017] [Indexed: 11/19/2022]
Abstract
Cryopreservation has utility in clinical and scientific research but implementation is highly complex and includes labor-intensive cell-specific protocols for the addition/removal of cryoprotective agents and freeze-thaw cycles. Microfluidic platforms can revolutionize cryopreservation by providing new tools to manipulate and screen cells at micro/nano scales, which are presently difficult or impossible with conventional bulk approaches. This review describes applications of microfluidic tools in cell manipulation, cryoprotective agent exposure, programmed freezing/thawing, vitrification, and in situ assessment in cryopreservation, and discusses achievements and challenges, providing perspectives for future development.
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Affiliation(s)
- Gang Zhao
- Center for Biomedical Engineering, Department of Electronic Science and Technology, University of Science and Technology of China, Hefei 230027, Anhui, PR China.
| | - Jianping Fu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Michigan Center for Integrative Research in Critical Care, University of Michigan, Ann Arbor, MI 48109, USA
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Bausch CS, Heyn C, Hansen W, Wolf IMA, Diercks BP, Guse AH, Blick RH. Ultra-fast cell counters based on microtubular waveguides. Sci Rep 2017; 7:41584. [PMID: 28134293 PMCID: PMC5278506 DOI: 10.1038/srep41584] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 12/22/2016] [Indexed: 01/29/2023] Open
Abstract
We present a radio-frequency impedance-based biosensor embedded inside a semiconductor microtube for the in-flow detection of single cells. An impedance-matched tank circuit and a tight wrapping of the electrodes around the sensing region, which creates a close, leakage current-free contact between cells and electrodes, yields a high signal-to-noise ratio. We experimentally show a twofold improved sensitivity of our three-dimensional electrode structure to conventional planar electrodes and support these findings by finite element simulations. Finally, we report on the differentiation of polystyrene beads, primary mouse T lymphocytes and Jurkat T lymphocytes using our device.
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Affiliation(s)
- Cornelius S Bausch
- Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstraße 11c, Hamburg, Germany.,Center for Hybrid Nanostructures, University of Hamburg, Falkenried 88, Hamburg, Germany
| | - Christian Heyn
- Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstraße 11c, Hamburg, Germany
| | - Wolfgang Hansen
- Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstraße 11c, Hamburg, Germany
| | - Insa M A Wolf
- Calcium Signaling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, Hamburg, Germany
| | - Björn-Philipp Diercks
- Calcium Signaling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, Hamburg, Germany
| | - Andreas H Guse
- Calcium Signaling Group, Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, Hamburg, Germany
| | - Robert H Blick
- Institute of Nanostructure and Solid State Physics, University of Hamburg, Jungiusstraße 11c, Hamburg, Germany.,Center for Hybrid Nanostructures, University of Hamburg, Falkenried 88, Hamburg, Germany
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6
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Rajauria S, Axline C, Gottstein C, Cleland AN. High-speed discrimination and sorting of submicron particles using a microfluidic device. NANO LETTERS 2015; 15:469-475. [PMID: 25442878 DOI: 10.1021/nl503783p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The size- and fluorescence-based sorting of micro- and nanoscale particles suspended in fluid presents a significant and important challenge for both sample analysis and for manufacturing of nanoparticle-based products. Here, we demonstrate a disposable microfluidic particle sorter that enables high-throughput, on-demand counting and binary sorting of submicron particles and cells using either fluorescence or an electrically based determination of particle size. Size-based sorting uses a resistive pulse sensor integrated on-chip, whereas fluorescence-based discrimination is achieved using on-the-fly optical image capture and analysis. Following detection and analysis, the individual particles are deflected using a pair of piezoelectric actuators, directing the particles into one of two desired output channels; the main flow goes into a third waste channel. The integrated system can achieve sorting fidelities of better than 98%, and the mechanism can successfully count and actuate, on demand, more than 60,000 particles/min.
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Affiliation(s)
- Sukumar Rajauria
- Department of Physics, University of California , Santa Barbara, California 93106, United States
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Song Y, Yang J, Pan X, Li D. High-throughput and sensitive particle counting by a novel microfluidic differential resistive pulse sensor with multidetecting channels and a common reference channel. Electrophoresis 2015; 36:495-501. [DOI: 10.1002/elps.201400427] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 10/25/2014] [Accepted: 10/27/2014] [Indexed: 01/27/2023]
Affiliation(s)
- Yongxin Song
- Department of Marine Engineering; Dalian Maritime University; Dalian China
| | - Jiandong Yang
- Department of Marine Engineering; Dalian Maritime University; Dalian China
| | - Xinxiang Pan
- Department of Marine Engineering; Dalian Maritime University; Dalian China
| | - Dongqing Li
- Department of Mechanical and Mechatronics Engineering; University of Waterloo; Waterloo Canada
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Hassan U, Bashir R. Coincidence detection of heterogeneous cell populations from whole blood with coplanar electrodes in a microfluidic impedance cytometer. LAB ON A CHIP 2014; 14:4370-81. [PMID: 25231594 DOI: 10.1039/c4lc00879k] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Particle counting finds many industrial applications especially in medical healthcare. In particular, cell counting from whole blood is used pervasively for disease diagnostics. Microfluidic impedance cytometry is fast, requires a small volume of blood, can be used at point of care and can perform absolute enumeration of different cell types in the sample. Coincidence detection is very essential for accurate counting results and becomes more significant while counting specific target cells, e.g. CD4(+) or CD8(+) T cell count in HIV/AIDS patient blood samples. In heterogeneous samples, e.g. blood, cell differentiation for all coincidence occurrences is essential in addition to the coincidence detection for accurate cell enumeration. In this paper, we have characterized the coincidence detection with cell differentiation using a microfluidic impedance biochip. The pure population of leukocytes is obtained after all erythrocytes are lysed on-chip from whole blood. Leukocytes were counted electrically as they pass over coplanar microfabricated electrodes bonded to the 15 μm × 15 μm cross section counting channel while generating a bipolar pulse for each cell passage. We have developed a mathematical model to simulate the electrical cell pulse and its coincidences. We show that coincidence detection can be characterized into three main types based on the range of time delay at which the coincidence occurs. We have also characterized cell differentiation for all the three coincidence types and show that multiple coincidences of different types can also occur. We used healthy and HIV-infected patient blood samples and used our coincidence detection technique to count CD4(+) and CD8(+) T cells and show the improvement in accuracy of cell counts compared to that without coincidence detection. We have also shown the improvement in the erythrocyte counting with coincidence detection in diluted whole blood samples.
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Affiliation(s)
- U Hassan
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, William L. Everitt Laboratory, 1406 W. Green St., Urbana, IL 61801, USA
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Sukas S, Schreuder E, de Wagenaar B, Swennenhuis J, van den Berg A, Terstappen L, Le Gac S. A novel side electrode configuration integrated in fused silica microsystems for synchronous optical and electrical spectroscopy. LAB ON A CHIP 2014; 14:1821-1825. [PMID: 24756127 DOI: 10.1039/c3lc51433a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a novel electrode configuration consisting of coplanar side electrode pairs integrated at the half height of the microchannels for the creation of a homogeneous electric field distribution as well as for synchronous optical and electrical measurements. For the integration of such electrodes in fused silica microsystems, a dedicated microfabrication method was utilized, whereby an intermediate bonding layer was applied to lower the temperature for fusion bonding to avoid thereby metal degradation and subsequently to preserve the electrode structures. Finally, we demonstrate the applicability of our devices with integrated electrodes for single cell electrical lysis and simultaneous fluorescence and impedance measurements for both cell counting and characterization.
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Affiliation(s)
- Sertan Sukas
- BIOS - Lab on a Chip group, MESA+ Institute for Nanotechnology, University of Twente, Enschede, The Netherlands.
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10
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Nikolic-Jaric M, Cabel T, Salimi E, Bhide A, Braasch K, Butler M, Bridges GE, Thomson DJ. Differential electronic detector to monitor apoptosis using dielectrophoresis-induced translation of flowing cells (dielectrophoresis cytometry). BIOMICROFLUIDICS 2013; 7:24101. [PMID: 24404007 PMCID: PMC3598809 DOI: 10.1063/1.4793223] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 02/01/2013] [Indexed: 05/26/2023]
Abstract
The instrument described here is an all-electronic dielectrophoresis (DEP) cytometer sensitive to changes in polarizability of single cells. The important novel feature of this work is the differential electrode array that allows independent detection and actuation of single cells within a short section ([Formula: see text]) of the microfluidic channel. DEP actuation modifies the altitude of the cells flowing between two altitude detection sites in proportion to cell polarizability; changes in altitude smaller than 0.25 μm can be detected electronically. Analysis of individual experimental signatures allows us to make a simple connection between the Clausius-Mossotti factor (CMF) and the amount of vertical cell deflection during actuation. This results in an all-electronic, label-free differential detector that monitors changes in physiological properties of the living cells and can be fully automated and miniaturized in order to be used in various online and offline probes and point-of-care medical applications. High sensitivity of the DEP cytometer facilitates observations of delicate changes in cell polarization that occur at the onset of apoptosis. We illustrate the application of this concept on a population of Chinese hamster ovary (CHO) cells that were followed in their rapid transition from a healthy viable to an early apoptotic state. DEP cytometer viability estimates closely match an Annexin V assay (an early apoptosis marker) on the same population of cells.
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Affiliation(s)
- Marija Nikolic-Jaric
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| | - Tim Cabel
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| | - Elham Salimi
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| | - Ashlesha Bhide
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| | - Katrin Braasch
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Michael Butler
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Greg E Bridges
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
| | - Douglas J Thomson
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
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Segerink LI, Sprenkels AJ, Bomer JG, Vermes I, van den Berg A. A new floating electrode structure for generating homogeneous electrical fields in microfluidic channels. LAB ON A CHIP 2011; 11:1995-2001. [PMID: 21279234 DOI: 10.1039/c0lc00489h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this article a new parallel electrode structure in a microfluidic channel is described that makes use of a floating electrode to get a homogeneous electrical field. Compared to existing parallel electrode structures, the new structure has an easier production process and there is no need for an electrical connection to both sides of the microfluidic chip. With the new chip design, polystyrene beads suspended in background electrolyte have been detected using electrical impedance measurements. The results of electrical impedance changes caused by beads passing the electrodes are compared with results in a similar planar electrode configuration. It is shown that in the new configuration the coefficient of variation of the impedance changes is lower compared to the planar configuration (0.39 versus 0.56) and less dependent on the position of the beads passage in the channel as a result of the homogeneous electrical field. To our knowledge this is the first time that a floating electrode is used for the realization of a parallel electrode structure. The proposed production method for parallel electrodes in microfluidic channels can easily be applied to other applications.
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Affiliation(s)
- Loes I Segerink
- BIOS-Lab on a Chip group, MESA+ Institute for Nanotechnology, University of Twente, P.O. box 217, 7500 AE Enschede, The Netherlands.
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Fraikin JL, Teesalu T, McKenney CM, Ruoslahti E, Cleland AN. A high-throughput label-free nanoparticle analyser. NATURE NANOTECHNOLOGY 2011; 6:308-13. [PMID: 21378975 DOI: 10.1038/nnano.2011.24] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 02/04/2011] [Indexed: 05/11/2023]
Abstract
Synthetic nanoparticles and genetically modified viruses are used in a range of applications, but high-throughput analytical tools for the physical characterization of these objects are needed. Here we present a microfluidic analyser that detects individual nanoparticles and characterizes complex, unlabelled nanoparticle suspensions. We demonstrate the detection, concentration analysis and sizing of individual synthetic nanoparticles in a multicomponent mixture with sufficient throughput to analyse 500,000 particles per second. We also report the rapid size and titre analysis of unlabelled bacteriophage T7 in both salt solution and mouse blood plasma, using just ~1 × 10⁻⁶ l of analyte. Unexpectedly, in the native blood plasma we discover a large background of naturally occurring nanoparticles with a power-law size distribution. The high-throughput detection capability, scalable fabrication and simple electronics of this instrument make it well suited for diverse applications.
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Affiliation(s)
- Jean-Luc Fraikin
- Department of Physics, University of California Santa Barbara, California 93106, USA
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Cheung KC, Di Berardino M, Schade-Kampmann G, Hebeisen M, Pierzchalski A, Bocsi J, Mittag A, Tárnok A. Microfluidic impedance-based flow cytometry. Cytometry A 2010; 77:648-66. [PMID: 20583276 DOI: 10.1002/cyto.a.20910] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microfabricated flow cytometers can detect, count, and analyze cells or particles using microfluidics and electronics to give impedance-based characterization. Such systems are being developed to provide simple, low-cost, label-free, and portable solutions for cell analysis. Recent work using microfabricated systems has demonstrated the capability to analyze micro-organisms, erythrocytes, leukocytes, and animal and human cell lines. Multifrequency impedance measurements can give multiparametric, high-content data that can be used to distinguish cell types. New combinations of microfluidic sample handling design and microscale flow phenomena have been used to focus and position cells within the channel for improved sensitivity. Robust designs will enable focusing at high flowrates while reducing requirements for control over multiple sample and sheath flows. Although microfluidic impedance-based flow cytometers have not yet or may never reach the extremely high throughput of conventional flow cytometers, the advantages of portability, simplicity, and ability to analyze single cells in small populations are, nevertheless, where chip-based cytometry can make a large impact.
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Affiliation(s)
- Karen C Cheung
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada.
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14
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Wu Y, Benson JD, Critser JK, Almasri M. Note: Microelectromechanical systems Coulter counter for cell monitoring and counting. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:076103. [PMID: 20687769 DOI: 10.1063/1.3462327] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This note describes the design, fabrication, and testing of a novel microelectromechanical systems Coulter counter. The Coulter counter will be used to detect and monitor impedance changes of cells as a function of time in response to different experimental extracellular environments. The device consists of SU-8 (negative photoresist) microchannels, vertical electroplated electrodes, polydimethylsiloxane cover, and is divided into a passive mixing region, a focusing region using negative dielectrophoretic forces, and a measuring region defined by multiple electroplated electrode pairs. The devices were tested using both microbeads in saline water and fibroblast cells in phosphate buffered saline solution. The results show that the proposed microsystem is capable of monitoring impedance of cells at different positions along the Coulter microchannel.
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Affiliation(s)
- Yifan Wu
- Department of Electrical and Computer Engineering, University of Missouri, Columbia, Missouri 65211, USA
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15
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Segerink LI, Sprenkels AJ, ter Braak PM, Vermes I, van den Berg A. On-chip determination of spermatozoa concentration using electrical impedance measurements. LAB ON A CHIP 2010; 10:1018-1024. [PMID: 20358109 DOI: 10.1039/b923970g] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this article we describe the development of a microfluidic chip to determine the concentration of spermatozoa in semen, which is a main quality parameter for the fertility of a man. A microfluidic glass-glass chip is used, consisting of a microchannel with a planar electrode pair that allows the detection of spermatozoa passing the electrodes using electrical impedance measurements. Cells other than spermatozoa in semen also cause a change in impedance when passing the electrodes, interfering with the spermatozoa count. We demonstrate that the change in electrical impedance is related to the size of cells passing the electrodes, allowing to distinguish between spermatozoa and HL-60 cells suspended in washing medium. In the same way we are able to distinguish between polystyrene beads and spermatozoa. Thus, by adding a known concentration of polystyrene beads to a boar semen sample, the spermatozoa concentrations of seven mixtures are measured and show a good correlation with the actual concentration (R(2)-value = 0.97). To our knowledge this is the first time that the concentration of spermatozoa has been determined on chip using electrical impedance measurements without a need to know the actual flow speed. The proposed method to determine the concentration can be easily applied to other cells. The described on-chip determination of the spermatozoa concentration is a first step towards a microfluidic system for a complete quality analysis of semen.
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Affiliation(s)
- Loes I Segerink
- BIOS - the Lab-on-a-Chip group, MESA+ Institute of Nanotechnology, University of Twente, AE Enschede, The Netherlands.
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16
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Ferrier GA, Romanuik SF, Thomson DJ, Bridges GE, Freeman MR. A microwave interferometric system for simultaneous actuation and detection of single biological cells. LAB ON A CHIP 2009; 9:3406-3412. [PMID: 19904408 DOI: 10.1039/b908974h] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In biomedical applications ranging from the study of pathogen invasion to drug efficacy assays, there is a growing need to develop minimally invasive techniques for single-cell analysis. This has inspired researchers to develop optical, electrical, microelectromechanical and microfluidic devices for exploring phenomena at the single-cell level. In this work, we demonstrate an electrical approach for single-cell analysis wherein a 1.6 GHz microwave interferometer detects the capacitance changes (DeltaC) produced by single cells flowing past a coplanar interdigitated electrode pair. The experimental and simulated capacitance changes generated by yeast cells are in close agreement. By using the capacitance changes of uniform polystyrene spheres (diameter = 5.7 microm) for calibration purposes, we demonstrate a 0.65 aF sensitivity in a 10 ms response time. Using an RC circuit, a low frequency sinusoidal potential is simultaneously superimposed on the electrode pair to generate a dielectrophoretic force that translates cells. Specifically, when yeast cells suspended in a solution of 90 ppm NaCl in deionized water are exposed to 10 kHz and 3 MHz potentials (ranging from 1-3 V(pp)), they experience negative and positive dielectrophoresis, respectively. The corresponding changes in cell elevation above the interdigitated electrodes are detected using the asymmetry of the capacitance signature produced by the cell. Cell elevation changes can be detected in less than 80 ms. The minimum detectable change in elevation is estimated to be 0.22 microm. This approach will have applications in rapid single-cell dielectrophoretic analysis, and may also prove useful in conjunction with impedance spectroscopy.
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Affiliation(s)
- Graham A Ferrier
- Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
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Requa MV, Fraikin JL, Stanton MA, Cleland AN. Nanoscale radiofrequency impedance sensors with unconditionally stable tuning. JOURNAL OF APPLIED PHYSICS 2009; 106:74308. [PMID: 19902001 PMCID: PMC2774346 DOI: 10.1063/1.3243315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 09/09/2009] [Indexed: 05/28/2023]
Abstract
Impedance sensors perform an important role in a number of biosensing applications, including particle counting, sizing, and velocimetry. Detection of nanoparticles, or changes in, e.g., the interfacial Debye-Hückel layer, can also be performed using nanoscale impedance sensors. One method for monitoring changes in the local impedance is to use radiofrequency reflectometry, which when combined with an impedance-matched sensor can afford very high sensitivity with very large detection bandwidth. Maintaining sensitivity and dynamic range, however, requires continuous tuning of the impedance matching network. Here we demonstrate a dual feedback tuning circuit, which allows us to maintain near-perfect impedance matching, even in the presence of long-term drifts in sensor impedance. We apply this tuning technique to a nanoscale interdigitated impedance sensor, designed to allow the direct detection of nanoparticles or real-time monitoring of molecular surface binding. We demonstrate optimal performance of the nanoscale sensor and tuned impedance network both when modulating the concentration of saline to which the sensor is exposed and when electronically switching between sensors configured in a two-element differential array, achieving a stabilization response time of <20 ms.
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Nikolic-Jaric M, Romanuik SF, Ferrier GA, Bridges GE, Butler M, Sunley K, Thomson DJ, Freeman MR. Microwave frequency sensor for detection of biological cells in microfluidic channels. BIOMICROFLUIDICS 2009; 3:34103. [PMID: 20216959 PMCID: PMC2835277 DOI: 10.1063/1.3187149] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Accepted: 07/06/2009] [Indexed: 05/10/2023]
Abstract
We present details of an apparatus for capacitive detection of biomaterials in microfluidic channels operating at microwave frequencies where dielectric effects due to interfacial polarization are minimal. A circuit model is presented, which can be used to adapt this detection system for use in other microfluidic applications and to identify ones where it would not be suitable. The detection system is based on a microwave coupled transmission line resonator integrated into an interferometer. At 1.5 GHz the system is capable of detecting changes in capacitance of 650 zF with a 50 Hz bandwidth. This system is well suited to the detection of biomaterials in a variety of suspending fluids, including phosphate-buffered saline. Applications involving both model particles (polystyrene microspheres) and living cells-baker's yeast (Saccharomyces cerevisiae) and Chinese hamster ovary cells-are presented.
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Fraikin JL, Requa MV, Cleland AN. Probing the debye layer: capacitance and potential of zero charge measured using a debye-layer transistor. PHYSICAL REVIEW LETTERS 2009; 102:156601. [PMID: 19518661 DOI: 10.1103/physrevlett.102.156601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Indexed: 05/27/2023]
Abstract
We present a unique method for probing the properties of the electrolytic Debye layer, incorporating it as the active element in a novel radio frequency (rf) field-effect transistor. The capacitance of the Debye layer depends nonlinearly on the voltage applied across it, and we exploit this dependence to directly modulate the rf conductance between two nanofabricated interdigitated electrodes. We make quantitative measurements of the Debye-layer capacitance, allowing us to determine the potential of zero charge, a quantity of importance for electrochemistry and impedance-based biosensing.
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Affiliation(s)
- J-L Fraikin
- Department of Physics, University of California, Santa Barbara, California, USA
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Scott R, Sethu P, Harnett CK. Three-dimensional hydrodynamic focusing in a microfluidic Coulter counter. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:046104. [PMID: 18447562 DOI: 10.1063/1.2900010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Electrical impedance-based particle detection or Coulter counting, offers a lab-on-chip compatible method for flow cytometry. Developments in this area will produce devices with greater portability, lower cost, and lower power requirements than fluorescence-based flow cytometry. Because conventional Coulter apertures are prone to clogging, hydrodynamic focusing improves the device by creating fluid-walled channels with variable width to increase sensitivity without the associated risk of blocking the channel. We describe a device that focuses the sample in three dimensions, creating a narrow sample stream on the floor of the channel for close interaction with sensing electrodes. The key to this design is a stepped outlet channel fabricated in a single layer with soft lithography. In contrast to previous impedance-based designs, the new design requires minimal alignment with the substrate. Three-dimensional focusing maximizes the sensitivity of the device to cell-size particles within much larger channels. Impedance-based particle sensing experiments within this device show an increase in percentage conductivity change by a factor of 2.5 over devices that only focus the sample in the horizontal direction.
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Affiliation(s)
- R Scott
- Electrical and Computer Engineering Department, University of Louisville, Louisville, Kentucky 40208, USA
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