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Hu Z, Zhao W, Chen Y, Han Y, Zhang C, Feng X, Jing G, Wang K, Bai J, Wang G, Zhao W. Onset of Nonlinear Electroosmotic Flow under an AC Electric Field. Anal Chem 2022; 94:17913-17921. [PMID: 36519957 DOI: 10.1021/acs.analchem.2c03891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Nonlinearity of electroosmotic flows (EOFs) is ubiquitous and plays a crucial role in ion transport, specimen mixing, electrochemistry reaction, and electric energy storage and utilization. When and how the transition from a linear regime to a nonlinear one occurs is essential for understanding, prohibiting, or utilizing nonlinear EOF. However, due to the lack of reliable experimental instruments with high spatial and temporal resolutions, the investigation of the onset of nonlinear EOF still remains in theory. Herein, we experimentally studied the velocity fluctuations of EOFs driven by an alternating current (AC) electric field via ultrasensitive fluorescent blinking tricks. The linear and nonlinear AC EOFs are successfully identified from both the time trace and energy spectra of velocity fluctuations. The transitional electric field (EA,C) is determined by both the convection velocity (U) and AC frequency (ff) as EA,C ∼ ff0.48-0.027U. We hope the current investigation could be essential in the development of both theory and applications of nonlinear EOFs.
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Affiliation(s)
- Zhongyan Hu
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi'an710127, China
| | | | - Yu Chen
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi'an710127, China
| | - Yu Han
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi'an710127, China
| | - Chen Zhang
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi'an710127, China
| | - Xiaoqiang Feng
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi'an710127, China
| | - Guangyin Jing
- School of Physics, Northwest University, Xi'an710127, China
| | - Kaige Wang
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi'an710127, China
| | - Jintao Bai
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi'an710127, China
| | - Guiren Wang
- Department of Mechanical Engineering & Biomedical Engineering Program, University of South Carolina, Columbia, South Carolina29208, United States
| | - Wei Zhao
- State Key Laboratory of Photon-Technology in Western China Energy, International Collaborative Center on Photoelectric Technology and Nano Functional Materials, Institute of Photonics & Photon Technology, Northwest University, Xi'an710127, China
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2
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Hu Z, Zhao T, Zhao W, Yang F, Wang H, Wang K, Bai J, Wang G. Transition from periodic to chaotic
AC
electroosmotic flows near electric double layer. AIChE J 2021. [DOI: 10.1002/aic.17148] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Zhongyan Hu
- State Key Laboratory of Photon‐Technology in Western China Energy, International Scientific and Technological Cooperation Base of Photoelectric Technology and Functional Materials and Application, Institute of Photonics and Photon‐Technology Northwest University Xi'an 710127 China
| | - Tianyun Zhao
- School of Automation Northwestern Polytechnical University Xi'an China
| | - Wei Zhao
- State Key Laboratory of Photon‐Technology in Western China Energy, International Scientific and Technological Cooperation Base of Photoelectric Technology and Functional Materials and Application, Institute of Photonics and Photon‐Technology Northwest University Xi'an 710127 China
- Department of Mechanical Engineering & Biomedical Engineering Program University of South Carolina Columbia South Carolina USA
| | - Fang Yang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education Jilin University Changchun P.R. China
| | - Hongxun Wang
- Aeronautics Engineering College Air Force Engineering University Xi'an China
| | - Kaige Wang
- State Key Laboratory of Photon‐Technology in Western China Energy, International Scientific and Technological Cooperation Base of Photoelectric Technology and Functional Materials and Application, Institute of Photonics and Photon‐Technology Northwest University Xi'an 710127 China
| | - Jintao Bai
- State Key Laboratory of Photon‐Technology in Western China Energy, International Scientific and Technological Cooperation Base of Photoelectric Technology and Functional Materials and Application, Institute of Photonics and Photon‐Technology Northwest University Xi'an 710127 China
| | - Guiren Wang
- State Key Laboratory of Photon‐Technology in Western China Energy, International Scientific and Technological Cooperation Base of Photoelectric Technology and Functional Materials and Application, Institute of Photonics and Photon‐Technology Northwest University Xi'an 710127 China
- Department of Mechanical Engineering & Biomedical Engineering Program University of South Carolina Columbia South Carolina USA
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3
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Salari A, Navi M, Lijnse T, Dalton C. AC Electrothermal Effect in Microfluidics: A Review. MICROMACHINES 2019; 10:E762. [PMID: 31717932 PMCID: PMC6915365 DOI: 10.3390/mi10110762] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 10/27/2019] [Accepted: 10/28/2019] [Indexed: 02/06/2023]
Abstract
The electrothermal effect has been investigated extensively in microfluidics since the 1990s and has been suggested as a promising technique for fluid manipulations in lab-on-a-chip devices. The purpose of this article is to provide a timely overview of the previous works conducted in the AC electrothermal field to provide a comprehensive reference for researchers new to this field. First, electrokinetic phenomena are briefly introduced to show where the electrothermal effect stands, comparatively, versus other mechanisms. Then, recent advances in the electrothermal field are reviewed from different aspects and categorized to provide a better insight into the current state of the literature. Results and achievements of different studies are compared, and recommendations are made to help researchers weigh their options and decide on proper configuration and parameters.
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Affiliation(s)
- Alinaghi Salari
- Biomedical Engineering Graduate Program, Ryerson University, Toronto, ON M5B 2K3, Canada;
- Institute for Biomedical Engineering, Science and Technology (iBEST), St. Michael’s Hospital, Toronto, ON M5B 1T8, Canada
- Keenan Research Centre, St. Michael’s Hospital, Toronto, ON M5B 1T8, Canada
| | - Maryam Navi
- Biomedical Engineering Graduate Program, Ryerson University, Toronto, ON M5B 2K3, Canada;
- Institute for Biomedical Engineering, Science and Technology (iBEST), St. Michael’s Hospital, Toronto, ON M5B 1T8, Canada
- Keenan Research Centre, St. Michael’s Hospital, Toronto, ON M5B 1T8, Canada
| | - Thomas Lijnse
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, AB T2N 1N4, Canada;
| | - Colin Dalton
- Biomedical Engineering Graduate Program, University of Calgary, Calgary, AB T2N 1N4, Canada;
- Electrical and Computer Engineering Department, University of Calgary, Calgary, AB T2N 1N4, Canada
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4
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Wu Z, Cai H, Ao Z, Nunez A, Liu H, Bondesson M, Guo S, Guo F. A Digital Acoustofluidic Pump Powered by Localized Fluid-Substrate Interactions. Anal Chem 2019; 91:7097-7103. [PMID: 31083981 DOI: 10.1021/acs.analchem.9b00069] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The precise transportation of small-volume liquids in microfluidic and nanofluidic systems remains a challenge for many applications, such as clinical fluidical analysis. Here, we present a reliable digital pump that utilizes acoustic streaming induced by localized fluid-substrate interactions. By locally generating streaming via a C-shaped interdigital transducer (IDT) within a triangle-edged microchannel, our acoustofluidic pump can generate a stable unidirectional flow (∼nanoliter per second flow rate) with a precise digital regulation (∼second response time), and it is capable of handling aqueous solutions (e.g., PBS buffer) as well as high viscosity liquids (e.g., human blood) with a nanoliter-scale volume. Along with our acoustofluidic pump's low cost, programmability, and capacity to control small-volumes at high precision, it could be widely used for point-of-care diagnostics, precise drug delivery, and fundamental biomedical research.
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Affiliation(s)
- Zhuhao Wu
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology , Wuhan University , Wuhan 430072 , China.,Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
| | - Hongwei Cai
- Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
| | - Zheng Ao
- Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
| | - Asael Nunez
- Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
| | - Hongcheng Liu
- Department of Industrial and Systems Engineering , University of Florida , Gainesville , Florida 32611 , United States
| | - Maria Bondesson
- Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
| | - Shishang Guo
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology , Wuhan University , Wuhan 430072 , China
| | - Feng Guo
- Department of Intelligent Systems Engineering , Indiana University , Bloomington , Indiana 47405 , United States
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5
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Haehnel V, Khan FZ, Mutschke G, Cierpka C, Uhlemann M, Fritsch I. Combining magnetic forces for contactless manipulation of fluids in microelectrode-microfluidic systems. Sci Rep 2019; 9:5103. [PMID: 30911104 PMCID: PMC6433926 DOI: 10.1038/s41598-019-41284-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 03/01/2019] [Indexed: 11/09/2022] Open
Abstract
A novel method to drive and manipulate fluid in a contactless way in a microelectrode-microfluidic system is demonstrated by combining the Lorentz and magnetic field gradient forces. The method is based on the redox-reaction [Fe(CN)6]3-/[Fe(CN)6]4- performed in a magnetic field oriented perpendicular to the ionic current that crosses the gap between two arrays of oppositely polarized microelectrodes, generating a magnetohydrodynamic flow. Additionally, a movable magnetized CoFe micro-strip is placed at different positions beneath the gap. In this region, the magnetic flux density is changed locally and a strong magnetic field gradient is formed. The redox-reaction changes the magnetic susceptibility of the electrolyte near the electrodes, and the resulting magnetic field gradient exerts a force on the fluid, which leads to a deflection of the Lorentz force-driven main flow. Particle Image Velocity measurements and numerical simulations demonstrate that by combining the two magnetic forces, the flow is not only redirected, but also a local change of concentration of paramagnetic species is realized.
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Affiliation(s)
- Veronika Haehnel
- Institute for Complex Materials, IFW Dresden, Helmholtzstr. 20, D-01069, Dresden, Germany
| | - Foysal Z Khan
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Gerd Mutschke
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, D-01328, Dresden, Germany
| | - Christian Cierpka
- Institute of Thermodynamics and Fluid Mechanics,Technische Universität Ilmenau, D-98684, Ilmenau, Germany
| | - Margitta Uhlemann
- Institute for Complex Materials, IFW Dresden, Helmholtzstr. 20, D-01069, Dresden, Germany.
| | - Ingrid Fritsch
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA
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6
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Lee HB, Inoue S, Kim JH, Jeong M, Chung JH. Electrokinetic Behavior of Heat-Treated Mycobacterium Bacillus Calmette-Guérin Cells. J Med Device 2018. [DOI: 10.1115/1.4040677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Dielectrophoresis (DEP) can be an effective tool to show the physiological change of bacterial cells. The behavior of bacterial cells under an electric field is complicated due to the combined effects of electrokinetic phenomena. This paper presents the study of the electrokinetic behavior of heat-treated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) cells for a cell counting method. Through numerical and experimental study, heat-treated BCG cells are compared with control BCG cells. At various frequencies with the medium conductivity of 0.07 S/m, the equilibrium positions of both control- and heat-treated cells are analyzed in the combined fields of DEP and AC electroosmosis (ACEO). As DEP changes from negative to positive in electroosmotic flow, the equilibrium position of cells is bifurcated from the upper center between two electrodes onto the edges of both electrodes. It was found that the cells floating on electrodes should not be counted as attracted cells because the floating was resulted from the combined effect of the negative DEP and ACEO. According to the analysis, an optimum frequency is proposed to differentiate control cells from heat-treated cells using a cell counting method. The presented study will offer physical insight for the cell counting to differentiate live and dead Mycobacterium bovis BCG cells treated with heat and drugs.
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Affiliation(s)
- Hyun-Boo Lee
- Department of Mechanical Engineering, University of Washington, P.O. Box 352600, Seattle, WA 98195 e-mail:
| | - Shinnosuke Inoue
- Department of Mechanical Engineering, University of Washington, P.O. Box 352600, Seattle, WA 98195 e-mail:
| | - Jong-Hoon Kim
- School of Engineering and Computer Science, Washington State University, Vancouver, WA 98686 e-mail:
| | - Minjoong Jeong
- National Supercomputing Center, Korea Institute of Science and Technology Information, Daejeon 34141, South Korea e-mail:
| | - Jae-Hyun Chung
- Department of Mechanical Engineering, University of Washington, P.O. Box 352600, Seattle, WA 98195 e-mail:
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7
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Wang X, Zhao D, Phan DTT, Liu J, Chen X, Yang B, Hughes CCW, Zhang W, Lee AP. A hydrostatic pressure-driven passive micropump enhanced with siphon-based autofill function. LAB ON A CHIP 2018; 18:2167-2177. [PMID: 29931005 PMCID: PMC6057814 DOI: 10.1039/c8lc00236c] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Autonomous and self-powered micropumps are in critical demand for versatile cell- and tissue-based applications as well as for low-cost point-of-care testing (POCT) in microfluidics fields. The hydrostatic pressure-driven passive micropumps are simple and widely used, but they cannot maintain steady and continuous flow for long periods of time. Here, we propose a hydrostatic pressure-driven passive micropump enhanced with siphon-based autofill function, which can realize the autonomous and continuous perfusion with well-controlled steady flow over an extended time without electric power consumption. The characterization results reveal that both the cycle number in one refilling loop and the siphon diameter will affect the refilling time. Furthermore, this micropump also enables multiplexed medium delivery under either the same or different flow conditions with high flexibility. The system was validated using an in vitro vasculogenesis model over the course of several days. Most importantly, the device can consistently provide steady medium perfusion for up to 5 days at a predefined hydrostatic pressure drop without the need for supplemental medium changes. We believe that this hydrostatic pressure-driven passive micropump will become a critical module for a broad range of sophisticated microfluidic operations and applications.
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Affiliation(s)
- Xiaolin Wang
- Department of Micro/Nano Electronics, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
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8
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Zhao W, Liu X, Yang F, Wang K, Bai J, Qiao R, Wang G. Study of Oscillating Electroosmotic Flows with High Temporal and Spatial Resolution. Anal Chem 2018; 90:1652-1659. [PMID: 29256244 DOI: 10.1021/acs.analchem.7b02985] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Near-wall velocity of oscillating electroosmotic flow (OEOF) driven by an AC electric field has been investigated using a laser-induced fluorescence photobleaching anemometer (LIFPA). For the first time, an up to 3 kHz velocity response of OEOF has been successfully measured experimentally, even though the oscillating velocity is as low as 600 nm/s. It is found that the oscillating velocity decays with the forcing frequency ff as ff-0.66. In the investigated range of electric field intensity (EA), below 1 kHz, the linear relation between oscillating velocity and EA is also observed. Because the oscillating velocity at high frequency is very small, the contribution of noise to velocity measurement is significant, and it is discussed in this manuscript. The investigation reveals the instantaneous response of OEOF to the temporal change of electric fields, which exists in almost all AC electrokinetic flows. Furthermore, the experimental observations are important for designing OEOF-based micro/nanofluidics systems.
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Affiliation(s)
- Wei Zhao
- Institute of Photonics and Photon-technology, International Scientific and Technological Cooperation Base of Photoelectric Technology and Functional Materials and Application, Northwest University , 229 North Taibai Road, Xi'an 710069, People's Republic of China.,Department of Mechanical Engineering & Biomedical Engineering Program, University of South Carolina , Columbia, South Carolina 29208, United States
| | - Xin Liu
- Department of Mechanical Engineering & Biomedical Engineering Program, University of South Carolina , Columbia, South Carolina 29208, United States
| | - Fang Yang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, Jilin University , Changchun 130012, People's Republic of China
| | - Kaige Wang
- Institute of Photonics and Photon-technology, International Scientific and Technological Cooperation Base of Photoelectric Technology and Functional Materials and Application, Northwest University , 229 North Taibai Road, Xi'an 710069, People's Republic of China
| | - Jintao Bai
- Institute of Photonics and Photon-technology, International Scientific and Technological Cooperation Base of Photoelectric Technology and Functional Materials and Application, Northwest University , 229 North Taibai Road, Xi'an 710069, People's Republic of China
| | - Rui Qiao
- Department of Mechanical Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Guiren Wang
- Department of Mechanical Engineering & Biomedical Engineering Program, University of South Carolina , Columbia, South Carolina 29208, United States
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10
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Wang J, Wei MT, Ou-Yang HD. Low-frequency dielectrophoretic response of a single particle in aqueous suspensions. BIOMICROFLUIDICS 2016; 10:014108. [PMID: 26858820 PMCID: PMC4714981 DOI: 10.1063/1.4940037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 01/04/2016] [Indexed: 06/05/2023]
Abstract
We use optical tweezers-based dielectrophoresis (DEP) force spectroscopy to investigate the roles of the electrical double layer in the AC dielectric response of an individual colloidal particle in an aqueous medium. Specifically, we measure the DEP crossover frequency as a function of particles size, medium viscosity, and temperature. Experimental results were compared to low frequency relaxation mechanisms predicted by Schwarz, demonstrating the dielectrophoretic responses in the frequency range between 10 kHz and 1 MHz were dominated by counterion diffusion within the electric double layer.
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Affiliation(s)
- Jingyu Wang
- Department of Physics, Lehigh University , Bethlehem, Pennsylvania 18015, USA
| | - Ming-Tzo Wei
- Bioengineering Program, Lehigh University , Bethlehem, Pennsylvania 18015, USA
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11
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Sritharan D, Chen AS, Aluthgama P, Naved B, Smela E. Bubble-free electrokinetic flow with propylene carbonate. Electrophoresis 2015; 36:2622-9. [DOI: 10.1002/elps.201400443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 05/27/2015] [Accepted: 07/05/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Deepa Sritharan
- Department of Mechanical Engineering; University of Maryland; College Park MD USA
| | - Abraham Simpson Chen
- Department of Mechanical Engineering; University of Maryland; College Park MD USA
| | - Prabhath Aluthgama
- Department of Mechanical Engineering; University of Maryland; College Park MD USA
| | - Bilal Naved
- Department of Bioengineering; University of Maryland; College Park MD USA
| | - Elisabeth Smela
- Department of Mechanical Engineering; University of Maryland; College Park MD USA
- Institute for Systems Research; University of Maryland; College Park MD USA
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12
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Liu C, Kim K, Fan DL. Location deterministic biosensing from quantum-dot-nanowire assemblies. APPLIED PHYSICS LETTERS 2014; 105:083123. [PMID: 25316926 PMCID: PMC4187253 DOI: 10.1063/1.4893878] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 08/12/2014] [Indexed: 06/04/2023]
Abstract
Semiconductor quantum dots (QDs) with high fluorescent brightness, stability, and tunable sizes, have received considerable interest for imaging, sensing, and delivery of biomolecules. In this research, we demonstrate location deterministic biochemical detection from arrays of QD-nanowire hybrid assemblies. QDs with diameters less than 10 nm are manipulated and precisely positioned on the tips of the assembled Gold (Au) nanowires. The manipulation mechanisms are quantitatively understood as the synergetic effects of dielectrophoretic (DEP) and alternating current electroosmosis (ACEO) due to AC electric fields. The QD-nanowire hybrid sensors operate uniquely by concentrating bioanalytes to QDs on the tips of nanowires before detection, offering much enhanced efficiency and sensitivity, in addition to the position-predictable rationality. This research could result in advances in QD-based biomedical detection and inspires an innovative approach for fabricating various QD-based nanodevices.
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Affiliation(s)
- Chao Liu
- Materials Science and Engineering Program, Texas Materials Institute, University of Texas at Austin , Austin, Texas 78712, USA
| | - Kwanoh Kim
- Department of Mechanical Engineering, University of Texas at Austin , Austin, Texas 78712, USA
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Abstract
A room temperature liquid metal based electroosmotic flow (EOF) pump has been proposed in this work. This low-cost EOF pump is convenient for both fabrication and integration. It utilizes polydimethylsiloxane (PDMS) microchannels filled with the liquid-metal as non-contact pump electrodes. The electrode channels are fabricated symmetrically to both sides of the pumping channel, having no contact with the pumping channel. To test the pumping performance of the EOF pump, the mean flow velocities of the fluid (DI water) in the EOF pumps were experimentally measured by tracing the fluorescent microparticles in the flow. To provide guidance for designing a low voltage EOF pump, parametric studies on dimensions of the electrode and pumping channels were performed in this work. According to the experimental results, the pumping speed can reach 5.93 μm s(-1) at a driving voltage of only 1.6 V, when the gap between the electrode and the pumping channel is 20 μm. Injecting a room temperature liquid metal into microchannels can provide a simple, rapid, low-cost but accurately self-aligned way to fabricate microelectrodes for EOF pumps, which is a promising method to achieve the miniaturization and integration of the EOF pump in microfluidic systems. The non-contact liquid electrodes have no influence on the fluid in the pumping channel when pumping, reducing Joule heat generation and preventing gas bubble formation at the surface of electrodes. The pump has great potential to drive a wide range of fluids, such as drug reagents, cell suspensions and biological macromolecule solutions.
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Affiliation(s)
- Meng Gao
- Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, PR China.
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14
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Wang J, Wei MT, Cohen JA, Ou-Yang HD. Mapping alternating current electroosmotic flow at the dielectrophoresis crossover frequency of a colloidal probe. Electrophoresis 2014; 34:1915-21. [PMID: 23616351 DOI: 10.1002/elps.201200614] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 03/23/2013] [Accepted: 03/25/2013] [Indexed: 11/08/2022]
Abstract
AC electroosmotic (ACEO) flow above the gap between coplanar electrodes is mapped by the measurement of Stokes forces on an optically trapped polystyrene colloidal particle. E²-dependent forces on the probe particle are selected by amplitude modulation (AM) of the ACEO electric field (E) and lock-in detection at twice the AM frequency. E²-dependent DEP of the probe is eliminated by driving the ACEO at the probe's DEP crossover frequency. The location-independent DEP crossover frequency is determined, in a separate experiment, as the limiting frequency of zero horizontal force as the probe is moved toward the midpoint between the electrodes. The ACEO velocity field, uncoupled from probe DEP effects, was mapped in the region 1-9 μm above a 28 μm gap between the electrodes. By use of variously sized probes, each at its DEP crossover frequency, the frequency dependence of the ACEO flow was determined at a point 3 μm above the electrode gap and 4 μm from an electrode tip. At this location the ACEO flow was maximal at ∼117 kHz for a low salt solution. This optical trapping method, by eliminating DEP forces on the probe, provides unambiguous mapping of the ACEO velocity field.
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Affiliation(s)
- Jingyu Wang
- Department of Physics, Lehigh University, Bethlehem, PA, USA
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15
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Horiuchi T, Hayashi K, Seyama M, Inoue S, Tamechika E. Cooperative suction by vertical capillary array pump for controlling flow profiles of microfluidic sensor chips. SENSORS (BASEL, SWITZERLAND) 2012; 12:14053-67. [PMID: 23202035 PMCID: PMC3545606 DOI: 10.3390/s121014053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 09/27/2012] [Accepted: 10/10/2012] [Indexed: 11/29/2022]
Abstract
A passive pump consisting of integrated vertical capillaries has been developed for a microfluidic chip as an useful component with an excellent flow volume and flow rate. A fluidic chip built into a passive pump was used by connecting the bottoms of all the capillaries to a top surface consisting of a thin layer channel in the microfluidic chip where the thin layer channel depth was smaller than the capillary radius. As a result the vertical capillaries drew fluid cooperatively rather than independently, thus exerting the maximum suction efficiency at every instance. This meant that a flow rate was realized that exhibited little variation and without any external power or operation. A microfluidic chip built into this passive pump had the ability to achieve a quasi-steady rather than a rapidly decreasing flow rate, which is a universal flow characteristic in an ordinary capillary.
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Affiliation(s)
- Tsutomu Horiuchi
- NTT Microsystem Integration Laboratories, Nippon Telegraph and Telephone Corporation (NTT), Morinosato-Wakamiya, Atsugi-shi, Kanagawa 2430198, Japan; E-Mails: (M.S.); (S.I.); (E.T.)
| | - Katsuyoshi Hayashi
- NTT Microsystem Integration Laboratories, Nippon Telegraph and Telephone Corporation (NTT), Morinosato-Wakamiya, Atsugi-shi, Kanagawa 2430198, Japan; E-Mails: (M.S.); (S.I.); (E.T.)
| | - Michiko Seyama
- NTT Microsystem Integration Laboratories, Nippon Telegraph and Telephone Corporation (NTT), Morinosato-Wakamiya, Atsugi-shi, Kanagawa 2430198, Japan; E-Mails: (M.S.); (S.I.); (E.T.)
| | - Suzuyo Inoue
- NTT Microsystem Integration Laboratories, Nippon Telegraph and Telephone Corporation (NTT), Morinosato-Wakamiya, Atsugi-shi, Kanagawa 2430198, Japan; E-Mails: (M.S.); (S.I.); (E.T.)
| | - Emi Tamechika
- NTT Microsystem Integration Laboratories, Nippon Telegraph and Telephone Corporation (NTT), Morinosato-Wakamiya, Atsugi-shi, Kanagawa 2430198, Japan; E-Mails: (M.S.); (S.I.); (E.T.)
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Sasaki N, Takemura A, Sato K. Alternating current cloud point extraction on a microchip: a comprehensive study. Electrophoresis 2012; 33:3159-65. [PMID: 23027025 DOI: 10.1002/elps.201200229] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 06/15/2012] [Accepted: 06/20/2012] [Indexed: 12/13/2022]
Abstract
We present a comprehensive study of alternating current cloud point extraction (ACPE) on a microchip. ACPE is an extraction technique for preconcentration of membrane-associated biomolecules. To characterize and optimize ACPE, we carried out ACPE experiments under various experimental conditions including amplitude and frequency of applied voltages, flow velocity, and concentration of surfactant, analyte, and salt. We found that ACPE has an amplitude threshold (15 V(p-p)), above which the extraction was more efficient. The dependence of the extraction on frequency (>5 MHz) was insignificant. Efficient extraction was achieved when the velocity of the test solution was 0.10∼0.67 mm s⁻¹ and the concentration of surfactant was 0.10∼1.0%. In contrast, the extraction was independent of the concentration of analytes (0.20∼20 μmol dm⁻³). The technique was applicable to solutions with a salt concentration of 0.050∼0.15 mol dm⁻³ under temperature control of the devices. Solution temperature in ACPE was also studied. These results provide guidelines for use of the ACPE technique in microfluidic chemical and biochemical analyses.
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Affiliation(s)
- Naoki Sasaki
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo, Tokyo, Japan.
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17
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SASAKI N. Recent Applications of AC Electrokinetics in Biomolecular Analysis on Microfluidic Devices. ANAL SCI 2012; 28:3-8. [DOI: 10.2116/analsci.28.3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Naoki SASAKI
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women’s University
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18
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Melvin EM, Moore BR, Gilchrist KH, Grego S, Velev OD. On-chip collection of particles and cells by AC electroosmotic pumping and dielectrophoresis using asymmetric microelectrodes. BIOMICROFLUIDICS 2011; 5:34113-3411317. [PMID: 22662040 PMCID: PMC3364828 DOI: 10.1063/1.3620419] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Accepted: 07/12/2011] [Indexed: 05/10/2023]
Abstract
The recent development of microfluidic "lab on a chip" devices requiring sample sizes <100 μL has given rise to the need to concentrate dilute samples and trap analytes, especially for surface-based detection techniques. We demonstrate a particle collection device capable of concentrating micron-sized particles in a predetermined area by combining AC electroosmosis (ACEO) and dielectrophoresis (DEP). The planar asymmetric electrode pattern uses ACEO pumping to induce equal, quadrilateral flow directed towards a stagnant region in the center of the device. A number of system parameters affecting particle collection efficiency were investigated including electrode and gap width, chamber height, applied potential and frequency, and number of repeating electrode pairs and electrode geometry. The robustness of the on-chip collection design was evaluated against varying electrolyte concentrations, particle types, and particle sizes. These devices are amenable to integration with a variety of detection techniques such as optical evanescent waveguide sensing.
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19
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20
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Yeh HC, Yang RJ, Luo WJ. Analysis of traveling-wave electro-osmotic pumping with double-sided electrode arrays. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:056326. [PMID: 21728666 DOI: 10.1103/physreve.83.056326] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Indexed: 05/31/2023]
Abstract
In this paper, a series of numerical simulations was performed to investigate the pumping performance of electro-osmotic micropumps containing electrode arrays patterned on the upper and lower sides of a microchannel. The simulations have been analyzed with a linear electro-osmotic model based upon the Debye-Hückel theory of the double layer. The potential drop across the diffuse layer is assumed to be less than 25 mV (k(B)T/e), and there is a linear response between the surface charge and the voltage drop across the double layer. The double layer is not resolved but is lumped into effective parameters that are imported from the Debye-Hückel and Stern layers. We examined the effects of the relative positioning of the electrodes in the opposing arrays (i.e., symmetrical or staggered), and the phase lag and the angular frequency of the alternating current (ac) signals applied to the electrodes within the two arrays. A critical height of the microchannel was observed, below which the interactions of the applied electrical potentials on the walls became significant. The optimum pumping effect was obtained when the electrode arrays were symmetrical to one another around the centerline of the channel and were activated by ac potentials with a 0° phase shift. The corresponding angular frequency of the maximum pumping velocity for different phase shifts of the applied ac signals was also determined. Overall, the simulation results presented in this paper provide a useful insight into the optimal design parameters and operating conditions for micropumps containing two arrays of microelectrodes on the microchannel walls.
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Affiliation(s)
- Hung-Chun Yeh
- Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan
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21
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22
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So JH, Dickey MD. Inherently aligned microfluidic electrodes composed of liquid metal. LAB ON A CHIP 2011; 11:905-11. [PMID: 21264405 DOI: 10.1039/c0lc00501k] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This paper describes the fabrication and characterization of microelectrodes that are inherently aligned with microfluidic channels and in direct contact with the fluid in the channels. Injecting low melting point alloys, such as eutectic gallium indium (EGaIn), into microchannels at room temperature (or just above room temperature) offers a simple way to fabricate microelectrodes. The channels that define the shape and position of the microelectrodes are fabricated simultaneously with other microfluidic channels (i.e., those used to manipulate fluids) in a single step; consequently, all of the components are inherently aligned. In contrast, conventional techniques require multiple fabrication steps and registration (i.e., alignment of the electrodes with the microfluidic channels), which are technically challenging. The distinguishing characteristic of this work is that the electrodes are in direct contact with the fluid in the microfluidic channel, which is useful for a number of applications such as electrophoresis. Periodic posts between the microelectrodes and the microfluidic channel prevent the liquid metal from entering the microfluidic channel during injection. A thin oxide skin that forms rapidly and spontaneously on the surface of the metal stabilizes mechanically the otherwise low viscosity, high surface tension fluid within the channel. Moreover, the injected electrodes vertically span the sidewalls of the channel, which allows for the application of uniform electric field lines throughout the height of the channel and perpendicular to the direction of flow. The electrodes are mechanically stable over operating conditions commonly used in microfluidic applications; the mechanical stability depends on the magnitude of the applied bias, the nature of the bias (DC vs. AC), and the conductivity of the solutions in the microfluidic channel. Electrodes formed using alloys with melting points above room temperature ensure mechanical stability over all of the conditions explored. As a demonstration of their utility, the fluidic electrodes are used for electrohydrodynamic mixing, which requires extremely high electric fields (~10(5) V m(-1)).
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Affiliation(s)
- Ju-Hee So
- Department of Chemical and Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, NC 27695, USA
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23
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Mishchuk NA, Heldal T, Volden T, Auerswald J, Knapp H. Micropump based on electroosmosis of the second kind. Electrophoresis 2010; 30:3499-506. [PMID: 19784952 DOI: 10.1002/elps.200900271] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A microfluidic pump based on electroosmosis of the second kind was designed and fabricated. Experimental results using DC and AC voltages showed a close to second-order relationship between flow and voltage, in good agreement with theory. The experimental flow rates were considerably lower than the predicted maximum for the micropumps, which can be attributed to the hydrodynamic resistance of the channel network. This also indicates that higher flow velocities are obtainable for modified pump designs.
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Affiliation(s)
- Nataliya A Mishchuk
- Institute of Colloid and Water Chemistry of National Academy of Sciences of Ukraine, Kiev Ukraine.
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24
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Towards an understanding of induced-charge electrokinetics at large applied voltages in concentrated solutions. Adv Colloid Interface Sci 2009; 152:48-88. [PMID: 19879552 DOI: 10.1016/j.cis.2009.10.001] [Citation(s) in RCA: 427] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 09/29/2009] [Accepted: 10/01/2009] [Indexed: 11/22/2022]
Abstract
The venerable theory of electrokinetic phenomena rests on the hypothesis of a dilute solution of point-like ions in quasi-equilibrium with a weakly charged surface, whose potential relative to the bulk is of order the thermal voltage (kT/e approximately 25 mV at room temperature). In nonlinear electrokinetic phenomena, such as AC or induced-charge electro-osmosis (ACEO, ICEO) and induced-charge electrophoresis (ICEP), several V approximately 100 kT/e are applied to polarizable surfaces in microscopic geometries, and the resulting electric fields and induced surface charges are large enough to violate the assumptions of the classical theory. In this article, we review the experimental and theoretical literatures, highlight discrepancies between theory and experiment, introduce possible modifications of the theory, and analyze their consequences. We argue that, in response to a large applied voltage, the "compact layer" and "shear plane" effectively advance into the liquid, due to the crowding of counterions. Using simple continuum models, we predict two general trends at large voltages: (i) ionic crowding against a blocking surface expands the diffuse double layer and thus decreases its differential capacitance, and (ii) a charge-induced viscosity increase near the surface reduces the electro-osmotic mobility; each trend is enhanced by dielectric saturation. The first effect is able to predict high-frequency flow reversal in ACEO pumps, while the second may explain the decay of ICEO flow with increasing salt concentration. Through several colloidal examples, such as ICEP of an uncharged metal sphere in an asymmetric electrolyte, we show that nonlinear electrokinetic phenomena are generally ion-specific. Similar theoretical issues arise in nanofluidics (due to confinement) and ionic liquids (due to the lack of solvent), so the paper concludes with a general framework of modified electrokinetic equations for finite-sized ions.
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Abstract
Dispersion or spreading of analyte bands is a barrier to achieving high resolution in microfluidic separations. The role of dispersion in separations is reviewed with emphasis on metrics, sources and common principles of analysis. Three sources of dispersion (a) inhomogeneous flow fields, (b) solute wall interactions and (c) force fields normal to channel walls are studied in detail. Microfluidic and nanofluidic applications to capillary electrophoresis, chromatography and field-flow fractionation, that are subject to one or more of these three physical processes under standard, unintentional or novel operating conditions, are discussed.
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Affiliation(s)
- Subhra Datta
- 201, W 19th Avenue, Mechanical Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Sandip Ghosal
- 2145 Sheridan Road, Mechanical Engineering, Northwestern University, Evanston, IL 60208-3111, USA
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26
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Gregersen MM, Andersen MB, Soni G, Meinhart C, Bruus H. Numerical analysis of finite Debye-length effects in induced-charge electro-osmosis. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:066316. [PMID: 19658603 DOI: 10.1103/physreve.79.066316] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Indexed: 05/28/2023]
Abstract
For a microchamber filled with a binary electrolyte and containing a flat unbiased center electrode at one wall, we employ three numerical models to study the strength of the resulting induced-charge electro-osmotic (ICEO) flow rolls: (i) a full nonlinear continuum model resolving the double layer, (ii) a linear slip-velocity model not resolving the double layer and without tangential charge transport inside this layer, and (iii) a nonlinear slip-velocity model extending the linear model by including the tangential charge transport inside the double layer. We show that, compared to the full model, the slip-velocity models significantly overestimate the ICEO flow. This provides a partial explanation of the quantitative discrepancy between observed and calculated ICEO velocities reported in the literature. The discrepancy increases significantly for increasing Debye length relative to the electrode size, i.e., for nanofluidic systems. However, even for electrode dimensions in the micrometer range, the discrepancies in velocity due to the finite Debye length can be more than 10% for an electrode of zero height and more than 100% for electrode heights comparable to the Debye length.
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Affiliation(s)
- Misha Marie Gregersen
- Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, DK-2800 Kongens Lyngby, Denmark
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27
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Ng WY, Lam YC, Rodríguez I. Experimental verification of Faradaic charging in ac electrokinetics. BIOMICROFLUIDICS 2009; 3:22405. [PMID: 19693340 PMCID: PMC2717573 DOI: 10.1063/1.3120273] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Accepted: 03/21/2009] [Indexed: 05/06/2023]
Abstract
This paper investigates the phenomenon of Faradaic charging in ac electrokinetics. Faradaic reactions were suggested as a key effect responsible for the reversal of pumping direction in ac micropumps. However, this hypothesis has yet to be proven convincingly and directly. Here we present an ion detection strategy to determine the production of ions through Faradaic hydrolytic reactions originating from direct application of voltage to electrolytic solutions during ac electrokinetics. Experiments were performed with symmetrical planar electrodes aligned along a microfluidic channel. Fluorescein, a pH-dependent dye, was employed as the pH indicator for the detection of ion production. Images were captured for analysis at various voltage levels. From analyzing the fluorescence intensity and its distribution, it can be concluded that the production of ions from hydrolytic reactions takes place and increases with the ac voltage. The coefficient of deviation indicates a significant enhancement at ac voltage above 11 V(pp). Lastly, we demonstrate a strategy using dc-biased ac electrokinetics to achieve controllability in direction and magnitude of the net fluid flow in pumping application.
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28
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Ng WY, Goh S, Lam YC, Yang C, Rodríguez I. DC-biased AC-electroosmotic and AC-electrothermal flow mixing in microchannels. LAB ON A CHIP 2009; 9:802-9. [PMID: 19255662 DOI: 10.1039/b813639d] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This paper presents a novel approach of mixing two laminar flowing streams in microchannels. The mixer consists of a pair of electrodes disposed along a fluidic channel. By energizing the electrodes with a DC-biased (2.5 V) AC voltage (20 Vpp), an electrokinetic flow is induced with a flow profile perpendicular to that of the incoming laminar streams of liquids to be mixed. As a result, the flow lines of the incoming streams and the induced flow are forced to crossover and very efficient stirring and mixing at short mixing length can be achieved. The mixer can be operated from the AC-electroosmotic (ACEO) (sigma=1 mS/m, f=100 kHz) to the AC-electrothermal (ACET) (sigma=500 mS/m, f=500 kHz) flow regimes. The mixing efficiency in the ACEO regime was 92%, with a mixing length of 600 microm (Q=2 microL/min), an estimated mixing time of 69 ms and an induced ACEO flow velocity of approximately 725 microm/s. The mixing efficiency in the ACET regime was 65% for a mixing length of approximately 1200 microm. The mixer is efficient and suitable for mixing reagents in a fluid media from low to high conductivity as required in diverse microfluidic applications.
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Affiliation(s)
- Wee Yang Ng
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 3 Research Link, Singapore 117602
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29
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Wang X, Cheng C, Wang S, Liu S. Electroosmotic pumps and their applications in microfluidic systems. MICROFLUIDICS AND NANOFLUIDICS 2009; 6:145. [PMID: 20126306 PMCID: PMC2756694 DOI: 10.1007/s10404-008-0399-9] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Electroosmotic pumping is receiving increasing attention in recent years owing to the rapid development in micro total analytical systems. Compared with other micropumps, electroosmotic pumps (EOPs) offer a number of advantages such as creation of constant pulse-free flows and elimination of moving parts. The flow rates and pumping pressures of EOPs matches well with micro analysis systems. The common materials and fabrication technologies make it readily integrateable with lab-on-a-chip devices. This paper reviews the recent progress on EOP fabrications and applications in order to promote the awareness of EOPs to researchers interested in using micro- and nano-fluidic devices. The pros and cons of EOPs are also discussed, which helps these researchers in designing and constructing their micro platforms.
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Affiliation(s)
- Xiayan Wang
- Department of Chemistry and Biochemistry, The University of Oklahoma, Norman, OK 73019, USA
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30
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Rapp BE, Carneiro L, Länge K, Rapp M. An indirect microfluidic flow injection analysis (FIA) system allowing diffusion free pumping of liquids by using tetradecane as intermediary liquid. LAB ON A CHIP 2009; 9:354-356. [PMID: 19107296 DOI: 10.1039/b815690e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We suggest an indirect microfluidic flow injection analysis (FIA) system which uses tetradecane (C14H30) as intermediary liquid allowing the diffusion free handling of liquids in a fluidic system which is suitable for single use applications as required, e.g., biomedical applications.
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Affiliation(s)
- Bastian Ernst Rapp
- Institute for Microstructure Technology (IMT), Forschungszentrum Karlsruhe, Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
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31
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Girardo S, Cecchini M, Beltram F, Cingolani R, Pisignano D. Polydimethylsiloxane-LiNbO3 surface acoustic wave micropump devices for fluid control into microchannels. LAB ON A CHIP 2008; 8:1557-63. [PMID: 18818813 DOI: 10.1039/b803967d] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
This paper presents prototypical microfluidic devices made by hybrid microchannels based on piezoelectric LiNbO(3) and polydimethylsiloxane. This system enables withdrawing micropumping by acoustic radiation in microchannels. The withdrawing configuration, integrated on chip, is here quantitatively investigated for the first time, and found to be related to the formation and coalescence dynamics of droplets within the microchannel, primed by surface acoustic waves. The growth dynamics of droplets is governed by the water diffusion on LiNbO(3), determining the advancement of the fluid front. Observed velocities are up to 2.6 mm s(-1) for 30 dBm signals applied to the interdigital transducer, corresponding to tens of nl s(-1), and the micropumping dynamics is described by a model taking into account an acoustic power exponentially decaying upon travelling along the microchannel. This straighforward and flexible micropumping approach is particularly promising for the withdrawing of liquids in lab-on-chip devices performing cycling transport of fluids and biochemical reactions.
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Affiliation(s)
- Salvatore Girardo
- National Nanotechnology Laboratory of CNR-INFM, Università del Salento, Italy
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32
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Meng DD, Kim CJCJ. Micropumping of liquid by directional growth and selective venting of gas bubbles. LAB ON A CHIP 2008; 8:958-68. [PMID: 18497918 DOI: 10.1039/b719918j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
We introduce a new mechanism to pump liquid in microchannels based on the directional growth and displacement of gas bubbles in conjunction with the non-directional and selective removal of the bubbles. A majority of the existing bubble-driven micropumps employs boiling despite the unfavorable scaling of energy consumption for miniaturization because the vapor bubbles can be easily removed by condensation. Other gas generation methods are rarely suitable for micropumping applications because it is difficult to remove the gas bubbles promptly from a pump loop. In order to eradicate this limitation, the rapid removal of insoluble gas bubbles without liquid leakage is achieved with hydrophobic nanopores, allowing the use of virtually any kind of bubbles. In this paper, electrolysis and gas injection are demonstrated as two distinctively different gas sources. The proposed mechanism is first proved by circulating water in a looped microchannel. Using H(2) and O(2) gas bubbles continuously generated by electrolysis, a prototype device with a looped channel shows a volumetric flow rate of 4.5-13.5 nL s(-1) with a direct current (DC) power input of 2-85 mW. A similar device with an open-ended microchannel gives a maximum flow rate of approximately 65 nL s(-1) and a maximum pressure head of approximately 195 Pa with 14 mW input. The electrolytic-bubble-driven micropump operates with a 10-100 times higher power efficiency than its thermal-bubble-driven counterparts and exhibits better controllability. The pumping mechanism is then implemented by injecting nitrogen gas bubbles to demonstrate the flexibility of bubble sources, which would allow one to choose them for specific needs (e.g., energy efficiency, thermal sensitivity, biocompatibility, and adjustable flow rate), making the proposed mechanism attractive for many applications including micro total analysis systems (microTAS) and micro fuel cells.
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Affiliation(s)
- Dennis Desheng Meng
- Mechanical and Aerospace Engineering Department, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095-1597, USA.
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33
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Abstract
A novel ac electrokinetic microfluidic driver based on alternating current electro-osmosis flow induced by asymmetrically capacitance/chemistry-modulated microelectrode arrays has been successfully developed and demonstrated. Asymmetric capacitance modulation (ACM) is made of comb electrode arrays and parts of individual electrode surfaces are modulated/deposited with a SiO(2) dielectric layer. This proposed design can be utilized to shift the optimal operation frequency of maximum velocity to a higher frequency to minimize electrolytic bubble generation and enhance micropumping performance. The pumping velocity, described in this paper, is measured via the tracing of microbeads and is a function of applied potential, signal frequency, buffer concentration, and dielectric layer thickness. A maximum pumping velocity up to 290 microm s(-1) in 5 mM buffer solution with the applied potential of 10 Vpp is observed in our prototype device, and the estimated maximum flow rate is up to 26.1 microl h(-1). This is the first successful demonstration regarding bubble-free ac electrokinetic micropumping via such asymmetrically capacitance-modulated electrode arrays. Design, simulation, microfabrication, experimental result, and theoretical model are described in this paper to characterize and exhibit the performance of the proposed novel bubble-free ac electrokinetic microfluidic driver.
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Affiliation(s)
- Ching-Te Kuo
- Department of Power Mechanical Engineering, National Tsing-Hua University, Hsinchu, Taiwan 30043, Republic of China
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34
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Chang ST, Beaumont E, Petsev DN, Velev OD. Remotely powered distributed microfluidic pumps and mixers based on miniature diodes. LAB ON A CHIP 2008; 8:117-24. [PMID: 18094769 DOI: 10.1039/b712108c] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We demonstrate new principles of microfluidic pumping and mixing by electronic components integrated into a microfluidic chip. The miniature diodes embedded into the microchannel walls rectify the voltage induced between their electrodes from an external alternating electric field. The resulting electroosmotic flows, developed in the vicinity of the diode surfaces, were utilized for pumping or mixing of the fluid in the microfluidic channel. The flow velocity of liquid pumped by the diodes facing in the same direction linearly increased with the magnitude of the applied voltage and the pumping direction could be controlled by the pH of the solutions. The transverse flow driven by the localized electroosmotic flux between diodes oriented oppositely on the microchannel was used in microfluidic mixers. The experimental results were interpreted by numerical simulations of the electrohydrodynamic flows. The techniques may be used in novel actively controlled microfluidic-electronic chips.
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Affiliation(s)
- Suk Tai Chang
- Department of Chemical & Biomolecular Engineering, North Carolina State University, 911 Partners Way, Raleigh, USA
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35
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Thwar PK, Linderman JJ, Burns MA. Electrodeless direct current dielectrophoresis using reconfigurable field-shaping oil barriers. Electrophoresis 2007; 28:4572-81. [DOI: 10.1002/elps.200700373] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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36
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Gregersen MM, Olesen LH, Brask A, Hansen MF, Bruus H. Flow reversal at low voltage and low frequency in a microfabricated ac electrokinetic pump. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:056305. [PMID: 18233754 DOI: 10.1103/physreve.76.056305] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Indexed: 05/07/2023]
Abstract
Microfluidic chips have been fabricated in Pyrex glass to study electrokinetic pumping generated by a low-voltage ac bias applied to an in-channel asymmetric metallic electrode array. A measurement procedure has been established and followed carefully resulting in a high degree of reproducibility of the measurements over several days. A large coverage fraction of the electrode array in the microfluidic channels has led to an increased sensitivity allowing for pumping measurements at low bias voltages. Depending on the ionic concentration a hitherto unobserved reversal of the pumping direction has been measured in a regime, where both the applied voltage and the frequency are low, V(rms)<1.5 V and f<20 kHz , compared to previously investigated parameter ranges. The impedance spectrum has been thoroughly measured and analyzed in terms of an equivalent circuit diagram to rule out trivial circuit explanations of our findings. Our observations agree qualitatively, but not quantitatively, with theoretical electrokinetic models published in the literature.
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Affiliation(s)
- Misha Marie Gregersen
- MIC-Department of Micro and Nanotechnology, Technical University of Denmark, DTU Building 345 East, DK-2800 Kongens Lyngby, Denmark
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37
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Yan D, Nguyen NT, Yang C, Huang X. Visualizing the transient electroosmotic flow and measuring the zeta potential of microchannels with a micro-PIV technique. J Chem Phys 2007; 124:021103. [PMID: 16422562 DOI: 10.1063/1.2162533] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have demonstrated a transient micro particle image velocimetry (micro-PIV) technique to measure the temporal development of electroosmotic flow in microchannels. Synchronization of different trigger signals for the laser, the CCD camera, and the high-voltage switch makes this measurement possible with a conventional micro-PIV setup. Using the transient micro-PIV technique, we have further proposed a method on the basis of inertial decoupling between the particle electrophoretic motion and the fluid electroosmotic flow to determine the electrophoretic component in the particle velocity and the zeta potential of the channel wall. It is shown that using the measured zeta potentials, the theoretical predictions agree well with the transient response of the electroosmotic velocities measured in this work.
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Affiliation(s)
- Deguang Yan
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
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38
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Chang ST, Paunov VN, Petsev DN, Velev OD. Remotely powered self-propelling particles and micropumps based on miniature diodes. NATURE MATERIALS 2007; 6:235-40. [PMID: 17293850 DOI: 10.1038/nmat1843] [Citation(s) in RCA: 178] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Accepted: 01/10/2007] [Indexed: 05/13/2023]
Abstract
Microsensors and micromachines that are capable of self-propulsion through fluids could revolutionize many aspects of technology. Few principles to propel such devices and supply them with energy are known. Here, we show that various types of miniature semiconductor diodes floating in water act as self-propelling particles when powered by an external alternating electric field. The millimetre-sized diodes rectify the voltage induced between their electrodes. The resulting particle-localized electro-osmotic flow propels them in the direction of either the cathode or the anode, depending on their surface charge. These rudimentary self-propelling devices can emit light or respond to light and could be controlled by internal logic. Diodes embedded in the walls of microfluidic channels provide locally distributed pumping or mixing functions powered by a global external field. The combined application of a.c. and d.c. fields in such devices allows decoupling of the velocity of the particles and the liquid and could be used for on-chip separations.
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Affiliation(s)
- Suk Tai Chang
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, USA
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Velev OD, Bhatt KH. On-chip micromanipulation and assembly of colloidal particles by electric fields. SOFT MATTER 2006; 2:738-750. [PMID: 32680214 DOI: 10.1039/b605052b] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We overview the ways in which electric fields can be used for on-chip manipulation and assembly of colloidal particles. Particles suspended in water readily respond to alternating (AC) or direct current (DC) electric fields. Charged particles in DC fields are moved towards oppositely charged electrodes by electrophoresis. Dielectrophoresis, particle mobility in AC fields, allows precise manipulation of particles through a range of parameters including field strength and frequency and electrode geometry. Simultaneously, DC or AC electrokinetics may drive liquid flows inside the experimental cells, which also leads to transport and redistribution of the suspended particles. Examples of dielectrophoretic manipulation and assembly of nanoparticles and microparticles by planar on-chip electrodes are presented. The structures assembled include conductive microwires from metallic nanoparticles and switchable two-dimensional crystals from polymer microspheres. We also discuss how dielectrophoresis and AC electrokinetics can be used in droplet-based microfluidic chips, biosensors, and devices for collection of particles from diluted suspensions.
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Affiliation(s)
- Orlin D Velev
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
| | - Ketan H Bhatt
- Department of Chemical & Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695, USA.
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Dittrich PS, Tachikawa K, Manz A. Micro Total Analysis Systems. Latest Advancements and Trends. Anal Chem 2006; 78:3887-908. [PMID: 16771530 DOI: 10.1021/ac0605602] [Citation(s) in RCA: 781] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Petra S Dittrich
- Institute for Analytical Sciences, Bunsen-Kirchhoff-Strasse 11, D-44139 Dortmund, Germany
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41
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Olesen LH, Bruus H, Ajdari A. ac electrokinetic micropumps: the effect of geometrical confinement, Faradaic current injection, and nonlinear surface capacitance. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:056313. [PMID: 16803043 DOI: 10.1103/physreve.73.056313] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2005] [Indexed: 05/10/2023]
Abstract
Recent experiments have demonstrated that ac electrokinetic micropumps permit integrable, local, and fast pumping (velocities approximately mm/s) with low driving voltage of a few volts only. However, they also displayed many quantitative and qualitative discrepancies with existing theories. We therefore extend the latter theories to account for three experimentally relevant effects: (i) vertical confinement of the pumping channel, (ii) Faradaic currents from electrochemical reactions at the electrodes, and (iii) nonlinear surface capacitance of the Debye layer. We report here that these effects indeed affect the pump performance in a way that we can rationalize by physical arguments.
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Affiliation(s)
- Laurits Højgaard Olesen
- MIC, Department of Micro and Nanotechnology, Technical University of Denmark, Kongens Lyngby
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Tay HK, Lee D, Xu G, Yang C. Design and Fabrication of a Flow Delivery Microdevice with Asymmetric Microelectrodes Pairs. ACTA ACUST UNITED AC 2006. [DOI: 10.1088/1742-6596/34/1/183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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43
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Sasaki N, Kitamori T, Kim HB. AC electroosmotic micromixer for chemical processing in a microchannel. LAB ON A CHIP 2006; 6:550-4. [PMID: 16572218 DOI: 10.1039/b515852d] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A rapid micromixer of fluids in a microchannel is presented. The mixer uses AC electroosmotic flow, which is induced by applying an AC voltage to a pair of coplanar meandering electrodes configured in parallel to the channel. To demonstrate performance of the mixer, dilution experiments were conducted using a dye solution in a channel of 120 microm width. Rapid mixing was observed for flow velocity up to 12 mm s(-1). The mixing time was 0.18 s, which was 20-fold faster than that of diffusional mixing without an additional mixing mechanism. Compared with the performance of reported micromixers, the present mixer worked with a shorter mixing length, particularly at low Peclet numbers (Pe < 2 x 10(3)).
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Affiliation(s)
- Naoki Sasaki
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo, Japan
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Yang X, Jenkins G, Franzke J, Manz A. Shear-driven pumping and Fourier transform detection for on chip circular chromatography applications. LAB ON A CHIP 2005; 5:764-71. [PMID: 15970970 DOI: 10.1039/b502121a] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A circular, shear-driven pumping system combined with Fourier Transform detection has been developed for the application of chip based cyclic chromatography. Using this system, it is possible to perform an injection of a sample plug into a circular micro-channel and then drive the sample through the channel, using shear flow induced by a rotation stage. High pumping rates at uniform speeds are attainable with this system with very little heat production. Typical pumping rates of up to 1.423 mm s(-1) +/- 2 microm s(-1) were used in experiments although much higher rates >14 mm s(-1) are also possible with this system. Fluorescence detection was used to detect a sample plug of Coumarin dyes, flowing around the channel. A coating of porous polymethacrylate was used to immobilise RP-HPLC beads onto the glass surface and was applied to the glass micro-channel by selective photopolymerisation. This coating acted as a stationary phase and differences in retention time were observed for an injection of Coumarin dyes for different methanol-water, mobile phase ratios. Full sample retention occurred for 30 : 70 (v/v) methanol-water whereas no retention occurred for 92 : 8 (v/v) methanol-water which can be expected for such a reverse phase, open tubular system. Fourier transform detection applied to the fully retained and non-retained cases showed frequency domain data from a single detection point corresponding to that which may be expected from shear flow theory.
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Affiliation(s)
- Xin Yang
- Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK.
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