Micro/Nano-Chip Electrokinetics, Volume III

A special issue of Micromachines (ISSN 2072-666X). This special issue belongs to the section "A:Physics".

Deadline for manuscript submissions: closed (31 October 2019) | Viewed by 70307

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Department of Mechanical Engineering, Clemson University, Clemson, SC 29634, USA
Interests: microfluidics; electrokinetics; magnetofluidics; viscoelasticity
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Guest Editor
Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, VA 23529, USA
Interests: micro/nanofluidics; non-Newtonian fluidics; transport phenomena in micro and nanoscales
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Micro/nanofluidic chips have found increasing applications in the analysis of chemical and biological samples over the past two decades. Electrokinetics has become the method of choice in these micro/nano-chips for transporting, manipulating and sensing ions, (bio)molecules, fluids and (bio)particles, etc., due to the high maneuverability, scalability, sensitivity, and integrability. The involved phenomena, which cover electroosmosis, electrophoresis, dielectrophoresis, electrohydrodynamics, electrothermal flow, diffusioosmosis, diffusiophoresis, streaming potential, current, etc., arise from either the inherent or the induced surface charge on the solid-liquid interface under DC and/or AC electric fields. To review the state-of-the-art of micro/nanochip electrokinetics, we welcome, in this Special Issue of Micromachines, all original research or review articles on the fundamentals and applications of the variety of electrokinetic phenomena in both microfluidic and nanofluidic devices.

Prof. Dr. Xiangchun Xuan
Prof. Dr. Shizhi Qian
Guest Editors

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Keywords

  • electrokinetics
  • micro/nanofluidics
  • electroosmosis
  • electrophoresis
  • diffusioosmosis
  • diffusiophoresis
  • streaming potential/current
  • dielectrophoresis
  • induced charge electrokinetics
  • electrical sensing

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Published Papers (16 papers)

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Editorial

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3 pages, 167 KiB  
Editorial
Editorial for the Special Issue on Micro/Nano-Chip Electrokinetics, Volume III
by Shizhi Qian and Xiangchun Xuan
Micromachines 2020, 11(5), 482; https://doi.org/10.3390/mi11050482 - 8 May 2020
Cited by 1 | Viewed by 1850
Abstract
With the support from contributors and the help from peer reviewers, the Special Issue on Micro/Nano-Chip Electrokinetics (Volume III) published fourteen regular research articles and one review article [...] Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)

Research

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11 pages, 2081 KiB  
Article
Characterization of the Dielectrophoretic Response of Different Candida Strains Using 3D Carbon Microelectrodes
by Monsur Islam, Devin Keck, Jordon Gilmore and Rodrigo Martinez-Duarte
Micromachines 2020, 11(3), 255; https://doi.org/10.3390/mi11030255 - 28 Feb 2020
Cited by 20 | Viewed by 4353
Abstract
Bloodstream infection with Candida fungal cells remains one of the most life-threatening complications among hospitalized patients around the world. Although most of the cases are still due to Candida albicans, the rising incidence of infections caused by other Candida strains that may [...] Read more.
Bloodstream infection with Candida fungal cells remains one of the most life-threatening complications among hospitalized patients around the world. Although most of the cases are still due to Candida albicans, the rising incidence of infections caused by other Candida strains that may not respond to traditional anti-fungal treatments merits the development of a method for species-specific isolation of Candida. To this end, here we present the characterization of the dielectrophoresis (DEP) response of Candida albicans, Candida tropicalis and Candida parapsilosis. We complement such characterization with a study of the Candida cells morphology. The Candida strains exhibited subtle differences in their morphology and dimensions. All the Candida strains exhibited positive DEP in the range 10–500 kHz, although the strength of the DEP response was different for each Candida strain at different frequencies. Only Candida tropicalis showed positive DEP at 750 kHz. The current results show potential for manipulation and enrichment of a specific Candida strain at specific DEP conditions towards aiding in the rapid identification of Candida strains to enable the effective and timely treatment of Candida infections. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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10 pages, 3338 KiB  
Article
Tunable-Focus Liquid Lens through Charge Injection
by Shizhi Qian, Wenxiang Shi, Huai Zheng and Zhaohui Liu
Micromachines 2020, 11(1), 109; https://doi.org/10.3390/mi11010109 - 20 Jan 2020
Cited by 5 | Viewed by 3796
Abstract
Liquid lenses are the simplest and cheapest optical lenses, and various studies have been conducted to develop tunable-focus liquid lenses. In this study, a simple and easily implemented method for achieving tunable-focus liquid lenses was proposed and experimentally validated. In this method, charges [...] Read more.
Liquid lenses are the simplest and cheapest optical lenses, and various studies have been conducted to develop tunable-focus liquid lenses. In this study, a simple and easily implemented method for achieving tunable-focus liquid lenses was proposed and experimentally validated. In this method, charges induced by a corona discharge in the air were injected into dielectric liquid, resulting in “electropressure” at the interface between the air and the liquid. Through a 3D-printed U-tube structure, a tunable-focus liquid lens was fabricated and tested. Depending on the voltage, the focus of the liquid lens can be adjusted in large ranges (−∞ to −9 mm and 13.11 mm to ∞). The results will inspire various new liquid-lens applications. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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14 pages, 4250 KiB  
Article
Electroosmotic Flow Behavior of Viscoelastic LPTT Fluid in a Microchannel
by Dilin Chen, Jie Li, Haiwen Chen, Lai Zhang, Hongna Zhang and Yu Ma
Micromachines 2019, 10(12), 881; https://doi.org/10.3390/mi10120881 - 15 Dec 2019
Cited by 7 | Viewed by 4133
Abstract
In many research works, the fluid medium in electroosmosis is considered to be a Newtonian fluid, while the polymer solutions and biological fluids used in biomedical fields mostly belong to the non-Newtonian category. Based on the finite volume method (FVM), the electroosmotic flow [...] Read more.
In many research works, the fluid medium in electroosmosis is considered to be a Newtonian fluid, while the polymer solutions and biological fluids used in biomedical fields mostly belong to the non-Newtonian category. Based on the finite volume method (FVM), the electroosmotic flow (EOF) of viscoelastic fluids in near-neutral (pH = 7.5) solution considering four ions (K+, Cl, H+, OH) is numerically studied, as well as the viscoelastic fluids’ flow characteristics in a microchannel described by the Linear Phan-Thien–Tanner (LPTT) constitutive model under different conditions, including the electrical double layer (EDL) thickness, the Weissenberg number (Wi), the viscosity ratio and the polymer extensibility parameters. When the EDL does not overlap, the velocity profiles for both Newtonian and viscoelastic fluids are plug-like and increase sharply near the charged wall. Compared with Newtonian fluid at Wi = 3, the viscoelastic fluid velocity increases by 5 times and 9 times, respectively, under the EDL conditions of kH = 15 and kH = 250, indicating the shear thinning behavior of LPTT fluid. Shear stress obviously depends on the viscosity ratio and different Wi number conditions. The EOF is also enhanced by the increase (decrease) in polymer extensibility parameters (viscosity ratio). When the extensibility parameters are large, the contribution to velocity is gradually weakened. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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15 pages, 11235 KiB  
Article
Dynamics Behaviors of Droplet on Hydrophobic Surfaces Driven by Electric Field
by Jie Liu and Sheng Liu
Micromachines 2019, 10(11), 778; https://doi.org/10.3390/mi10110778 - 14 Nov 2019
Cited by 10 | Viewed by 3888
Abstract
Droplet microfluidic technology achieves precise manipulation of droplet behaviors by designing and controlling the flow and interaction of various incompatible fluids. The electric field provides a non-contact, pollution-free, designable and promising method for droplet microfluidics. Since the droplet behaviors in many industrial and [...] Read more.
Droplet microfluidic technology achieves precise manipulation of droplet behaviors by designing and controlling the flow and interaction of various incompatible fluids. The electric field provides a non-contact, pollution-free, designable and promising method for droplet microfluidics. Since the droplet behaviors in many industrial and biological applications occur on the contact surface and the properties of droplets and the surrounding environment are not consistent, it is essential to understand fundamentally the sessile droplet motion and deformation under various conditions. This paper reports a technique using the pin-plate electrode to generate non-uniform dielectrophoresis (DEP) force to control sessile droplets on hydrophobic surfaces. The electrohydrodynamics phenomena of the droplet motion and deformation are simulated using the phase-field method. It is found that the droplet moves along the substrate surface to the direction of higher electric field strength, and is accompanied with a certain offset displacement. In addition, the effect of pin electric potentials, surface contact angles and droplet volumes on the droplet motion and deformation are also studied and compared. The results show that higher potentials, more hydrophobic surfaces and larger droplet volumes exhibit greater droplet horizontal displacement and offset displacement. But for the droplet vertical displacement, it is found that during the first revert process, the release of the surface tension can make the droplet with low potentials, small contact angles or small droplet volumes span from negative to positive. These results will be helpful for future operations encountered in sessile droplets under non-uniform electric fields towards the droplet microfluidics applications. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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10 pages, 5739 KiB  
Article
Electroosmotic Flow of Viscoelastic Fluid in a Nanochannel Connecting Two Reservoirs
by Lanju Mei and Shizhi Qian
Micromachines 2019, 10(11), 747; https://doi.org/10.3390/mi10110747 - 31 Oct 2019
Cited by 13 | Viewed by 3290
Abstract
Electroosmotic flow (EOF) of viscoelastic fluid with Linear Phan-Thien–Tanner (LPTT) constitutive model in a nanochannel connecting two reservoirs is numerically studied. For the first time, the influence of viscoelasticity on the EOF and the ionic conductance in the micro-nanofluidic interconnect system, with consideration [...] Read more.
Electroosmotic flow (EOF) of viscoelastic fluid with Linear Phan-Thien–Tanner (LPTT) constitutive model in a nanochannel connecting two reservoirs is numerically studied. For the first time, the influence of viscoelasticity on the EOF and the ionic conductance in the micro-nanofluidic interconnect system, with consideration of the electrical double layers (EDLs), is investigated. Regardless of the bulk salt concentration, significant enhancement of the flow rate is observed for viscoelastic fluid compared to the Newtonian fluid, due to the shear thinning effect. An increase in the ionic conductance of the nanochannel occurs for the viscoelastic fluid. The enhancement of the ionic conductance is significant under the overlapping EDLs condition. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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11 pages, 3377 KiB  
Article
Direct Numerical Simulation of Seawater Desalination Based on Ion Concentration Polarization
by Jie Li, Dilin Chen, Jian Ye, Lai Zhang, Teng Zhou and Yi Zhou
Micromachines 2019, 10(9), 562; https://doi.org/10.3390/mi10090562 - 25 Aug 2019
Cited by 11 | Viewed by 4023
Abstract
The problem of water shortage needs to be solved urgently. The membrane-embedded microchannel structure based on the ion concentration polarization (ICP) desalination effect is a potential portable desalination device with low energy consumption and high efficiency. The electroosmotic flow in the microchannel of [...] Read more.
The problem of water shortage needs to be solved urgently. The membrane-embedded microchannel structure based on the ion concentration polarization (ICP) desalination effect is a potential portable desalination device with low energy consumption and high efficiency. The electroosmotic flow in the microchannel of the cation exchange membrane and the desalination effect of the system are numerically analyzed. The results show that when the horizontal electric field intensity is 2 kV/m and the transmembrane voltage is 400 mV, the desalting efficiency reaches 97.3%. When the electric field strength increases to 20 kV/m, the desalination efficiency is reduced by 2%. In terms of fluid motion, under the action of the transmembrane voltage, two reverse eddy currents are formed on the surface of the membrane due to the opposite electric field and pressure difference on both sides of the membrane, forming a pumping effect. The electromotive force in the channel exhibits significant pressure-flow characteristics with a slip boundary at a speed approximately six times that of a non-membrane microchannel. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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13 pages, 3836 KiB  
Article
Analytical Solution of Time-Periodic Electroosmotic Flow through Cylindrical Microchannel with Non-Uniform Surface Potential
by Aminul Islam Khan and Prashanta Dutta
Micromachines 2019, 10(8), 498; https://doi.org/10.3390/mi10080498 - 26 Jul 2019
Cited by 11 | Viewed by 3282
Abstract
Time-periodic electroosmotic flow (EOF) with heterogeneous surface charges on channel walls can potentially be used to mix species or reagent molecules in microfluidic devices. Although significant research efforts have been placed to understand different aspects of EOF, its role in the mixing process [...] Read more.
Time-periodic electroosmotic flow (EOF) with heterogeneous surface charges on channel walls can potentially be used to mix species or reagent molecules in microfluidic devices. Although significant research efforts have been placed to understand different aspects of EOF, its role in the mixing process is still poorly understood, especially for non-homogeneous surface charge cases. In this work, dynamic aspects of EOF in a cylindrical capillary are analyzed for heterogeneous surface charges. Closed form analytical solutions for time-periodic EOF are obtained by solving the Navier–Stokes equation. An analytical expression of induced pressure is also obtained from the velocity field solution. The results show that several vortices can be formed inside the microchannel with sinusoidal surface charge distribution. These vortices change their pattern and direction as the electric field change its strength and direction with time. In addition, the structure and strength of the vorticity depend on the frequency of the external electric field and the size of the channel. As the electric field frequency or channel diameter increases, vortices are shifted towards the channel surface and the perturbed flow region becomes smaller, which is not desired for effective mixing. Moreover, the number of vorticities depends on the periodicity of the surface charge. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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10 pages, 1848 KiB  
Article
Analysis of Bacteriophages with Insulator-Based Dielectrophoresis
by Adriana Coll De Peña, Nurul Humaira Mohd Redzuan, Milky K. Abajorga, Nicole Hill, Julie A. Thomas and Blanca H. Lapizco-Encinas
Micromachines 2019, 10(7), 450; https://doi.org/10.3390/mi10070450 - 4 Jul 2019
Cited by 26 | Viewed by 4401
Abstract
Bacterial viruses or phages have great potential in the medical and agricultural fields as alternatives to antibiotics to control nuisance populations of pathogenic bacteria. However, current analysis and purification protocols for phages tend to be resource intensive and have numbers of limitations, such [...] Read more.
Bacterial viruses or phages have great potential in the medical and agricultural fields as alternatives to antibiotics to control nuisance populations of pathogenic bacteria. However, current analysis and purification protocols for phages tend to be resource intensive and have numbers of limitations, such as impacting phage viability. The present study explores the potential of employing the electrokinetic technique of insulator-based dielectrophoresis (iDEP) for virus assessment, separation and enrichment. In particular, the application of the parameter “trapping value” (Tv) is explored as a standardized iDEP signature for each phage species. The present study includes mathematical modeling with COMSOL Multiphysics and extensive experimentation. Three related, but genetically and structurally distinct, phages were studied: Salmonella enterica phage SPN3US, Pseudomonas aeruginosa phage ϕKZ and P. chlororaphis phage 201ϕ2-1. This is the first iDEP study on bacteriophages with large and complex virions and the results illustrate their virions can be successfully enriched with iDEP systems and still retain infectivity. In addition, our results indicate that characterization of the negative dielectrophoretic response of a phage in terms of Tv could be used for predicting individual virus behavior in iDEP systems. The findings reported here can contribute to the establishment of protocols to analyze, purify and/or enrich samples of known and unknown phages. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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25 pages, 10417 KiB  
Article
Multifrequency Induced-Charge Electroosmosis
by Kai Du, Jingni Song, Weiyu Liu, Ye Tao and Yukun Ren
Micromachines 2019, 10(7), 447; https://doi.org/10.3390/mi10070447 - 3 Jul 2019
Cited by 5 | Viewed by 3416
Abstract
We present herein a unique concept of multifrequency induced-charge electroosmosis (MICEO) actuated directly on driving electrode arrays, for highly-efficient simultaneous transport and convective mixing of fluidic samples in microscale ducts. MICEO delicately combines transversal AC electroosmotic vortex flow, and axial traveling-wave electroosmotic pump [...] Read more.
We present herein a unique concept of multifrequency induced-charge electroosmosis (MICEO) actuated directly on driving electrode arrays, for highly-efficient simultaneous transport and convective mixing of fluidic samples in microscale ducts. MICEO delicately combines transversal AC electroosmotic vortex flow, and axial traveling-wave electroosmotic pump motion under external dual-Fourier-mode AC electric fields. The synthetic flow field associated with MICEO is mathematically analyzed under thin layer limit, and the particle tracing experiment with a special powering technique validates the effectiveness of this physical phenomenon. Meanwhile, the simulation results with a full-scale 3D computation model demonstrate its robust dual-functionality in inducing fully-automated analyte transport and chaotic stirring in a straight fluidic channel embedding double-sided quarter-phase discrete electrode arrays. Our physical demonstration with multifrequency signal control on nonlinear electroosmosis provides invaluable references for innovative designs of multifunctional on-chip analytical platforms in modern microfluidic systems. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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13 pages, 2268 KiB  
Article
An Experimental Study of 3D Electrode-Facilitated Particle Traffic Flow-Focusing Driven by Induced-Charge Electroosmosis
by Tianyi Jiang, Ye Tao, Hongyuan Jiang, Weiyu Liu, Yansu Hu and Dewei Tang
Micromachines 2019, 10(2), 135; https://doi.org/10.3390/mi10020135 - 18 Feb 2019
Cited by 3 | Viewed by 3819
Abstract
In this paper we present a novel microfluidic approach for continuous, rapid and switchable particle concentration, using induced-charge electroosmosis (ICEO) in 3D electrode layouts. Field-effect control on non-linear electroosmosis in the transverse direction greatly facilitates a selective concentration of biological yeast cells from [...] Read more.
In this paper we present a novel microfluidic approach for continuous, rapid and switchable particle concentration, using induced-charge electroosmosis (ICEO) in 3D electrode layouts. Field-effect control on non-linear electroosmosis in the transverse direction greatly facilitates a selective concentration of biological yeast cells from a straight main microchannel into one of the three downstream branch channels in our microfluidic device. For the geometry configuration of 3D driving electrode plates on sidewalls and a 2D planar gate electrode strip on the channel bottom surface, we briefly describe the underlying physics of an ICEO-based particle flow-focusing method, and provide relevant simulation results to show how gate voltage amplitude can be used to guide the motion trajectory of the concentrated particle stream. With a relatively simple geometrical configuration, the proposed microfluidic device provides new possibilities to controllably concentrate micro/nanoparticles in continuous flow by using ICEO, and is suitable for a high-throughput front-end cell concentrator interfacing with various downstream biosensors. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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10 pages, 2121 KiB  
Article
Development of a High Flow Rate 3-D Electroosmotic Flow Pump
by Zi Ye, Renchang Zhang, Meng Gao, Zhongshan Deng and Lin Gui
Micromachines 2019, 10(2), 112; https://doi.org/10.3390/mi10020112 - 11 Feb 2019
Cited by 17 | Viewed by 3532
Abstract
A low voltage 3D parallel electroosmotic flow (EOF) pump composed of two electrode layers and a fluid layer is proposed in this work. The fluid layer contains twenty parallel fluid channels and is set at the middle of the two electrode layers. The [...] Read more.
A low voltage 3D parallel electroosmotic flow (EOF) pump composed of two electrode layers and a fluid layer is proposed in this work. The fluid layer contains twenty parallel fluid channels and is set at the middle of the two electrode layers. The distance between fluid and electrode channels was controlled to be under 45 μm, to reduce the driving voltage. Room temperature liquid metal was directly injected into the electrode channels by syringe to form non-contact electrodes. Deionized (DI) water with fluorescent particles was used to test the pumping performance of this EOF pump. According to the experimental results, a flow rate of 5.69 nL/min was reached at a driving voltage of 2 V. The size of this pump is small, and it shows a great potential for implanted applications. This structure could be easily expanded for more parallel fluid channels and larger flow rate. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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11 pages, 2502 KiB  
Article
Multi-Stage Particle Separation based on Microstructure Filtration and Dielectrophoresis
by Danfen Yin, Xiaoling Zhang, Xianwei Han, Jun Yang and Ning Hu
Micromachines 2019, 10(2), 103; https://doi.org/10.3390/mi10020103 - 31 Jan 2019
Cited by 22 | Viewed by 4366
Abstract
Particle separation is important in chemical and biomedical analysis. Among all particle separation approaches, microstructure filtration which based particles size difference has turned into one of the most commonly methods. By controlling the movement of particles, dielectrophoresis has also been widely adopted in [...] Read more.
Particle separation is important in chemical and biomedical analysis. Among all particle separation approaches, microstructure filtration which based particles size difference has turned into one of the most commonly methods. By controlling the movement of particles, dielectrophoresis has also been widely adopted in particle separation. This work presents a microfluidic device which combines the advantages of microfilters and dielectrophoresis to separate micro-particles and cells. A three-dimensional (3D) model was developed to calculate the distributions of the electric field gradient at the two filter stages. Polystyrene particles with three different sizes were separated by micropillar array structure by applying a 35-Vpp AC voltage at 10 KHz. The blocked particles were pushed off the filters under the negative dielectrophoretic force and drag force. A mixture of Haematococcus pluvialis cells and Bracteacoccus engadinensis cells with different sizes were also successfully separated by this device, which proved that the device can separate both biological samples and polystyrene particles. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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12 pages, 3488 KiB  
Article
An Exact Solution for Power-Law Fluids in a Slit Microchannel with Different Zeta Potentials under Electroosmotic Forces
by Du-Soon Choi, Sungchan Yun and WooSeok Choi
Micromachines 2018, 9(10), 504; https://doi.org/10.3390/mi9100504 - 5 Oct 2018
Cited by 9 | Viewed by 2874
Abstract
Electroosmotic flow (EOF) is one of the most important techniques in a microfluidic system. Many microfluidic devices are made from a combination of different materials, and thus asymmetric electrochemical boundary conditions should be applied for the reasonable analysis of the EOF. In this [...] Read more.
Electroosmotic flow (EOF) is one of the most important techniques in a microfluidic system. Many microfluidic devices are made from a combination of different materials, and thus asymmetric electrochemical boundary conditions should be applied for the reasonable analysis of the EOF. In this study, the EOF of power-law fluids in a slit microchannel with different zeta potentials at the top and bottom walls are studied analytically. The flow is assumed to be steady, fully developed, and unidirectional with no applied pressure. The continuity equation, the Cauchy momentum equation, and the linearized Poisson-Boltzmann equation are solved for the velocity field. The exact solutions of the velocity distribution are obtained in terms of the Appell’s first hypergeometric functions. The velocity distributions are investigated and discussed as a function of the fluid behavior index, Debye length, and the difference in the zeta potential between the top and bottom. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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21 pages, 4922 KiB  
Article
A High-Throughput Electrokinetic Micromixer via AC Field-Effect Nonlinear Electroosmosis Control in 3D Electrode Configurations
by Kai Du, Weiyu Liu, Yukun Ren, Tianyi Jiang, Jingni Song, Qian Wu and Ye Tao
Micromachines 2018, 9(9), 432; https://doi.org/10.3390/mi9090432 - 26 Aug 2018
Cited by 16 | Viewed by 3897
Abstract
In this study, we make use of the AC field-effect flow control on induced-charge electroosmosis (ICEO), to develop an electrokinetic micromixer with 3D electrode layouts, greatly enhancing the device performance compared to its 2D counterpart of coplanar metal strips. A biased AC voltage [...] Read more.
In this study, we make use of the AC field-effect flow control on induced-charge electroosmosis (ICEO), to develop an electrokinetic micromixer with 3D electrode layouts, greatly enhancing the device performance compared to its 2D counterpart of coplanar metal strips. A biased AC voltage wave applied to the central gate terminal, i.e., AC field-effect control, endows flow field-effect-transistor of ICEO the capability to produce arbitrary symmetry breaking in the transverse electrokinetic vortex flow pattern, which makes it fascinating for microfluidic mixing. Using the Debye-Huckel approximation, a mathematical model is established to test the feasibility of the new device design in stirring nanoparticle samples carried by co-flowing laminar streams. The effect of various experimental parameters on constructing a viable micromixer is investigated, and an integrated microdevice with a series of gate electrode bars disposed along the centerline of the channel bottom surface is proposed for realizing high-flux mixing. Our physical demonstration on field-effect nonlinear electroosmosis control in 3D electrode configurations provides useful guidelines for electroconvective manipulation of nanoscale objects in modern microfluidic systems. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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Review

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20 pages, 1311 KiB  
Review
Organs-on-a-Chip Module: A Review from the Development and Applications Perspective
by Juan Eduardo Sosa-Hernández, Angel M. Villalba-Rodríguez, Kenya D. Romero-Castillo, Mauricio A. Aguilar-Aguila-Isaías, Isaac E. García-Reyes, Arturo Hernández-Antonio, Ishtiaq Ahmed, Ashutosh Sharma, Roberto Parra-Saldívar and Hafiz M. N. Iqbal
Micromachines 2018, 9(10), 536; https://doi.org/10.3390/mi9100536 - 22 Oct 2018
Cited by 172 | Viewed by 14412
Abstract
In recent years, ever-increasing scientific knowledge and modern high-tech advancements in micro- and nano-scales fabrication technologies have impacted significantly on various scientific fields. A micro-level approach so-called “microfluidic technology” has rapidly evolved as a powerful tool for numerous applications with special reference to [...] Read more.
In recent years, ever-increasing scientific knowledge and modern high-tech advancements in micro- and nano-scales fabrication technologies have impacted significantly on various scientific fields. A micro-level approach so-called “microfluidic technology” has rapidly evolved as a powerful tool for numerous applications with special reference to bioengineering and biomedical engineering research. Therefore, a transformative effect has been felt, for instance, in biological sample handling, analyte sensing cell-based assay, tissue engineering, molecular diagnostics, and drug screening, etc. Besides such huge multi-functional potentialities, microfluidic technology also offers the opportunity to mimic different organs to address the complexity of animal-based testing models effectively. The combination of fluid physics along with three-dimensional (3-D) cell compartmentalization has sustained popularity as organ-on-a-chip. In this context, simple humanoid model systems which are important for a wide range of research fields rely on the development of a microfluidic system. The basic idea is to provide an artificial testing subject that resembles the human body in every aspect. For instance, drug testing in the pharma industry is crucial to assure proper function. Development of microfluidic-based technology bridges the gap between in vitro and in vivo models offering new approaches to research in medicine, biology, and pharmacology, among others. This is also because microfluidic-based 3-D niche has enormous potential to accommodate cells/tissues to create a physiologically relevant environment, thus, bridge/fill in the gap between extensively studied animal models and human-based clinical trials. This review highlights principles, fabrication techniques, and recent progress of organs-on-chip research. Herein, we also point out some opportunities for microfluidic technology in the future research which is still infancy to accurately design, address and mimic the in vivo niche. Full article
(This article belongs to the Special Issue Micro/Nano-Chip Electrokinetics, Volume III)
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