Dielectrophoretic Effect Research Articles

Separating the Living from the Dead: An Electrophoretic Approach.

Cell viability studies are essential in numerous applications, including drug development, clinical analysis, bioanalytical assessments, food safety, and environmental monitoring. Microfluidic electrokinetic (EK) devices have been proven to be effective platforms to discriminate microorganisms by their viability status. Two decades ago, live and dead Escherichia coli (E. coli) cells were trapped at distinct locations in an insulator-based EK (iEK) device with cylindrical insulating posts. At that time, the discrimination between live and dead cells was attributed to dielectrophoretic effects. This study presents the continuous separation between the live and dead E. coli cells, which was achieved primarily by combining linear and nonlinear electrophoretic effects in an iEK device. First, live and dead E. coli cells were characterized in terms of their electrophoretic migration, and then the properties of both live and dead E. coli cells were input into a mathematical model built using COMSOL Multiphysics software to identify appropriate voltages for performing an iEK separation in a T-cross iEK channel. Subsequently, live and dead cells were successfully separated experimentally in the form of an electropherogram, achieving a separation resolution of 1.87. This study demonstrated that linear and nonlinear electrophoresis phenomena are responsible for the discrimination between live and dead cells under DC electric fields in iEK devices. Continuous electrophoretic assessments, such as the one presented here, can be used to discriminate between distinct types of microorganisms including live and dead cell assessments.

Dielectrophoretic separation of a water-in-oil emulsion

Electric field-assisted separation is considered one of the most effective ways of dehydrating water-in-oil emulsions. In the uniform electric field usually used in electrodehydrators, electrocoalescence leads to droplet enlargement, thus accelerating their gravitational settling. Meanwhile, using a nonuniform field is expected to provide an additional tool for phase spatial separation due to dielectrophoresis while keeping the conditions favorable for electrocoalescence. This study aims to investigate experimentally the dynamics of water-in-oil emulsion in a nonuniform electric field and the efficiency of its separation due to the dielectrophoretic effect. A high-frequency field and emulsions with zero-density contrast were used allowing us to study the action of the dielectrophoretic force in the absence of electrokinetic phenomena and gravitational settling. We found that droplets always move towards the electric field strength gradient, eventually accumulating at the internal electrode. We demonstrate that the separation efficiency increases as the average droplet size, the voltage, the dispersion medium permittivity, and the initial droplet concentration increase. In the latter case the separation enhancement is due primarily to droplet coalescence, the rate of which increases appreciably with increasing concentration. We demonstrate that all the experimental results can be combined into unified dependence based on a simple physical model.

A universal AC electrokinetics-based strategy toward surface antifouling of underwater optics

The practical applications of underwater optical devices, such as cameras or sensors, often suffer from widespread surface biofouling. Current antifouling techniques are primarily hindered by low efficiency, poor compatibility, as well as environmental pollution issues. This paper presents a transparent electrode coating as antifouling system of underwater optics as potential substitute for alternating current electrokinetic (ACEK)-based systems. A strong-coupling model is established to predict the Joule heating induced fluid flows and the negative dielectrophoretic (nDEP) effect for mobilizing organisms or deposited sediments on optic surfaces. The performance of the proposed antifouling system is numerically evaluated through simulations of electrostatic, fluid and temperature fields as well as trajectories of submicron particles, which is then experimentally verified and found to be in good agreement. A parametric study revealed that the degree of electrodes asymmetry is the key factor affecting the flow pattern and therefore the overall performance of the system. This ACEK-based universal strategy is expected to shed light on designing high performance and non-toxic platforms toward energy-efficient surface antifouling applications of underwater optics.

Effects of finite counterion size and nonhomogeneous permittivity and viscosity of the solution on the electrokinetics of a concentrated salt-free colloid.

In the present work, a general model of the electrokinetics and dielectric response of a concentrated salt-free colloid is developed which includes consideration of the finite size of the counterions released by the particles to the solution, a nonhomogeneous permittivity of the solution, the existence of Born and dielectrophoretic forces acting on the counterions, and especially the fact that the solution viscosity and diffusion counterion coefficient are allowed to be functions of the local counterion concentration. These effects have recently been discussed by J. J. López-García etal. [Phys. Rev. Fluids 4, 103702 (2019)10.1103/PhysRevFluids.4.103702] in the case of dilute colloids in general electrolyte solutions. The objective of this work is to explore the new effects and their influence on the electrokinetic response of concentrated salt-free systems. Present results confirm previous findings regarding the important increases of the dc electrophoretic mobility and dc electrical conductivity, as well as huge increments of the dynamic electrophoretic mobilities at high frequencies when finite-ion-size effects were taken into account. In addition, consideration of the viscosity of the solution and of the counterion diffusion coefficient as functions of the local counterion concentration leads to a decrease of the magnitude of the previous electrokinetic results. The theory incorporates a more convenient hard-sphere hydrodynamic model to account for the nonhomogeneous viscosity of the solution than others proposed in previous works in the literature. A comparison is elaborated on between electrokinetic and dielectric responses with different levels of complexity of the theoretical model, starting from the case of pointlike counterions and following with the inclusion in sequence of additional aspects such as finite counterion size, nonhomogeneous electrical permittivity with associated Born and dielectrophoretic effects, and, finally, position-dependent viscosity and diffusion counterion coefficient, and clearly shows the influence of individual effects on the general electrokinetic response and especially the relevant role the nonhomogeneous viscosity on the dc and ac electrokientic behavior of salt-free colloids.

Research on High‐Efficiency Curved Surface Polishing with Even Distribution of Slurry Based on Dielectrophoresis

To overcome the problems of low slurry utilization and poor surface uniformity in conventional small tool polishing of curved surfaces, a small tool polishing method based on slurry dielectrophoresis (STP‐DEP) is proposed. The dielectrophoretic effect distributes the slurry evenly and increases its dwell time in the processing area, enabling more abrasives to participate in polishing, thereby improving the material removal efficiency and surface uniformity of the workpiece. The observation experiment indicates that dielectrophoresis can efficiently distribute the slurry evenly. Compared with the traditional small tool polishing, the results show that the polishing efficiency of the STP‐DEP is improved by 34% on the premise of achieving the same surface roughness Ra of the workpiece. The Taguchi experiments are carried out on K9 convex lens. Results show that the optimal surface roughness Ra 3.3 nm (initial Ra 2400 nm, processing time 120 min) is obtained when the tool speed is 400 rpm, the pressing amount is 1 mm, the infeed angle is 15°, and the abrasive size is 3 μm. The research proves that the STP‐DEP successfully solves the problem of slurry uneven distribution, and realizes efficient surface polishing with high surface uniformity.

Design and analysis of biconvex liquid lens with circular hole plate electrode structure

In this paper, based on the research of zoom liquid lens with parallel plate electrode and the principle of dielectrophoresis, a model of the biconvex liquid lens with circular hole plate electrode structure is proposed, which is a novel three-layer liquid lens structure. The dielectrophoretic effect refers to the phenomenon that free dielectric molecules will be polarized and moved by the force in a non-uniform electric field, thus deforming the dielectric liquid. In the dielectrophoretic liquid lens, only two insulating liquid materials with large refractive index difference and dielectric constant difference need to be selected, which can increase the selection range of liquid materials. The liquid lens structure mainly consists of a piece of double-sided conductive flat plate ITO glass with a circular hole and two pieces of single-sided conductive flat plate ITO glass, which respectively form two sets of flat electrode structures to control the upper interface and lower interface of the liquid droplet. In this structure, the influences of the intermediate glass plate on the focus and imaging are reduced by using the flat plate electrode with circular hole. The theoretical analysis of the structure is carried out with simulation software. Firstly, the models of the biconvex liquid lens with circular hole plate electrode under different voltages are built with Comsol software, the data of upper interface and lower interface of the liquid droplet are exported. Then by using Matlab, the surface shapes of the upper interface and lower interface of the droplet are fitted and the corresponding aspheric coefficients are obtained. Finally, the optical models are built with Zemax software, the imaging optical paths and the variation range of focal length under different voltages are analyzed. On the basis of the simulation, the corresponding device is made, and the specific experimental analysis is carried out. The surface patterns of the upper interface and lower interfaces of the droplet of the biconvex liquid lens under different voltages are recorded, the focal length and imaging resolution of the liquid lens are measured. When the operating voltage is in a range of 0–260 V, the focal length varies from 23.8–17.5 mm, which is basically consistent with the simulation results (22.6–15.9 mm). The feasibility of the structure of the biconvex liquid lens with circular hole plate electrode structure is verified experimentally. The imaging resolution can reach 45.255 lp/mm. The results show that this proposed novel three-layer liquid structure of the biconvex liquid lens has the characteristics of simple structure, easy-to-realize and good imaging quality. Therefore, the research of this biconvex liquid lens can provide a new idea for expanding the high-resolution imaging research of liquid lenses and their applications.

Dielectrophoretic Movement of Cell Passing Between Surface Electrodes in Flow Channel

Abstract In this study, cell behavior in a microchannel was tracked for the application of dielectrophoresis to biological cell sorting. A pair of titanium surface electrodes was fabricated inside the microchannel by photolithographic techniques: a triangular electrode with a tip angle of 0.26 rad and a rectangular electrode. A periodic alternating current of square wave with a period of 1 μs was introduced between the electrodes to induce an asymmetric electric field perpendicular to the mainstream direction. The behavior of mouse myoblasts (C2C12: mouse myoblast cell line) was measured in vitro while the suspension was flowing. The relationship between cell shift motion near the electrode and cell shape on the two-dimensional projection plane was investigated. Experimental results showed that cell movement in the direction perpendicular to the mainstream increased with geometries away from the circle in the two-dimensional projection plane. This method can be applied to sort cells according to their degree of shape deviation from a sphere. The dielectrophoretic effect can be applied to sort cells not only by cell size but also by cell deformation.

Film boiling suppression and boiling heat transfer enhancement by dielectrophoretic effect

Film boiling suppression and boiling heat transfer enhancement by dielectrophoretic effect

Design and analysis of aspherical double-liquid lens based on planar electrode

In order to study an aspherical liquid lens with simple structure and easy realization, an aspherical double-liquid lens based on planar electrode is designed based on the dielectrophoretic effect. The droplet in the dielectric electrophoretic liquid lens is polarized in the electric field and moves towards the higher electric field strength under the action of the dielectrophoresis force. With the change of the applied voltage, the dielectrophoresis force also changes, thus the contact angle of the droplet at the solid-liquid interface changes. Firstly, the models of the aspherical double-liquid lens under different voltages are established with Comsol software, and the interfacial profile data are obtained. Then the aspherical coefficients and the surface type of the fitted interface are obtained with Matlab software. Finally, the corresponding optical model of double-liquid lens is established with Zemax software. The variable range of focal lengths and root mean square (RMS) radii of the aspherical double-liquid lens at different voltages are obtained. In order to further study the characteristics of the aspherical double-liquid lens, it is compared with a spherical double-liquid lens model. Based on the contact angle theory of liquid lens and Gaussian optics theory, the relationship between the interfacial curvature radius of the spherical liquid lens and the applied voltage, and the relationship between the focal length and the applied voltage are obtained, respectively. The liquid material, cavity structure and droplet are the same as those of the aspherical lens. The corresponding spherical double-liquid lens model is established according to the two expressions relating to Zemax, and the voltage value is the same as that of the aspherical lens. Thus, the variable ranges of focal length and RMS radius in the spot diagram of the spherical double-liquid lenses at different voltages are obtained. Then, they are compared with those of aspherical double-liquid lens, and the results show that the variable range of focal length of the aspherical double-liquid lens is larger than that of the spherical double-liquid lens, and the imaging quality of the former is better than that of the latter. Moreover, through the device fabrication and preliminary experimental analysis of the aspherical double-liquid lens, the imaging resolution can reach 40.318 lp/mm. The aspherical double-liquid lens proposed in this work has the characteristics of simple structure and easy realization, which can provide a new scheme for high-quality imaging of liquid lens and its applications, and can expand the application scope of liquid lens.

Design and analysis of the biconvex liquid lens with circular hole plate electrode structure

In this paper, based on the research of zoom liquid lens with parallel plate electrode and the principle of dielectrophoresis, a model of the biconvex liquid lens with circular hole plate electrode structure is proposed, which is a novel three-layer liquid lens structure. The dielectrophoretic effect refers to the phenomenon that free dielectric molecules will be polarized and moved by the force in a non-uniform electric field, thus deforming the dielectric liquid. In the dielectrophoretic liquid lens, only two insulating liquid materials with large refractive index difference and dielectric constant difference need to be selected, which can increase the selection range of liquid materials. The liquid lens structure mainly consists of a piece of double-sided conductive flat plate ITO glass with a circular hole and two pieces of single-sided conductive flat plate ITO glass, which respectively form two sets of flat electrode structures to control the upper and lower interfaces of the liquid droplet. In this structure, the influence of the intermediate glass plate on the focus and imaging is reduced by using the flat plate electrode with circular hole. The theoretical analysis of the structure is carried out with simulation software. Firstly, the models of the biconvex liquid lens with circular hole plate electrode under different voltages are built with Comsol software, the data of upper and lower interfaces of the liquid droplet are exported. Then by using Matlab, the surface shapes of the upper and lower interfaces of the droplet are fitted and the corresponding aspheric coefficients are obtained. Finally, the optical models are built with Zemax software, the imaging optical paths and the variation range of focal length under different voltages are analyzed. On the basis of the simulation, the corresponding device is manufactured, and the specific experimental analysis is carried out. The surface pattern of the upper and lower interfaces of the droplet of the biconvex liquid lens under different voltages are recorded, the focal length and imaging resolution of the liquid lens are measured. When the operating voltage is 0V-260V, the focal length varies from 23.8mm to 17.5mm, which is basically consistent with the simulation results(22.6mm-15.9mm). The feasibility of the structure of the biconvex liquid lens with circular hole plate electrode structure is verified by experiments. The imaging resolution can reach 45.255 lp/mm. The results show that this proposed novel three-layer liquid structure of the biconvex liquid lens has the characteristics of simple structure, easy to realize and good imaging quality. Therefore, the research of this biconvex liquid lens can provide a new idea for expanding the high-resolution imaging research of liquid lenses and their applications.

Динамика водомасляной эмульсии в неоднородном высокочастотном электрическом поле

The article presents the results of an experimental and numerical study of the behavior of a water-oil emulsion in an inhomogeneous electric field conducted to investigate the prospects of using the dielectrophoretic effect for the separation of liquid dispersed media. The problem is considered under conditions of neutral buoyancy of the dispersed phase, when the dynamics of droplet inclu-sions is determined solely by the action of the dielectrophoretic force. The inhomogeneous electric field was created by a system of coaxial cylindrical electrodes. The experiments were carried out in an alternating electric field with a frequency of 10 kHz, which made it possible to avoid the mani-festation of electrophoretic and electrokinetic phenomena. We studied both the dynamics of indi-vidual droplets in an electric field and the change in the content of the dispersed phase at different moments of time. It was found that water droplets always move in the direction of the intensity gradient, eventually accumulating on the internal electrode. The time it takes a single drop to reach the inner electrode significantly depends on its size and the initial distance to the inner electrode, the magnitude of the effective voltage, and the permittivity of the dispersion medium. It is shown that when choosing the initial distance from the drop to the inner electrode and the total time of the drop movement as measurement units for the current distance and time, respectively, the results of all experiments form a single dependence in these dimensionless variables. It was found that the emulsion separation rate increases with an increase in the average droplet size, the effective volt-age, the dielectric constant of the dispersion medium and the initial concentration of droplets. It is shown that in the latter case, the dependence is due to the presence of cases of droplet coalescence, the frequency of which increases with increasing concentration. The results obtained during numer-ical simulation are in good quantitative agreement with the experiment. In conclusion, the results of the laboratory and numerical experiments are compared, the advantages of the proposed method of electrodehydration in comparison with existing approaches are discussed.

Dielectrophoresis-Based SERS Sensors for the Detection of Cancer Cells in Microfluidic Chips.

The detection of freely circulating cancer cells (CTCs) is one of the greatest challenges of modern medical diagnostics. For several years, there has been increased attention on the use of surface-enhanced Raman spectroscopy (SERS) for the detection of CTCs. SERS is a non-destructive, accurate and precise technique, and the use of special SERS platforms even enables the amplification of weak signals from biological objects. In the current study, we demonstrate the unique arrangement of the SERS technique combined with the deposition of CTCs cells on the surface of the SERS platform via a dielectrophoretic effect. The appropriate frequencies of an alternating electric field and a selected shape of the electric field can result in the efficient deposition of CTCs on the SERS platform. The geometry of the microfluidic chip, the type of the cancer cells and the positive dielectrophoretic phenomenon resulted in the trapping of CTCs on the surface of the SERS platform. We presented results for two type of breast cancer cells, MCF-7 and MDA-MB-231, deposited from the 0.1 PBS solution. The limit of detection (LOD) is 20 cells/mL, which reflects the clinical potential and usefulness of the developed approach. We also provide a proof-of-concept for these CTCs deposited on the SERS platform from blood plasma.

Detection of prostate specific antigen in whole blood by microfluidic chip integrated with dielectrophoretic separation and electrochemical sensing

The efficient detection of cancer markers has faced many challenges, such as severe interference, complicated and time-consuming operation, low sensitivity and so on. In this paper, a microfluidic chip integrated with electrodes for dielectrophoretic (DEP) separation, microchannels for electrochemical nanoprobes binding and differential pulse voltammetry (DPV) detection was proposed for the sensitive and rapid detection of prostate specific antigen (PSA) in whole blood. The functional units, which could realize cell separation, PSA derivatization (binding of electrochemical nanoprobes), capture and detection, were integrated on the microfluidic chip. The well-designed V-shaped interdigital electrode arrays provided DEP separation for blood cells with efficiency as high as 98%. Particularly, DEP effect significantly improved the sensitivity of PSA detection and reduced the detection limit by two orders of magnitude. In order to achieve sensitive detection of PSA, binding of electrochemical nanoprobes and then DPV detection was selected and integrated following the DEP separation. A sandwich structure based on electrochemical nanoprobes and dual-aptamers for on-chip DPV detection was proposed, which included self-synthesized electrochemical nanoprobes bovine serum albumin/detection aptamer 2/polythionine@gold nanoparticles (BSA/Apt2/PThi@Au NPs), target PSA, and sensing interface 6-mercaptohexanol/capture aptamer 1/gold nanoparticles on gold electrode (MCH/Apt1/Au NPs/Au). The method of quantitative detection of PSA in whole blood was then established. The excellent performance of the microfluidic chip allowed the determination of PSA in whole blood in the range of 1 pg/mL ∼10 ng/mL with an ultralow limit of detection of 0.25 pg/mL, which was better than the results obtained by conventional methods.

Front Cover: Enhancing affinity‐based electroanalytical biosensors by integrated AC electrokinetic enrichment—A mini review

DOI: 10.1002/elps.202100168 The cover picture shows how affinity-based electroanalytical biosensors can be enhanced by integrated AC electrokinetic (ACEK) effects. ACEK effects, including AC electrothermal (ACET) effect, AC electroosmosis (ACEO) effect and dielectrophoretic (DEP) effect, are produced by applying AC signals to the interdigitated electrode arrays. ACEK effects induce directed movement of microflows and particles (e.g., proteins, nucleic acids, bacteria, small molecules, etc.) in the solution, so that the analytes in the solution can be quickly routed toward the surface of biosensors, thus improving the binding efficiency between the analytes and the probes on the surface of the sensor. Studies have shown that the method holds great promise for achieving high sensitivity, low detection limit and rapid turnaround.

Numerical investigation of atmospherelike flows in a spherical geometry.

Buoyancy-driven convection flows play a crucial role in global heat and momentum transport in atmosphere. Simplified planetary and stellar atmospheres can be described by a spherical gap geometry with special boundary conditions for the temperature. In the spherical gap, the dielectrophoretic effect is used to synthesize the radial gravity field. Lateral thermal boundary conditions are used to model solar radiation at the equator and at the poles. The temperature reaches a maximum value at the equator and becomes colder near the poles. In the case of a rotating gap, the influence of the Coriolis and centrifugal forces are taken into account. Different regimes of the two-dimensional steady basic flow are discussed in dependence on the Taylor number and Rayleigh number and for the radii ratio η=R_{in}/R_{out}, where R_{in},R_{out} are the radii of the inner and outer surfaces, respectively. Linear instability theory is used to study when the basic flow becomes unstable. The critical Rayleigh number at which the steady axisymmetric basic flow becomes time-dependently axisymmetric or three dimensional is found to be a function of the Taylor number. Furthermore, the critical azimuthal wave number m_{c}, which is responsible for the structure of the supercritical three-dimensional flow, and the critical frequency of the perturbation ω_{c} were found. The spatial location of the perturbation helps to understand the origin of the instability.

Dielectrophoretic Trapping for Nanoparticles, High-Molecule-Weight DNA, and SYBR Gold Using Polyimide-Based Printed Circuit Board

Microelectrodes for electrokinetic detection have been employed to manipulate and collect nanomaterials and biomaterials. However, the process of microelectrode patterning has been researched in the semiconductor fabrication process, which is expensive and time-consuming. Here, we demonstrate dielectrophoretic trapping of 200 nm fluorescent polystyrene nanoparticles and λ-deoxyribonucleic acid with SYBR gold using dielectrophoretic trapping onto an interdigitated circular electrode (ICE). For dielectrophoretic trapping, an ICE is designed and an ordered flexible printed circuit board (FPCB), possessing a non-porous polyimide substrate, is constructed. The ICE FPCB could identify the dielectrophoretic trapping conditions and simulate them by the finite element method. The fluorescent molecules in the ICE FPCB are dielectrophoretically trapped at the finger edges of the ICE when a peak-to-peak voltage of 12 V is applied at 6 kHz for 15-20 min. Moreover, monitoring of the dielectrophoretic trapping effect of SYBR gold eliminated the false negative detection error.

Solvent-mediated forces in protein dielectrophoresis.

DEP is an established method to manipulate micrometer-sized particles, but standard continuum theories predict only negligible effects for nanometer-sized proteins despite contrary experimental evidence. A theoretical description of protein DEP needs to consider details on the molecular scale. Previous work toward this goal addressed the role of orientational polarization of static protein dipole moments for dielectrophoretic effects, which successfully predicts the general magnitude of dielectrophoretic forces on proteins but does not readily explain negative DEP forces observed for proteins in some experiments. However, contributions to the protein chemical potential due to protein-water interactions have not yet been considered in this context. Here, we utilize atomistic molecular dynamics simulations to evaluate polarization-induced changes in the protein solvation free energy, which result in a solvent-mediated contribution to dielectrophoretic forces. We quantify solvent-mediated dielectrophoretic forces for two proteins and a small peptide in water, which follow expectations for protein-water dipole-dipole interactions. The magnitude of solvent-mediated dielectrophoretic forces exceeds predictions of nonmolecular continuum theories, but plays a minor role for the total dielectrophoretic force for the simulated proteins due to dominant contributions from the orientational polarization of their static protein dipoles. However, we extrapolate that solvent-mediated contributions to negative protein DEP forces will become increasingly relevant for multidomain proteins, complexes and aggregates with large protein-water interfaces, as well as for high electric field frequencies, which provides a potential mechanism for corresponding experimental observations of negative proteinDEP.

Mediation of lubricated air films using spatially periodic dielectrophoretic effect

A stone thrown in a lake captures air as it collides with water and sinks; likewise a rain drop falling on a flat surface traps air bubbles underneath and creates a spectacular splash. These natural occurrences, from bubble entrapment to liquid ejection, happen as air fails to escape from the closing gap between liquid and solid surfaces. Trapping of air is devastating for casting, coating, painting, and printing industries, or those intolerant of water entry noise. Attempts to eliminate the interfering air rely on either reducing the ambient pressure or modifying the solid surfaces. The former approach is inflexible in its implementation, while the latter one is inherently limited by the wetting speed of liquid or the draining capacity of air passages created on the solid. Here, we present a “divide and conquer” approach to split the thin air gap into tunnels and subsequently squeeze air out from the tunnels against its viscous resistance using spatially periodic dielectrophoretic force. We confirm the working principles by demonstrating suppression of both bubble entrapment and splash upon impacts of droplets on solid surfaces.

Multiphase lattice Boltzmann modeling of dielectrophoresis fractionation of soft particles

Dielectrophoresis-field flow fractionation (DEP-FFF) is a promising method of fractionating particles from a continuous flow and has considerable application potential in the fields of biomedical, chemical, and environmental engineering. Particle deformation is an important issue in DEP-FFF, having a critical influence on the fractionation accuracy and viability of bioparticles. However, this problem has been largely ignored in both theoretical and numerical investigations. In the present work, a hybrid lattice Boltzmann scheme is introduced to study the deformation of soft particles subjected to the coupled effects of hydrodynamics and electrokinetics in a DEP-FFF process. The interaction of the particles with the fluid medium is calculated using a multiphase lattice Boltzmann model. The dielectrophoretic effect on the flow is introduced through a DEP force, which is obtained from a finite-element solution of the electric field. The hybrid scheme avoids the need to solve a coupled multiphysics problem, making it very efficient. The proposed simulation framework is validated through a well-known model, and the particle deformation and its influence on DEP-based fractionation are discussed.

Biosensors Based on SOI Nanowire Transistors for Biomedicine and Virusology

This article contains the results of research on the topical problem of highly sensitive express registration of biological objects using field-effect transistors with the surface open for analyte access, which are made based on silicon-on-insulator (SOI) films. The possibilities of dielectrophoretic effects for controlling the concentration of the analyte in the area of sensory elements are considered on the example of the indication of viruses of nuclear polyhedrosis and vaccinia. It is shown that the use of the dielectrophoresis (DEPh) effect makes it possible to solve (1) the key tasks for creating sensor systems: increasing the detecting ability, as well as exrtacting and verifying the signal from the target particles; and (2) the fundamental task: determining the charge state of the analyte in solutions without modifying the sensors’ surface. The problems and prospects of the mass application of nanowire (NW) biosensors, including those with the dielectrophoretic effect, in biotechnology, virology, etc., are discussed.