Effect of direct current dielectrophoresis on the trajectory of a non‐conducting colloidal sphere in a bent pore

House, Dustin; Luo, H. L.

doi:10.1002/elps.201100323

Cited by 9 publications

(8 citation statements)

References 37 publications

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“…When the particle enters the constriction where the electric field becomes highly nonuniform (Fig. B), the DEP force points toward the upper stream direction and tends to retard the motion of the incoming particle . However, since the Stokes force is two orders of magnitude higher than the DEP force, the particle still moves forward into the aperture with the carrying liquid.…”

Section: Resultsmentioning

confidence: 88%

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3D numerical simulation of a Coulter counter array with analysis of electrokinetic forces

et al. 2012

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Coulter counters have played an important role in biological cell assays since their introduction decades ago. Several types of high throughput micro-Coulter counters based on lab-on-chip devices have been commercialized recently. In this paper, we propose a highly integrated micro-Coulter counter array working under low DC voltage. The real-time electrical current change, including the pulse amplitude and width, of the micro-Coulter counter with novel structure is systematically investigated numerically. The major types of forces exerted on the particle in the micro-Coulter counter, including hydrodynamic force and electrokinetic force are quantitatively analyzed. The simulation in this study shows the pulse profile, such as width and amplitude, is affected by both particle size and the flow condition. The special cases of multiple particle aggregation and cross-talk between neighboring channels are also considered for their effects on the electric current pulses. This simulation provides critical insight and guidance for developing next new generations of micro-Coulter counter.

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Section: Resultsmentioning

confidence: 88%

“…In order to describe pulse characteristics due to particle motion, electrical field, and flow field, all governing equations need to be coupled together during computation. Both particle and channel wall are assumed nonconducting and rigid .…”

Section: Methodsmentioning

confidence: 99%

3D numerical simulation of a Coulter counter array with analysis of electrokinetic forces

et al. 2012

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“…(D) Equipotential contours plotted over the electric field strength around a particle moving through a bent cylindrical pore (left panel); The effect of initial position on particle trajectories where the solid lines represent the predictions from the boundary‐element method and the dashed lines represent the results from the point‐dipole method (right panel). Adapted with permission from House and Luo , © 2011 Wiley‐VCH.…”

Section: Curved Microchannelsmentioning

confidence: 99%

“…C). House and Luo applied a numerical approach based on the boundary‐element method to solve the coupled electric field, fluid flow, and particle motion in particle electrophoresis through a bent cylindrical pore. Their method can handle much closer particle–wall distances than the other numerical approaches such as the finite element method.…”

Section: Curved Microchannelsmentioning

confidence: 99%

Recent advances in direct current electrokinetic manipulation of particles for microfluidic applications

Xuan

2019

Electrophoresis

101

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Microfluidic devices have been extensively used to achieve precise transport and placement of a variety of particles for numerous applications. A range of force fields have thus far been demonstrated to control the motion of particles in microchannels. Among them, electric field‐driven particle manipulation may be the most popular and versatile technique because of its general applicability and adaptability as well as the ease of operation and integration into lab‐on‐a‐chip systems. This article is aimed to review the recent advances in direct current (DC) (and as well DC‐biased alternating current) electrokinetic manipulation of particles for microfluidic applications. The electric voltages are applied through electrodes that are positioned into the distant channel‐end reservoirs for a concurrent transport of the suspending fluid and manipulation of the suspended particles. The focus of this review is upon the cross‐stream nonlinear electrokinetic motions of particles in the linear electroosmotic flow of fluids, which enable the diverse control of particle transport in microchannels via the wall‐induced electrical lift and/or the insulating structure‐induced dielectrophoretic force.

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“…3.44. However, it had been shown that this expression should not be used if the particle is of comparable size to the characteristic length of the electric field and can lead to an inaccurate prediction of the particle trajectories [121]. In this case the dielectrophoretic force F dep on a particle should be calculated with the surface integral over the Maxwell stress tensor T el [160]…”

Section: Non-zero Particle Size -Fem-ale Methods For DC Dielectrophoresismentioning

confidence: 99%

Coordinated Detection of Micro- and Nanoparticles using Tuneable Resistive Pulse Sensing and Optical Spectroscopy

Hauer¹

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<p>The detection and characterisation of micro- and nanoscale particles has become increasingly important in many scientific fields, spanning from colloidal science to biomedical applications. Resistive Pulse Sensing (RPS) and its derivative Tuneable Resistive Pulse Sensing (TRPS), which both use the Coulter principle, have proven to be useful tools to detect and analyse particles in solution over a wide range of sizes. While RPS uses a fixed size pore, TRPS uses a dynamically stretchable pore in a polyurethane membrane, which has the advantages that the pore geometry can be tuned to increase the device's sensitivity and range of detection. The technique has been used to accurately determine the size, concentration and charge of many different analytes. However, the information obtained using TRPS does not give any insight into the particle's composition. In an attempt to overcome this, an experimental technique was developed in order to obtain simultaneous, time-resolved, high-resolution optical spectra of particles passing through the pore. Due to the ordered and controllable fashion in which the particles are guided through the sensing region, this approach has an advantage over diffusion based optical techniques. The experimental setup for the coordinated electrical and optical measurements involves many underlying physical phenomena, e.g. microuidics, electrokinetic effects, and Gaussian beam optics. A significant proportion of this work was therefore devoted to the development and the optimisation of the experimental setup by adapting a commercial TRPS device and a spectrometer with an attached microscope. Methods to engineer the spot size of a Gaussian beam to account for the different pore diameters, and the development of algorithms to filter, analyse and coordinate the recorded data are essential to the technique. The results using fluorescently labelled polystyrene particle sets with diameters from 190nm to 2 µm show that matching rates between the electrical and optical measurements of over 90% can repeatedly be achieved. Mixtures of particle species with similar diameters but with different fluorescent labels were used to demonstrate the technique's capability to characterise the analyte on a particle-by-particle basis and extend the information that can be obtained by TRPS alone. It was also shown that the data acquired with the electrical and optical measurements complement each other and can be used to better understand the TRPS technique itself. The influence of experimental parameters, such as the particle velocity, the beam size and the optical detection volume, on the intensity of the optical signals and the matching rates was studied intensively. These studies showed that the technique requires a careful experimental design to achieve the best results. Overall, the developed technique enhances the particle-by-particle specificity of conventional RPS measurements, and could be useful for a range of particle characterization and bio-analysis applications. Alongside the experiments, semi-analytic modelling and simulations using the Finite Element Method (FEM) were used to understand the particle motion through the pores, to interpret the experimental data, and predict the optical signals. The models were also used to assist the design and the optimization of the experiments. The FEM models were implemented with increasing physical detail and show superior understanding of the TRPS signals compared to the semi-analytic model, which is conventionally used in the TRPS field. The physical phenomena considered included o -axis trajectories, particle-field interactions for both fluid and electric fields, and the non-homogeneous distribution of ions close to the charged membrane and particle interfaces. Several effects which have been observed experimentally could be explained, including the intrinsic pulse height distribution, the current rectification, and the occurrence of bi-phasic pulses, demonstrating the benefits of FEM methods for RPS.</p>

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Effect of direct current dielectrophoresis on the trajectory of a non‐conducting colloidal sphere in a bent pore

Cited by 9 publications

References 37 publications

3D numerical simulation of a Coulter counter array with analysis of electrokinetic forces

3D numerical simulation of a Coulter counter array with analysis of electrokinetic forces

Recent advances in direct current electrokinetic manipulation of particles for microfluidic applications

Coordinated Detection of Micro- and Nanoparticles using Tuneable Resistive Pulse Sensing and Optical Spectroscopy

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