Joule heating in electrokinetic flow

Joule heating effects on electroosmotic flow in insulator-based dielectrophoresisInsulator-based dielectrophoresis (iDEP) is an emerging technology that has been successfully used to manipulate a variety of particles in microfluidic devices. However, due to the locally amplified electric field around the in-channel insulator, Joule heating often becomes an unavoidable issue that may disturb the electroosmotic flow and affect the particle motion. This work presents the first experimental study of Joule heating effects on electroosmotic flow in a typical iDEP device, e.g. a constriction microchannel, under DC-biased AC voltages. A numerical model is also developed to simulate the observed flow pattern by solving the coupled electric, energy, and fluid equations in a simplified two-dimensional geometry. It is observed that depending on the magnitude of the DC voltage, a pair of counter-rotating fluid circulations can occur at either the downstream end alone or each end of the channel constriction. Moreover, the pair at the downstream end appears larger in size than that at the upstream end due to DC electroosmotic flow. These fluid circulations, which are reasonably simulated by the numerical model, form as a result of the action of the electric field on Joule heatinginduced fluid inhomogeneities in the constriction region.

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“…We considered the temperature dependence of fluid permittivity, electric conductivity and viscosity using the following expressions [31]:…”

Section: Numerical Methods and Materials Propertiesmentioning

confidence: 99%

“…It has been long known in capillary electrophoresis that Joule heating can elevate the buffer temperature and disturb the electroosmotic flow causing significant sample dispersion [30][31][32][33]. The effects of Joule heating on fluid temperature and motion in eDEP have been investigated previously [34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Joule heating effects on electroosmotic flow in insulator‐based dielectrophoresis

et al. 2011

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“…41 Navier-Stokes equation is applied for an incompressible fluid of low Reynolds number, and the steady fluid flow can be described as below 42 …”

Section: Acet Theorymentioning

confidence: 99%

In-plane microvortices micromixer-based AC electrothermal for testing drug induced death of tumor cells

et al. 2016

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Herein, we first describe a perfusion chip integrated with an AC electrothermal (ACET) micromixer to supply a uniform drug concentration to tumor cells. The inplane fluid microvortices for mixing were generated by six pairs of reconstructed novel ACET asymmetric electrodes. To enhance the mixing efficiency, the novel ACET electrodes with rotating angles of 0 , 30 , and 60 were investigated. The asymmetric electrodes with a rotating angle of 60 exhibited the highest mixing efficiency by both simulated and experimental results. The length of the mixing area is 7 mm, and the mixing efficiency is 89.12% (approximate complete mixing) at a voltage of 3 V and a frequency of 500 kHz. The applicability of our micromixer with electrodes rotating at 60 was demonstrated by the drug (tamoxifen) test of human breast cancer cells (MCF-7) for five days, which implies that our ACET inplane microvortices micromixer has great potential for the application of drug induced rapid death of tumor cells and mixing of biomaterials in organs-on-a-chip systems. Published by AIP Publishing. [http://dx

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“…Therefore, the average temperature elevation in the buffer is estimated to be about 2°C in this experiment. 59 Such Joule heating effects can be mitigated by reducing the channel depth or lowering the buffer concentration. Note that the calculated thermal diffusion time is about 40 s over a 2-mm-thick PDMS slab.…”

Section: Joule Heating Effectsmentioning

confidence: 99%

Integrated electrical concentration and lysis of cells in a microfluidic chip

et al. 2010

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Lysing cells is an important step in the analysis of intracellular contents. Concentrating cells is often required in order to acquire adequate cells for lysis. This work presents an integrated concentration and lysis of mammalian cells in a constriction microchannel using dc-biased ac electric fields. By adjusting the dc component, the electrokinetic cell motion can be precisely controlled, leading to an easy switch between concentration and lysis of red blood cells in the channel constriction. These two operations are also used in conjunction to demonstrate a continuous concentration and separation of leukemia cells from red blood cells in the same microchannel. The observed cell behaviors agree reasonably with the simulation results.

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Joule heating in electrokinetic flow

Cited by 143 publications

References 104 publications

Joule heating effects on electroosmotic flow in insulator‐based dielectrophoresis

Joule heating effects on electroosmotic flow in insulator‐based dielectrophoresis

In-plane microvortices micromixer-based AC electrothermal for testing drug induced death of tumor cells

Integrated electrical concentration and lysis of cells in a microfluidic chip

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