Dielectrophoretic assessment of microparticle dielectric properties employing a planar carbon electrode platform

Abstract

Carbon-Electrode Dielectrophoresis (CarbonDEP) is a novel variation of the conventional electrode-based DEP. The use of carbon, instead of metal, offers advantages like a wider electrochemical stability window, excellent biocompatibility, and great mechanical properties. In order to optimize the performance of electrokinetic experiments, such as separation and concentration of microparticles, it is necessary to know the dielectric properties of the particle of interest a priori. For the extraction of dielectric properties using DEP, it is required that other electrokinetic phenomena, such as electroosmotic flow (EOF) and electrophoresis (EP), are not present on the experiment. Presented in this work is the implementation of a dielectric properties characterization platform based on CarbonDEP. A microdevice containing planar carbon electrodes was employed to manipulate carboxylated polystyrene particles with diameters of 1 μm and 2.28 μm. Particle responses were obtained by varying the magnitude and frequency of the applied AC potential. Velocity induced on the particles was measured experimentally and electric parameters of the microchannel were obtained through simulations in COMSOL Multiphysics. With this information, a system of non linear equations was built, from which the dielectric properties can be extracted. Potential applications of this work include, but are not limited to, environmental screening for water contamination, food safety, clinical analyses, and improvement of clean energy production methods. The results of this work have great potential to be used as guidelines for the further design and operation of CarbonDEP based systems.