An equivalent electric circuit as a tool for monitoring micron sized-particles in suspension from electrical impedance measurements

Abstract

Abstract In this work, a microfluidic device with a three-electrode system is used to measure the electrical impedance spectrum of micron-sized particles suspended in Phosphate Buffered Saline (PBS). We use polymer particles of 15 μm and 48 μm of diameter, as they can mimic biological cells in suspension. The main purpose is to study the influence of the particle concentration on impedance parameters and to establish the basis for biological cell suspensions assays. An electric equivalent circuit model is used to describe the experimental impedance data. Results show a high dependence of electrical parameters with the mass fraction and particle size. The model considers the resistance of the bulk solution and the electrical double layer, as the two essential electrical elements. Results show a maximum error of 3% by fitting the measurements to the proposed model. This proposal could be of interest for cytotoxicity assays.