Investigation of the Holding Capability of a Single Dielectrophoretic Gate for the Front-End Device of a Bio-Detection System

Abstract

This paper will examine the holding capability of a single dielectric gate. Bennett et al. have previously developed a single dielectrophoretic (DEP) gate for the front-end device of a bio-detection system [12]. By applying a high frequency AC electric field on the top and bottom electrodes, particles which are negatively polarized are repelled from the high field gradient region near the electrodes, and the particles are held in place due to the balancing of the DEP force and the Stokes drag force. However, the particles will flush through the channel if the fluid flow force becomes larger than that the DEP force. Thus, there is a holding capability for the single dielectrophoretic gate which corresponds to the maximum flow rate at which particles can balanced by the DEP force. In this paper, we present a 3D numerical simulation to investigate the parameters that influence the DEP force such as the width of the electrodes, the applied electric field, the ratio of the width of top electrode to the bottom of electrode as well as the horizontal shift between the top electrode and bottom electrode. A select group of parameters is studied in order to achieve the optimal holding capability of the single dielectrophoretic gate. The influence of the phase variation of the AC electric field between the top electrode and bottom electrode is also analyzed.