Improving the Design of Insulator-Based Dielectrophoretic Devices

Dielectrophoresis (DEP) is an electric field driven technique that originates from polarization effects when particles are exposed to non-uniform electric fields. Insulator-based dielectrophoresis (iDEP) employs insulating structures embedded in a microchannel to produce electric field gradients necessary to generate dielectrophoretic forces on particles. This contribution presents a detailed analysis of particle trapping capacity in microchannels with arrays of insulating structures. The effect of the shape, dimensions  and spacing of the insulating structures on the dielectrophoretic trapping were explored. This study includes experimental and mathematical modeling work. COMSOL Multiphysics® was used to determine the distribution of the electric field and electric field gradient within the array of insulating posts in order to determine the optimum set of parameters that maximize the particle trapping capacity of a channel. The phenomena that contribute to particle movement are introduced with an analysis of particle motion with respect to a local electric. Experimentation was performed by applying DC electric potentials across an iDEP microchannel designed with the optimum set of parameters and comparing its performance with commonly used microchannels. All experiments were carried out with devices made from PDMS. The experimental and modeling results clearly depict the dependence of the particle trapping capacity with respect to the considered design parameters. The findings from this study provide a systematic approach towards the design of highly efficient iDEP devices.