Effect of array and shape of insulating posts on proteins focusing by direct current dielectrophoresis

This paper presents a simulation model of the characteristics of proteins according to the array and shape of the insulating posts based on direct current (DC) dielectrophoresis (DEP). COMSOLA (R)(v4.2a) multiphysics software was used to examine the response of moderately-sized proteins. A simulation model of the protein concentration distribution was developed based on the current conservation equations and a time-dependent concentration-distribution equation. The medium was water, and voltages of 1, 5 and 10 kV DC were applied. The insulating posts were circular and square, and were arrayed in-plane and out-of-plane embedded in a microchannel. Microscale geometries were used to examine the protein concentration distributions in the device. The results showed that the in-plane array is greater than out-of-plane array in efficiency. In addition, the efficiency increased in the order of a square and circle. These results can be explained by the formation of different electric potential streamlines, which depend on the array and shape of the insulating posts. In addition, the protein was found to be more concentrated at both the inlet and outlet of the insulating post arrangement. A simulation revealed that the circular shape with an in-plane arrangement has the best efficiency of protein aggregation under the DEP effect.