A microfluidic chip integrated with 3D sidewall electrodes and wavy microchannel for cell focusing and separation

Abstract

Cell focusing and separation is a prerequisite for several biological applications. Among these technologies that can achieve the operation, dielectrophoresis (DEP) has been widely used due to its non-contact, label-free and easy-to-operate advantages. In this paper, we designed a microchip that integrates 3D electrodes and wavy microchannel for cell focusing and separation. The 3D electrodes act as not only the electrodes but also as the microchannel walls. The wavy microchannel enables 3D electrodes to generate electric field gradient required by DEP force in the entire microchannel. Cells can be focused and separated under the synergistic effect of DEP and fluidic forces. We have demonstrated the feasibility of the microchip through numerical simulations and experiments. And we validated our approach by demonstrating focusing and separation of A549 and HeLa cells. According to the electrical differences of cells, in the range of 61–99 kHz, the two types of cells can be focused into three streams under the action of positive and negative DEP force to achieve cell separation. With the increase of the voltage amplitude to 10 V, the width of the cell streams was focused to about 30 μm, which can improve the effect of cell separation, the separation efficiency of A549 and HeLa can reach 91.2% and 95.1%, respectively. The proposed microchip is expected to provide a new pathway for designing an effective cell focusing and separation platform.