Preparation and experimental study on dielectrophoresis-based microfluidic chip for cell patterning

A dielectrophoresis (DEP)-based microfluidic chip for cell patterning was designed and fabricated to achieve non-contact and batch manipulation of cells. The microfluidic chip employed a polydimethylsiloxane (PDMS) microchannel and two indium tin oxide (ITO) electrodes which were designed as a "step" structure. The distribution of the electric field caused by the microelectrodes was simulated by finite element simulation software COMSOL. The position of the maximum intensity of the electric field was also determined. The ITO microelectrodes and PDMS microchannel were fabricated using the micro-electro-mechanical system (MEMS) technique. After oxygen plasma surface treatment, the PDMS microchannel and glass substrate with the ITO microelectrodes were aligned and bonded to form the experimental microfluidic chip. Through DEP experiments with varying frequencies, the DEP behavior of yeast cells was examined, and the electric field frequency of both positive and negative DEP responses were determined. The results showed that yeast cells with solution conductivity of 60 μS cm^-1 exhibited negative DEP movement in a frequency range of 1-10 kHz, positive DEP movement from 100 kHz to 10 MHz, and no DEP movement at 50 kHz. Under a sinusoidal potential of 8V_p-p with frequency of 5 MHz, the yeast cells were aligned into chains along the "step" edge of microelectrodes.