Abstract: A microfluidic chip based on thin film microelectrode structure was developed for high efficiency cell electrofusion. The top/bottom thin film microelectrode array and the discrete thin film microelectrodes sputtered on the sidewalls of the polymer(Durimide 7510) microchannel constructed the discrete "sandwich" microelectrode structure. As the traditional protruding microelectrodes, this structure could generate nonuniform electric field for dielectrophoresis-based cell alignment/pairing between the microchannel. The cavity between two adjacent microeledctrodes was also filled using the Durimide 7510. It could overcome the shortcoming in the traditional protruding cell-electrofusion chip where many cells could not be aligned and fused in the unfilled cavity. Experimental investigation of cell alignment based on dielectrophoresis and cell electrofusion based on reversible electroporation were conducted using K562 cells and good results were achieved. Low voltage pulses (ca. 10 V) series could produce a strong enough electric field for reversible electroporation. Most cells (ca. 99%) were trapped on the surface of the thin film microelectrodes and almost no cells were docked between two adjacent electrodes on the same sidewall. More than 60% cells were aligned as cell-cell twins and about 40% cells were fused. Thus, compared with traditional cell electrofusion method and protruding microelectrode structures, higher alignment and fusion efficiency were achieved.

Key words: Thinfilm electrode, Cell electrofusion, Microfluidic chip, Alignment, Electroporation