(482e) Cell Electrofusion Chip Based On Micro-Cavity Microelectrodes

A microfluidic chip with micro-cavity structures is designed and fabricated on a SOI substrate. More than 20,000 pairs of micro-cavity structures are patterned on the vertical sidewall of the serpentine-shaped microchannel. In each micro-cavity, the sidewall parallel to the microchannel serves as microelectrode; while the other two sidewalls, which are perpendicular to the microchannel, are fabricated by SiO₂ insulator. Such design is to focus electric field at the opening of each micro-cavity, where the cell-cell contact point and electrofusion occurs. Concentrated electric field at the contact point improves electrofusion efficiency and reduces the probability of multi-cell electrofusion. In addition, it reduces the imposed voltage for cell electrofusion and improves the viability of the fused cells. NIH3T3 and myoblast cells are used to test the microfluidic device. Under the positive dielectrophoretic force induced by AC signal (Frequency: 1MHz, Vp~p: 2V), almost all cells are captured into the micro-cavity structures and achieve 2-cell pairing with about 60% efficiency. Subsequently, DC electric pulses (9V, 50us) are applied to induce electrofusion. About 50% cells loaded into the microfluidic chip are fused into hybrid cells. Multi-cell electrofusion is not observed in the device. The cell pairing and fusion efficiency are higher than those obtained in traditional electrofusion methods and most existing microfluidic devices.