Micro orifice based cell pairing and fusion on microfluidic chip

Micro orifice assisted cell fusion assures high-yield fusion without compromising the cell viability. This paper examines feasibility of a cell pairing method compatible with micro orifice based cell fusion to create large number of viable fusants for studying post-fusion cell behavior. We fabricated a microfluidic chip which contained a chamber and a partition. The partition divided the chamber into two compartments and it had a number of embedded micro orifices. The voltage applied to the electrodes located at each compartment generated electric field distribution concentrating in each micro orifice. Cells introduced into each compartment moved towards micro orifice by manipulation of hydrostatic pressure. Dielectrophoretic force trapped the cells in micro orifice and established cell to cell contact through orifice. By applying a pulse, cell fusion was initiated to form a neck between cells. The neck passing through orifice resulted in immobilization of the fused cell pair. Unfused cells washed away. Then, the chip was loaded to a microscope stage incubator for time lapse imaging of the immobilized fusants. The viable fusants were successfully generated by fusion of mouse fibroblast cells. Time lapse observation of the five fusants showed that fused cell pairs were released from micro orifice and became one body. Fusants which reached to cell division phase divided into three daughter cells. We conclude that the presented method of cell pairing and fusion is suitable for high-yield generation of viable fusants and studying of post-fusion phenomena.