Comparison of Bipolar and Unipolar Pulses in Cell Electrofusion: Simulation and Experimental Research

Abstract

Unipolar pulses have been used in cell electrofusion over the last decades. However, the problem of high mortality with unipolar pulses has not been solved effectively. The cell fusion rate is restricted by cell mortality. By using the advantages of bipolar pulses which cause less cell damage, this paper attempts to use bipolar pulses to increase the cell fusion rate. the transmembrane voltage and pore density of cells subjected to unipolar/bipolar pulses were simulated in COMSOL software. In an experiment, two 40μs unipolar and two 20-20μs bipolar pulses with electric fields of 2, 2.5, and 3kV/cm were applied to SP2/0 murine myeloma cells. To determine the cell fusion rate and cell mortality, cells were stained with Hoechst 33342 and propidium iodide. the simulation in this paper showed that a high transmembrane voltage and a high pores density were concentrated only at the contact area of cells when bipolar pulses were used. The results of the cell staining experiment verified the simulation analysis. When bipolar pulses were applied, the cell mortality was significantly reduced. In addition, the cell fusion rate with bipolar pulses was almost two times higher than that with unipolar pulses. for cell electrofusion, compared with unipolar pulses, bipolar pulses can not only reduce the cell mortality remarkably but also improve the cell fusion rate obviously. this paper introduces a novel way to increase the fusion rate of cells.