Mechanisms of cell transfection by electroporation: Field induced DNA uptake and transfection efficiency

DNA transfection of cells by electroporation is simple and the transformant yield is often much higher than that using other chemical or physical methods. E. coli (prokaryotic), NIH 3T3 and HeLa cells (eukaryotic) have been used to study electrotransfection mechanisms. In all cases, transfection followed three essential steps: 1) cation facilitated binding of DNA to the cell surface, 2) electrophoresis of the surface bound DNA into the cells, and 3) the integration and/or expression of the loaded DNA. The first and second steps do not depend on the topology and the molecular weight of DNA, while the third step depends strongly on the topology of the loaded DNA. Transfer of the surface bound DNA into cells depends solely on the electric parameter. However, transfection efficiency depends also on the stability of the foreign DNA in the cytoplasm.