ELECTROPORATION EFFICIENCY IN MAMMALIAN-CELLS IS INCREASED BY DIMETHYL-SULFOXIDE (DMSO)

Electroporation is one of the most common methods used transform mamma lian cells with plasmids. This method is versatile and can be adapted to meet the requirements of many cell lines. However, sometimes the ef ficiency of this method is low. We demonstrate that dimethyl sulfoxide (DMSO) facilitated a better DNA uptake in four different cell lines ( HL60, TR146, Cos-7 and L132). The cells were electroporated with a bet a-Gal expression plasmid in a medium containing DMSO (1.25%) during, a nd for 24 h after the pulse. In all these cells a dramatic (up to 8-fo ld) increase in transfection efficiency occurred after this treatment. This method opens up the possibility of using electroporation even in cells which are difficult to transfect.