Electric pulse-mediated gene transfer in mammalian cells grown in suspension culture

A high-voltage generating machine which could generate semi-rectangular pulses in PBS solution was constructed, and the effects of field strength and duration of the pulse on electric pulse-mediated transformation of mouse mammary carcinoma FM3A cells by a linear form of plasmid pSV2neo DNAs were examined. In parallel, cell survival and growth after pulsing were analyzed. When the field strength and duration of the pulse were increased, the transformation frequency increased, although the cell survival rate decreased. Under the best conditions, the transformation frequency was 2 X 10(-4), which was 80 times higher than that obtained by the calcium phosphate coprecipitation method.