SURFACTANT-MEDIATED GENE-TRANSFER FOR ANIMAL-CELLS

A commercially available cationic surfactant, dimethyl-dioctadecyl amm onium bromide (DDAB), was used for making lipid vesicles. DDAB easily dissolved in water at 60 degrees C and formed lipid vesicles at room t emperature. The Lipid vesicles showed very low cytotoxicity compared w ith other cationic surfactants. After the lipid vesicles were mixed wi th plasmid DNA solution, the solution was added to mammalian cells. Th e addition of a nonionic surfactant (Tween 80) to the cationic lipid v esicles at the weight ratio of 1:1 enhanced transfection efficiency. A dding more or less than the optimal amounts of DNA and lipid vesicles resulted in decreased transfection efficiency. With the optimal amount s of DNA (pCMV beta) and lipid vesicles, about 90-95% of CHO-K1 and BH K-21C13 cells transiently expressed beta-galactosidase activity 24 h a fter transfection. By this procedure, stable transformants around 10(5 ) cells corresponding to 10% efficiency could be obtained by one batch transfection.