The role of non-ionic surfactants on cationic lipid mediated gene transfer.

Cationic lipid carriers were made of 1,2-dioleoyl-sn-glycero-3-trimethylammoniumpropane (DOTAP), squalene and different amounts of non-ionic surfactants. Various non-ionic surfactants were selected to elucidate the role of Tween 80 in the cationic lipid mediated gene delivery. They had a similar structure to Tween 80 such as various poly(ethyleneglycol) (PEG) chain lengths and acyl chain with different headgroups. For comparison, lipid carriers were also prepared with 1,2-dioleoyl-sn-glycero-3-trimethylammoniumpropane (DOTAP) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). Addition of non-ionic surfactants decreased the emulsion-DNA interaction and affected the transfection activity depending on the chain length and the content of PEG in the surfactant. Among the surfactants, Tween 80 yielded the best transgene expression without showing toxicity in COS-1 cells. The delivery mechanism of the complex was investigated by measuring the effects of endocytosis inhibitors (chloroquine and wortmannin). The emulsion-DNA complex seems to be taken up by the cells via endocytosis.