Targeted delivery of DNA by liposomes and polymers

Abstract

Cationic quaternary ammonium detergents stabilized the lamellar phase of dioleoylphosphatidylethanolamine (DOPE) to form liposomes. Such cationic liposomes interacted with and delivered DNA to tissue culture cells with high efficiency. Positively charged polymers conjugated with lipids were also active in DNA delivery. The transfection activity of the lipopoly- l-lysine under optimal conditions was approximately 3-fold higher than that of Lipofectin, a commercially available liposome reagent. Moreover, the conjugate was much more resistant to serum neutralizing effect. Specific delivery of DNA to target cells was achieved by using the anionic pH-sensitive immunoliposomes. It was found that both pH-sensitivity and incorporation of antibody on liposome surface were important for the high transfection activity. Both the short- and long-term transformation efficiency had been determined and shown to be more superior to those of traditional calcium phosphate precipitation method. Successful delivery and expression of the exogenous genes mediated by pH-sensitive immunoliposomes had been demonstrated in both tissue cultured cells and in a mouse model.