Enhancement of transfection efficiency using ligand-modified lipid vesicles

Previously, we had developed a simple gene transfection technique for animal cells using cationic lipid vesicles; a commercially available synthetic cationic surfactant, dimethyldioctadecyl ammonium bromide (DDAB) was used for making lipid vesicles. In the present study, the lipid vesicles for receptor mediated gene transfer were modified with a ligand such as insulin and galactose residues to realize enhanced transfection efficiency and/or cell-specific gene transfection. The insulin-modified lipid vesicle solution mixed with the plasmid DNA (pCMVβ) was added to COS-7, NIH3T3, Hela or HepG2 cells; the transfection efficiency was increased 3–4-fold in all the cell lines tested. Furthermore, a mixture of the galactose-modified lipid vesicles and plasmid pCMVβ was added to HepG2 or HuH-6 cells expressing asialoglycoprotein receptors, and the transfection efficiency was increased 3–4-fold in these cell lines.