Mannosylated liposomes for targeted gene delivery

BACKGROUND Liposomes can be modified with different ligands to control their biological properties, such as longevity, targeting ability, and intracellular penetration, in a desired fashion. The aim of this study was to modify liposomes with a novel mannosylated polyethylene glycol-phosphatidylethanolamine (M-PEG-PE) ligand to achieve active targeted gene delivery. METHODS Rat Kupffer cells were isolated and used as model cells for in vitro evaluation of cytotoxicity and transfection efficiency. The modified liposomes were intravenously injected into the rats, and Kupffer cells were isolated and analyzed by flow cytometry for in vivo gene delivery and expression. RESULTS The M-PEG-PE-modified liposome-enhanced green fluorescence protein plasmid (M-PEG-PE-Lipo-pEGFP) complexes had a particle size of 237 nm and a loading efficiency of 90%. The M-PEG-PE-Lipo-pEGFP complexes displayed remarkably higher transfection efficiency than unmodified Lipo-pEGFP, both in vitro (51%-30%) and in vivo (43%-27%). CONCLUSION M-PEG-PE could function as an excellent active targeting ligand, and M-PEG-PE-modified liposomes could be promising active targeted drug delivery vectors.