Liposomes modified with polycation used for gene delivery: preparation, characterization and transfection in vitro.

Gene therapy provides great opportunities for treating diseases from genetic disorders, infections and cancer. The development of efficient and safe gene transfer systems could be one of the most important factors for successful gene therapy. In the present study, an amphiphilic compound, polyethylenimine (PEI, MW 800)-cholesterol (PEI 800-Chol), firstly designed to modify the surface of liposomes, was synthesized. Polycation liposomes (PCLs) composed of soybean phospholipids (SPL), cholesterol (Chol) and PEI 800-Chol were prepared using film hydration method. The mean particle size of the PCLs was 133.0 nm and the zeta potential was 50.1+/-2.6 mV. Due to the PEI anchored onto the surface of liposomes, higher buffering capacity of PCLs was observed, indicating the potential for buffering in the acidic pH environment of the endosomes. Compared to Lipofectamine 2000, PCLs have equivalent transfection efficiency with significantly low cytotoxicity. Interestingly, the transfection activity of PCLs was not influenced in the presence of serum. Furthermore, we constructed another PCL composed of PEI 800-Chol and DOPE, and transfection efficiency increased notably. In conclusion, the PCLs described in this study have high transfection efficiency with low cytotoxicity, as well as the protection ability from serum, which suggests PCLs would be a potential non-viral gene delivery system.