Cationic Liposomes Modified with Polyallylamine as a Gene Carrier: Preparation, Characterization and Transfection Efficiency Evaluation

Cationic polymers and cationic liposomes have shown to be effective non-viral gene delivery vectors. In this study, we tried to improve the transfection efficiency by employing the advantages of both. For this purpose, modified polyallylamines (PAAs) were synthesized. These modifications were done through the reaction of PAA (15 KDa) with acrylate and 6-bromoalkanoic acid derivatives. Liposomes comprising of these cationic polymers and cationic lipid were prepared and extruded through polycarbonate filters to obtain desired size. Liposome-DNA nanocomplexes were prepared in three carrier to plasmid (C/P) ratios. Size, zeta potential and DNA condensation ability of each complex were characterized separately and finally transfection efficiency and cytotoxicity of prepared vectors were evaluated in Neuro2A cell line. The results showed that mean particle size of all these nanocomplexes was lower than 266 nm with surface charge of 22.0 to 33.9 mV. Almost the same condensation pattern was observed in all vectors and complete condensation was occurred at C/P ratio of 1.5. The lipoplexes containing modified PAA 15 kDa with 10% hexyl acrylate showed the highest transfection efficacy and lowest cytotoxicity in C/P ratio of 0.5. In some cases nanocomplexes consisting of cationic liposome and modified PAA showed better transfection activity and lower cytotoxicity compared to PAA.