Liposome-linear polyethyleneimine (PEI)-DNA nanocomplexes have shown to be effective non-viral gene delivery vectors. In the present study, we tried to improve the transfection efficiency of these nanocomplexes by liposome modification. For this purpose, the lipopolymer was prepared by the conjugation of hexylacrylate to the PEI. Liposomes comprising lipopolymer and DOTAP (1.2-DiOleoyl-3-Trimethyl Ammonium-Propane) were prepared and extruded through polycarbonate filters to obtain the desired size. The 2.5, 25 and 250 KDa molecular weights of linear PEI have been used in order to prepare modified liposome-PEI-DNA nanocomplexes. Three C/P ratios of each nancomplex were premixed. Size, zeta potential and the DNA condensation ability of these complexes were determined separately, and in the end, the transfection efficiency and cell cytotoxicity of prepared vectors were evaluated on Neuro2A cell line. Mean particle size of all of these nanocomplexes was lower than 220 nm with surface charge of 17.5 to 25.9 mV. The lipopolyplexes (comprising modified liposome:PEI:DNA), modified liposome (as lipoplex) and PEI 250KDa (as polyplex) showed the highest transfection efficacy. This activity was amplified by increase carrier to plasmid (C/P) ratio. In addition, the metabolic activity of prepared vectors was 80-100% for control group. In conclusion, the prepared lipopolyplexes showed high ability to enhance gene transfer.
Keywords: Gene delivery, Liposomes, Lipopolyplexes, Non-viral vector, Polyethyleneimine, Transfection efficiency.