Research Of Novel Cationic Gene Vector Based On Carbamate Bond

Gene therapy has become one of the most important research areas in the medical circle in recent years, its efficiency has been verified in clinical study. Gene vector with high efficiency and low toxicity has been a key factor constrains the development of gene therapy. The cytotoxicity of virus vectors restricts their wide application. Compared to virus vectors, non-viral vectors have lower transfection efficiency, but they have many advantages such as low toxicity, low immune response, unlimited size of nucleic acids that can be delivered, preparation easily and so on. The research of non-viral gene vector with high efficiency and low toxicity has been hotspot of gene therapy.Based on the preliminary work of our research group, a kind of novel cationic lipid with carbamate bond and hydroxyethyl has been designed and synthesized (the length of carbon chain were 12 and 14). All of the products have been characterized by 1H NMR and MS, their purity can meet the requirement of transfection.The values of critical micelle concentration (cmc), Hydrophile-Lipophile Balance number (HLB), Critical array parameters (P) of cationic lipids were gained by experiments or theory calculations. The same type of cationic lipids whose carbon chains were 12 had smallerγcmc and cmc, bigger HLB. Cationic lipo3～6 were prepared using the cationic lipid and the liposome states were studied by TEM and Nano Particle Size and Potential Analyzer.Using the cationic lipo3～6 and lipo1～2 which were prepared by preliminary work as gene vectors, plasmid DNA pGFP-N2 were transfected into cell line Hela and Hepal-6. According to the results under the same condition, for Hela cells, lipo3 has higher transfection efficiency than lipo5; for Hepal-6 cells, lipo3 has higher transfection efficiency than lipo5, lipo1 has higher transfection efficiency than lipo2. It showed that the same type of cationic liposomes whose carbon chains were 12 had higher transfection efficiency than that whose carbon chains were 14. In the experimental range, the same type of cationic liposomes which has smallerγcmc and cmc showed higher transfection efficiency.Compared to commercial gene vector Lipofectamine2000, the cationic liposomes we prepared has higher efficiency and lower toxicity. Compared to lipo1-2, the modified cationic liposomes showed higher efficiency. According to the results under the same condition, for Hela cells, lipo3 and lipo4 has higher transfection efficiency than lipol; for Hepal-6 cells, lipo3 and lipo4 has higher transfection efficiency than lipo1, lipo5 has higher transfection efficiency than lipo2. It showed that the liposomes with hydroxyethyl head group had higher transfection efficiency, which achieved the purpose of designing of cationic lipid molecules.The synthesis of liver targeting cationic lipid with galactose ligand were researched preliminarily in this paper, a series of scheme were designed, which provides some references to the subsequent research.