Preparation Of Novel Cationic Liposomes For In Vitro Transfection Of Small Interfering RNA

Gene therapy is a new treatment approach for incurable diseases by modifying, or silencing target genes. However, lack of safe and efficient gene carriers limits the clinical application of gene therapy. Therefore, development of safe and efficient gene carriers becomes the key to the clinical application of gene therapy. Non-viral vectors for gene therapy has gained much attention, among which cationic liposomes have been extensively studied.Spermine, which is a small molecue polyamine involved in the metabolism of eukaryotic cells, is a cationic compound with 4 protonable amine atoms. However, efficient gene delivery by spermine is feasible due to its low molecular weight. In this study, 5 derivatives of spermine were synthesized and cationic liposomes were prepared using each one of these derivaties together with cholesterol in a ratio of 1/1(mol/mol). Different contents of ethanol(50%, 25% and 12.5%) used in the preparation process were studied and the optimized ethanol content was 12.5%. Thereafter, cationic liposomes based on compound 1-5 were studied regarding(1) si RNA loading efficiency,(2) cell uptake of the si RNA-loaded cationic liposome,(3) trafection and si RNA release the si RNA-loaded cationic liposome and(4) cytotoxicity of the si RNA-loaded cationic liposome.The overall results have shown that the cationic liposomes based on the 5 derivatives of spermine exhibited comparable si RNA loading efficiency and transfection efficiency, and are therefore potential gene carriers. Key words: spermine, si RNA, liposome, lipospermine...