Synthesis And Biological Properties Of Peptided Lipids

A safe and effective carrier plays a key role in gene therapy. Non–viral vectors aregradually replacing viral vectors as they have the advantages such as low toxicity,biocompatibility and easy preparation. They have a promising perspective for application.Two cationic lipids were synthesized in this paper, after separation and purification usingrecrystallization, target lipids with high purity were obtained. All the structures of target lipidswere characterized by ESI-MS, IR,1H NMR and13C NMR. The required purity oftransfection is tested by ESI-MS and HPLC. Cationic liposomes have been made fromcationic lipids through blowing film with N2. The particles were well-distributed in the rangeof50-200nm from transmission electron microscopy.Gel electrophoresis of cationic lipid/DNA complexes was used to assess the relativebinding capability of DNA to liposomes and the following results were obtained. Lipid whichhad a glycine di-peptide showing better binding capability than that had a glycine as the polarhead. With the increase of liposomes/DNA ratio, the binding capability was increased. Thebinding capability of DNA to liposomes has been improved by adding the helper lipid DOPE.The pGFP-N2was used to transfect Hep-2cell in vitro by using the above lipsomes as genecarriers, and they can deliver DNA into cells successfully. The results indicated thattransfection efficiency was higher when the ratios of liposome/DNA were from4/1to6/1.Satisfactory transfection efficiency could be achieved by adding the helper lipid DOPE.This study could be helpful for the design and synthesis of novel cationic lipids.