Synthesis Of The Cationic Lipids With Different Hydrophobic Tails And Study On The Gene Delivery

Gene therapy is a new method in cancer therapy.However,the lack of safe and efficient carrier limits its application severely.Cationic liposomes have been deeply investigated because of their handy synthesis,low toxicity.In this paper,cationic lipids HCTA,OCTA and UCTA based on DCTA(C12:0),TCTA(C 14:0)are synthesized to explore the effects on gene delivery.They contain quaternary ammonium salt headgroup,the carbamate-linked linker,the glycerol backbone and different hydrocarbon tails(C16:0,C18:0,C18:1).The liposomes are prepared for gene delivery.After purification,the structures of these lipids are characterized by ESI-MS,IR,1H NMR,13C NMR and HPLC to confirm their structures,we get more than 95%purity product.Cationic liposomes are prepared by the method of thin-film and ultrasonic dispersing with the synthesized cationic lipids containing different hydrophobic tails.Nanoparticle analyzer is used to research their size and zeta-potential.The average particle sizes of these liposomes are from 149 to 336 nm,and zeta potential is between 55 and 68 mV.The electrophoretic gel retardation assay is performed to evaluate DNA binding ability with cationic liposomes bearing different hydrophobic tails.The results show that cationic liposomes and DNA plasmids can form the complexes.Different chain length and unsaturated degree result in different DNA binding capacity of liposomes.The DNA binding abilities of DCTA,TCTA,and UCTA cationic liposomes are better than others.With the increase of liposomes/DNA ratio the DNA binding capability go up.The transfection efficiencies of the cationic liposomes with different hydrophobic tails are evaluated against Hela,Hep-2 and NCI-H460 cells lines.The results indicate that the higher transfection efficiency of liposomes can be obtained at the N/P ratios of 3:1.The lipids bearing C12:0,C14:0 saturated chains or C18:1 unsaturated chain show relatively higher transfection efficiency.DCTA and TCTA show similar transfection efficiency to commercially available gene transfection reagents,Lipofectamine2000,meanwhile transfection efficiency of UCTA is superior to DOTAP.The transfection efficiencies of liposomes are good when lip id/DOPE is 1:1.The cytotoxicity of cationic liposomes with different hydrophobic tails is evaluated using the MTT assay.We evaluate cytotoxicity of liposomes at various N/P ratios,and lipofectamine2000 and DOTAP are used as controls.Cell viabilities of above transfection agents are all about 80%in the Hela and Hep-2 cells.DCTA,TCTA and UCTA showed relatively lower cytotoxicity than HCTA and OCTA.