In vitro evaluation of cationic liposomes prepared with oligopeptide-based lipids for plasmid DNA delivery

Cationic liposomes(CL)were prepared using ditetradecyl N-lysyl-L-glutamate(T₂GL)as cationic lipid and soybean lectithin as helper lipid. Lipoplexes(CL/pDNA)were formed between the CL and plasmid EGFP due to electrostatic interaction. The particle size of CL/pDNA was assayed to be(132. 3±1. 0)nm while Zeta potential was +(31. 35±2. 99)mV. Both CL and CL/pDNA were unilamellar vesicles in terms of morphology. The release of pDNA from CL/pDNA occured when incubated with the appropriate concentration of heparin. When incubated with DNase I, there was no change to CL/pDNA but there existed degradation of pDNA, either naked or bound with Lipofectamine 2000. CL/pDNA was found to possess the highest transfection efficiency(TE)at N/P ratio of 3 and pDNA weight of 4 μg. TE of CL/pDNA was evaluated using 3 kinds of cell lines. In A549 cells, CL/pDNA yielded almost equal TE but much lower cell toxicity if compared with Lipofectamine 2000 reagent. Therefore, it suggested that CL/pDNA be a promising genetic vehicle worth of in vivo evaluation.