Comprehensive study of cationic liposomes composed of DC-Chol and cholesterol with different mole ratios for gene transfection

The ability of cationic liposomes composed of DC-Chol and cholesterol to carry pDNA into 293 T cells was investigated. Lipoplexes formed between DC-Chol/cholesterol liposomes and pDNA (encoding green fluorescent protein, GFP) were analyzed in terms of morphology observation, turbidity determination, particle size and zeta potential measurement, differential scanning calorimetry (DSC), gel retardation assay, cytotoxicity analysis in 293 T cells and transfection efficiency. The results showed that liposome preparation at or above 66.7 mol% cholesterol in formulation exhibited a calorimetric transition caused by anhydrous cholesterol domain at about 41 °C. In comparison with the control, DOPE-containing liposomes, DC-Chol/cholesterol carriers showed more stable particle size, lower turbidity, higher activity for transfecting cells in the presence of high concentration serum (50% FBS), primarily due to the neutral domain formation by increasing mole ratios of cholesterol in formulation, as well as relatively lower cytotoxicity. Based on the results, it is suggested that incorporating high contents of cholesterol might be a potentially applicable method for various kinds of cationic lipids to obtain the gene carriers with high capability for in vivo transfection.