Fig. 4.

HF determination in cationic liposomes. MC₅₄₀ stock concentration was approximately 0.5 mg/ml. The probe was added to a final lipid concentration of 0.1 mg/ml. The lipid/probe ratio was maintained at 160:1, and the sample was allowed to equilibrate for 10 min at a selected temperature (20°C to 60°C). The A₅₇₀/A₅₀₀ ratio (HF) was determined for liposomes (squares), liposomes mixed with DNA, 100:1 lipid/DNA mass ratio (circles), and DNA without liposomes (triangles). Lipid/MC₅₄₀ molar ratio was 160:1, and lipid/DNA mass ratio was 100:1. Results are expressed as the mean of five experiments ± SD