Composites of malonic acid diamides and phospholipids - Structural parameters for optimal transfection efficiency in A549 cells

The aggregation behavior of various zwitterionic helper phospholipids, such as DOPE, DOPC, and DPPC, in combination with two new cationic lipids, namely TH4 and OH4 (second generation of malonic acid diamides) in different molar ratios was studied with regard to their physical-chemical properties. Additionally, lipoplexes prepared from these lipid mixtures were characterized with respect to the transfection efficacy using an EGFP-assay. The lipid mixtures with the fluid cationic lipid OH4 and DOPE have shown comparable transfection efficiency with Lipofectamine 2000 (R). Furthermore, this report demonstrates the huge influence of the helper lipid on the transfection efficiency. Thereby, alkyl chain fluidity, lipid miscibility and charge density have an important influence on an efficient gene transfer.