Transfection and structural properties of phytanyl substituted gemini surfactant-based vectors for gene delivery

In this study, the transfection ability and cytotoxicity of a series of phytanyl substituted gemini surfactants, rationally designed and synthesized in an attempt to create cationic surfactants that will improve transfection efficiencies of non-viral vectors was evaluated in OVCAR-3 cells at the charge ratios (N(+)/P(-)) of 2:1, 5:1, and 10:1. Particle sizes, zeta potentials, and small angle X-ray scattering (SAXS) profiles were also determined. For each gemini surfactant complex, the transfection efficiency and cytotoxicity are observed to go through a more or less well-evidenced maximum, occurring at different values of the charge ratio (N(+)/P(-)), depending on the surfactant structure. Considering both results of in vitro transfection efficiency and cytotoxicity, the optimal charge ratio to formulate the complexes containing phy-3-m was found to be 5:1. The particle size decreased, while zeta potential increased with increasing N(+)/P(-). Comparing particle size and zeta potential with transfection efficiency, no correlation between size/zeta potential and transfection ability was observed. Analysis of SAXS profiles indicates that the ability of phy-3-m delivery system to adopt multiple phases correlated well with their higher transfection efficiency in OVCAR-3 cells.