Lecithin-based cationic nanoparticles as a potential DNA delivery system.

Previously, we have reported a novel nanoparticle-based DNA vaccine delivery system, which elicited strong immune responses against antigens of interest encoded by the DNA. The nanoparticles were engineered by cooling pre-formed warm microemulsions comprised of emulsifying wax as the oil phase and hexadecyltrimethyl ammonium bromide (CTAB) as the surfactant. However, the poor aqueous stability of the nanoparticles and the emulsifying wax in the nanoparticles may severely limit the applications of the nanoparticles. In the present study, we used lecithin, a more biocompatible material, instead of emulsifying wax, to prepared lecithin-based cationic nanoparticles. The 50% growth inhibition concentration (IC(50)) of the lecithin-based nanoparticles was found to be more than 1,000-fold higher than that of the emulsifying wax-based nanoparticles. Moreover, the stability of the lecithin nanoparticles was also significantly increased. The size of the nanoparticles did not significantly change during a 6-month storage period at room temperature. Finally, when plasmid DNA was adsorbed on their surface, the lecithin nanoparticles successfully transfected cells in culture. These lecithin-based nanoparticles may hold great potentials as a DNA (vaccine) delivery system.