Charge-mediated topical delivery of plasmid DNA with cationic lipid nanoparticles to the skin

Cationic lipid nanoparticles (cLNs) were modified to develop a gene delivery system for topical use via a dermal route. The cLNs were formulated using high pressure homogenization method and were composed of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), dioleoylphosphatidylethanolamine (DOPE), Tween 20, and tricaprin as a solid core (1:1:1:1.67, w/w). The prepared cLNs were nanoscale-sized (<100 nm) and were highly positive (51 mV). The cLN/DNA complexes demonstrated enhanced transfection potential in the cells at the optimal ratio without cytotoxic effects. To evaluate its efficacy in topical application, in vitro skin transfer of the cLN/DNA complexes was monitored using the measurement of the surface zeta potential of hairless mouse skin and validated using confocal microscopy of the sectioned skin. The in vivo delivery of plasmid DNA with the cLN formulation was examined using the relative expression levels of mRNA after non-invasive application with the cLN/DNA complexes on hair-removed dorsal skin of mice. The cLNs successfully transferred plasmid DNA to the skin, which was facilitated by the charge-mediated interaction between the cLN/DNA complexes and the skin. These results suggest the promising potential of cLNs as a topical gene delivery system for gene vaccine delivery and cutaneous gene therapy in preclinical and clinical applications.