Authors: M. Foldvari, I. Badea, S. Wettig, R. Verrall and M. Bagonluri
Affilation: University of Saskatchewan, Canada
Pages: 128 - 131
Keywords: gene delivery, cationic surfactant, liposome, nanoemulsion, DNA
Our main goal is to develop micro/nano-scale self-assembling delivery vehicles for cutaneous gene therapy. The objective of this study was to characterize the structural and physicochemical properties of novel dicationic lipid-based DNA complexes by atomic force microscopy (AFM), small-angle x-ray scattering (SAXS), zeta potential and particle size analysis in order to determine the optimum parameters required for cellular transfection and cutaneous transfer. A series of cationic lipid-DNA complexes based on dicationic (gemini) surfactants and other lipids of various compositions were constructed. The transfection efficiency (TE) was found to be dependent on the length of the spacer between the two positively charged head groups, with C3 spacer showing the highest activity. In vivo data indicate that shorter spacer lengths is also important in dermal delivery. Particle size of the complexes and the liposomes were generally in the range of 100-200 nm. The degree of positive charge correlated with TE only for the DNA/gemini complexes, however, in case of DNA/gemini/DOPE (helper lipid) complexes structural formation (a mixture of lamellar and hexagonal phases) was more important. The in vivo efficiency of topical liposomal and nanoemulsion formulations was also dependent on structural characteristics such size and the presence of both lamellar and cubic phases.