Characterization of zwitterionic phosphatidylcholine-based bilayer vesicles as efficient self-assembled virus-like gene carriers.

Entrapment of plasmid DNA (pDNA) in an aqueous compartment separated from the bulk external aqueous medium by a phospholipid bilayer resembles a structure similar to a primitive living cell, and interestingly, this phenomenon occurs completely self-assembled. Being inspired by such a structure as well as using the dehydration-rehydration technique, we were able to encapsulate pDNA without using multivalent cations and with high efficiency (98 %) into noncationic lipid bilayer vesicles. These liposomes which were composed of dimyristoyl-sn-glycero-3-phosphocholine unlike cationic liposomes, were nontoxic. The obtained liposome structure was able protect DNA against nuclease and was completely stable, in a way that even after 6 months, it still kept the pDNA in its structure, and there was a small change in its size (100-150 nm) determined by dynamic light scattering. The purpose of this research is to polarize the researchers' interest toward utilization of neutral liposomes originating from the cell membrane as the most efficient carrier for gene delivery. We indicated that in using such carriers, which are the most similar synthetic structures to viruses, their inability in electrostatic interaction with DNA would not be an obstacle for entrapping nucleic acids.