Lipid Nature and Their Influence on Opening of Redox-Active Liposomes

The pathway for contents release from reduction-sensitive liposomes based on a quinone-dioleoylphosphatidylethanolamine lipid conjugate (Q-DOPE) was outlined using results from fluorescent dye contents release assays, as well as single- and multiple-angle light scattering. Experimental observations are consistent with a shape/size change of the reduced liposomes prior to their aggregation, with subsequent near-quantitative contents release achieved only when the lipid membrane experiences conditions favorable to a lamellar to an inverted hexagonal phase transition. Addition of poly(ethyleneglycol)-modified DOPE (PEG-DOPE) to the Q-DOPE liposomal formulation results in stabilization of the lipid bilayer, whereas incorporation of DOPE yields faster contents release. At high DOPE concentrations, DOPE/PEG-DOPE/Q-DOPE liposomes exhibit larger contents release, indicating a change in pathway for contents release. The outcomes here provide a better understanding of the underlying principles of triggered liposomal contents release and the potential utility of specific lipid properties for the rational design of drug delivery systems based on the novel Q-DOPE lipid