Dehydration-rehydration vesicles (DRVs) were prepared using a modified protocol from Kirby and Gregoriadis as described by Mugabe et al. . Empty liposomes were prepared as described under Section 2.2 with slight modifications. Liposomes were prepared by the thin-film method, where DPPC: DSPC (8:2 molar ratio) with 5% of DSPE-PEG (w/w) were dissolved in ethanol. A thin film was created by removal of ethanol. The lipidic film was rehydrated to a concentration of 6.25 mg/mL with 20 mM Tris buffer (pH 7.0). Small, monodispersed, liposomes were obtained by sequential extrusion through polycarbonate membranes as described under Section 2.2.