EXPERIMENTAL CHARACTERIZATION OF LIPOSOMES STABILIZED BY POLYELECTROLYTES AND MECHANISM OF INTERACTION INVOLVED

This article describes the results obtained on stabilization of lipid vesicles with polyelectrolytes. It is shown that the adsorption of chitosan and hyaluronan at different molecular weights stabilizes the vesicles against pH, osmotic, and salt shocks. The amount of adsorbed polymer depends on the molecular weight for hyaluronan but not for chitosan, allowing the conclusion that chitosan adsorbs flat on the surface while hyaluronan forms loops and trains. The maximum amount of polymer adsorbed on the external membrane surface of vesicles corresponds to a low degree of coverage and is interpreted within the frame of a "patch-like" model. Whatever the conditions, all the interactions are concluded to be mainly of an electrostatic nature.