ABSTRACT
I. INTRODUCTION Vesicles or liposomes are spherically closed lipid bilayers that enclose an aqueous core and are dispersed in water or an aqueous buffer (see Fig. 1 for a schematic representation). The bilayer is composed of individual lipid molecules, which typically consist of a water-soluble headgroup covalently attached to hydrophobic hydrocarbon chains. Because of this amphiphilic nature, the molecules form aggregates in water in which their hydrophobic tails are shielded as far as possible by the hydrophilic headgroups from the surrounding aqueous environment. Typically, lipid molecules show very low solubility in aqueous media, which-together with their molecular geometryforces them into bilayer aggregates [1].
