ABSTRACT
Liposomes or lipid vesicles are spherical, self-closed structures composed of curved lipid bilayers, which entrap part of the solvent, in which they freely float, into their interior [1 , 2]. As shown in Fig. 1, they may consist of one or several concentric membranes and hence are referred to as either unilamellar or multilamellar vesicles. Their sizes range from 20 nm for small unilamellar vesicles (SUV) up to several micrometers for large unilamellar vesi cles (LUV) or multilamellar vesicles (MLV). The thickness of a single lipid bilayer mem brane is about 4 nm.