THE SURFACE-PROPERTIES OF PHOSPHOLIPID LIPOSOME SYSTEMS AND THEIR CHARACTERIZATION

The field of liposome (vesicle) research has expanded considerably ove r the last 30 years. In physical chemical terms liposomes have many of the characteristics of colloidal particles and their stability is det ermined in part by the classical surface forces. It is now possible to engineer a wide range of liposomes varying in size, phospholipid comp osition and surface characteristics. The surfaces of liposomes can be modified by the choice of bilayer lipid as well as by the incorporatio n and covalent linkage of proteins (e.g. antibodies and sugar binding proteins [lectins]), glycoproteins and synthetic polymers. Much of the impetus for liposome design has come from their potential value as dr ug delivery systems. The development of technologies for the productio n of such a range of liposome systems has presented interesting proble ms in the characterisation of their properties. The review addresses t he progress that has been made in characterising the surfaces of diffe rent types of liposomes with specific reference to their electrophoret ic properties and their interpretation and the physical interactions b etween liposomal bilayers.