REVERSIBLY POLYMERIZED LIPOSOMES.

Phospholipid bilayer vesicles are of considerable current interest as models for biomembranes, as carriers of drugs, and as devices for photochemical solar energy conversion. In this paper we describe two unique classes of synthetic vesicles which can be transformed into a polymerized state via oxidation and macrocyclic ring opening, respectively. These membranes are based on the thiol-bearing olecules,1,2-bis(11-mercaptoundecanoyl)-sn-glycero-3-phosphocholine, 1,2-bis(16-mercaptohexadecanoyl)-sn-glycero-3-phosphocholine, 1,2-bis(2-mercaptohexadecanoyl)-sn-glycero-3-phosphocholine, as well as a macrocyclic disulfide derivative of the first of these. Two key features of these assemblies, which distinguish them from other forms of polymerized phospholipid vesicles, are that they can be depolymerized via mild chemical reduction and that they are potentially biodegradable.