Permeability Characteristics of Polymeric Bilayer Membranes from Methacryloyl and Butadiene Lipids

Article abstract of DOI:10.1021/ja00318a013

Four polymerizable lipids were synthesized and used for the formation of synthetic bilayer membranes (vesicles).Two of the lipids were methacryloyl ammonium lipids, one with a methacrylamide at the hydrophilic head group of the lipid (α-MA) and one with a methacrylate group at the hydrophobic tail of the lipid (ω-MA).Thermally initiated polymerization of the monomeric bilayer vesicles gave polymers with retention of vesicles structure.The size distribution of the aqueous suspension was not altered significantly on polymerization, and the membranes continued to entrap <3H>glucose.The permeability of poly(α-MA) and poly(ω-MA) membranes is about half that of the unpolymerized bilayers.Previously we reported that about 500 monomer units were found per average polymer chain of poly(α-MA) and poly(ω-MA), which shows that there are several (20 to 100) polymer chains per vesicle (Dorn, K. et al.Makromol.Chem., Rapid Commun. 1983, 4, 513).Two butadiene lipids, one based on a phosphatidylcholine (PC) structure, and one with a taurine head group, also formed bilayer membranes, which could be photopolymerized by exposure to ultraviolet light.These lipids have a sorbate unit (λ_max 257 nm) in each of the two hydrocarbon chains, which allows the photopolymerization to proceed with the formation of cross-links.Poly(butadiene PC) membranes effectively entrapped <3H>glucose for at least a week and were not disrupted by the use of the surfactant Triton X-100.