title: Characterization of solid-supported dipalmitoylphosphatidylcholine membranes containing cholesterol.
abstract: The incorporation of cholesterol into dipalmitoylphosphatidylcholine (DPPC) membranes, even in small amounts, has been shown to significantly alter the properties of the membrane. In this work, force-distance interaction profiles of DPPC membranes containing 8 mol % cholesterol obtained using the surface force apparatus are analyzed in the context of high-resolution structural characterization by atomic force microscopy and neutron reflectometry. The adhesion between the mixed membranes was greater than that for pure DPPC and was variable-depending on the number of defects in the outer membrane leaflets. These defects were only detectable by atomic force microscopy and had an average size of 230 ± 30 nm and 1-5% surface density in the outer leaflet. The adhesion between the membranes monotonically increased as the thickness of the membrane decreased-in direct correlation with the number of defects present (exposed hydrophobic groups) in the membrane contact region. Because of the low diffusion rate of gel-phase membranes, the interaction force profiles were stable and no membrane restructuring was observed.
authors: Department of Chemical Engineering and Materials Science, University of California, Davis , One Shields Avenue, Davis, California 95616, United States.
authors: James
authors: J
authors: Kurniawan
authors: Tonya L
authors: TL
authors: Kuhl
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D002784:Cholesterol / Q000737:chemistry*; D008051:Lipid Bilayers / Q000138:chemical synthesis / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D008051:Lipid Bilayers; D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol