title: Cholesterol/phospholipid interactions in hybrid bilayer membranes.
abstract: The interactions between cholesterol and saturated phospholipids in hybrid bilayer membranes (HBMs) were investigated using the interface-sensitive technique of vibrational sum frequency spectroscopy (VSFS). The unique sensitivity of VSFS to order/disorder transitions of the lipid acyl chains was used to determine the main gel to liquid crystal phase transition temperature, Tm, for HBMs of binary cholesterol/phospholipid mixtures on octadecanethiolate self-assembled monolayers. The phase transition temperature and the breadth of the transition were shown to increase with cholesterol content, and the phase boundaries observed in the cholesterol/phospholipid HBMs were comparable to the published phase diagrams of binary cholesterol/phospholipid vesicles. A thermodynamic assessment of the cooperative units of the HBM phase transitions revealed the presence of <10 nm diameter domains that were independent of the cholesterol composition.
authors.affiliation: The National Institute of Standards and Technology, 100 Bureau Drive, MS8443, Gaithersburg, MD, USA.
authors.forename: Dustin
authors.initials: D
authors.lastname: Levy
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Briggman
mesh_terms: D002784:Cholesterol / Q000737:chemistry*; D006358:Hot Temperature; D008051:Lipid Bilayers / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry; D044367:Phase Transition; D010743:Phospholipids / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D010743:Phospholipids; D002784:Cholesterol