title: Structure and properties of tethered bilayer lipid membranes with unsaturated anchor molecules.
abstract: The self-assembled monolayers (SAMs) of new lipidic anchor molecule HC18 [Z-20-(Z-octadec-9-enyloxy)-3,6,9,12,15,18,22-heptaoxatetracont-31-ene-1-thiol] and mixed HC18/β-mercaptoethanol (βME) SAMs were studied by spectroscopic ellipsometry, contact angle measurements, reflection-absorption infrared spectroscopy, and electrochemical impedance spectroscopy (EIS) and were evaluated in tethered bilayer lipid membranes (tBLMs). Our data indicate that HC18, containing a double bond in the alkyl segments, forms highly disordered SAMs up to anchor/βME molar fraction ratios of 80/20 and result in tBLMs that exhibit higher lipid diffusion coefficients relative to those of previous anchor compounds with saturated alkyl chains, as determined by fluorescence correlation spectroscopy. EIS data shows the HC18 tBLMs, completed by rapid solvent exchange or vesicle fusion, form more easily than with saturated lipidic anchors, exhibit excellent electrical insulating properties indicating low defect densities, and readily incorporate the pore-forming toxin α-hemolysin. Neutron reflectivity measurements on HC18 tBLMs confirm the formation of complete tBLMs, even at low tether compositions and high ionic lipid compositions. Our data indicate that HC18 results in tBLMs with improved physical properties for the incorporation of integral membrane proteins (IMPs) and that 80% HC18 tBLMs appear to be optimal for practical applications such as biosensors where high electrical insulation and IMP/peptide reconstitution are imperative.
authors.affiliation: Institute of Biochemistry, Vilnius University, Vilnius LT-08662, Lithuania.
authors.forename: Rima
authors.initials: R
authors.lastname: Budvytyte
authors.forename: Gintaras
authors.initials: G
authors.lastname: Valincius
authors.forename: Gediminas
authors.initials: G
authors.lastname: Niaura
authors.forename: Vladislava
authors.initials: V
authors.lastname: Voiciuk
authors.forename: Mindaugas
authors.initials: M
authors.lastname: Mickevicius
authors.forename: Hilary
authors.initials: H
authors.lastname: Chapman
authors.forename: Haw-Zan
authors.initials: HZ
authors.lastname: Goh
authors.forename: Prabhanshu
authors.initials: P
authors.lastname: Shekhar
authors.forename: Frank
authors.initials: F
authors.lastname: Heinrich
authors.forename: Siddharth
authors.initials: S
authors.lastname: Shenoy
authors.forename: Mathias
authors.initials: M
authors.lastname: Lösche
authors.forename: David J
authors.initials: DJ
authors.lastname: Vanderah
mesh_terms: D008051:Lipid Bilayers / Q000737:chemistry*; D008055:Lipids / Q000138:chemical synthesis / Q000737:chemistry*; D008623:Mercaptoethanol / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure
chemical_list: D008051:Lipid Bilayers; D008055:Lipids; C586118:Z-20-(Z-octadec-9-enyloxy)-6,9,12,15,18,22-heptaoxatetracont-31-ene-1-thiol; D008623:Mercaptoethanol