title: High coverage fluid-phase floating lipid bilayers supported by ω-thiolipid self-assembled monolayers.
abstract: Large area lipid bilayers, on solid surfaces, are useful in physical studies of biological membranes. It is advantageous to minimize the interactions of these bilayers with the substrate and this can be achieved via the formation of a floating supported bilayer (FSB) upon either a surface bound phospholipid bilayer or monolayer. The FSB's independence is enabled by the continuous water layer (greater than 15 Å) that remains between the two. However, previous FSBs have had limited stability and low density. Here, we demonstrate by surface plasmon resonance and neutron reflectivity, the formation of a complete self-assembled monolayer (SAM) on gold surfaces by a synthetic phosphatidylcholine bearing a thiol group at the end of one fatty acyl chain. Furthermore, a very dense FSB (more than 96%) of saturated phosphatidylcholine can be formed on this SAM by sequential Langmuir-Blodgett and Langmuir-Schaefer procedures. Neutron reflectivity used both isotopic and magnetic contrast to enhance the accuracy of the data fits. This system offers the means to study transmembrane proteins, membrane potential effects (using the gold as an electrode) and even model bacterial outer membranes. Using unsaturated phosphatidylcholines, which have previously failed to form stable FSBs, we achieved a coverage of 73%.
authors.affiliation: ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Harwell OX11 0QX, UK.
authors.forename: Arwel V
authors.initials: AV
authors.lastname: Hughes
authors.affiliation: Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC 2001, New South Wales 2232, Australia.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Holt
authors.affiliation: ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Harwell OX11 0QX, UK Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Daulton
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
authors.forename: Andrei
authors.initials: A
authors.lastname: Soliakov
authors.affiliation: ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Harwell OX11 0QX, UK.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Charlton
authors.affiliation: Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Roser
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne NE2 4HH, UK jeremy.lakey@ncl.ac.uk.
authors.forename: Jeremy H
authors.initials: JH
authors.lastname: Lakey
mesh_terms: D001499:Bayes Theorem; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D008051:Lipid Bilayers; D008055:Lipids / Q000737:chemistry*; D008280:Magnetics; D008564:Membrane Potentials; D010713:Phosphatidylcholines / Q000737:chemistry*; D010743:Phospholipids / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D020349:Surface Plasmon Resonance; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D008051:Lipid Bilayers; D008055:Lipids; D010713:Phosphatidylcholines; D010743:Phospholipids; D013438:Sulfhydryl Compounds; D014867:Water; D006046:Gold
keywords: floating supported bilayer; gold; magnetic contrast; neutron reflection; self-assembled monolayer; thiolipid