Fabrication and characterization of single-supported bilayer membranes of anionic lipids.

POSTER

Abstract

We report the fabrication of bilayer membranes of the anionic lipid DMPG (1,2-dimyristoyl-\textit{sn-}glycero3-phosphoglycerol) deposited on a silicon substrate. Due to electrostatic effects associated with the DMPG molecule, traditional vesicle fusion methods for producing supported bilayers must be modified to encourage rupture. In particular, high divalent salt concentrations in the buffer solution are necessary to ``prime'' the substrate for vesicle adsorption; furthermore, lower DMPG concentrations are required than for the neutral analogue DMPC (1,2-dimyristoyl-\textit{sn-}glycero3-phosphocholine). We speculate that lower DMPG concentrations allow neutralization of the bilayer with hydrogen ions, increasing the membrane fluidity. We also investigated the temperature dependence of the bilayer thickness in order to monitor the gel-to-fluid phase transition of the DMPG and DMPC membranes. Both show a higher transition temperature than found for spherical vesicles. However, the effect is greater for the DMPG bilayer for which the phase transition is shifted to 70 $^{\circ}$C, 45 $^{\circ}$C above the free-vesicle value.

Authors

  • Andrew Miskowiec

    University of Missouri - Columbia

  • Mark Neubauer

    University of Missouri-Columbia, Southern Illinois University Carbondale, Indiana University, Purdue University, Argonne National Laboratory, University of Missouri, College of Physics Science, Qingda University, Qingdao, 266071, China, Indian Institute of Science, Bangalore, India, University of Massachusetts Amherst, Iowa State University, Technical University of Denmark, University of Missouri - Columbia, University of California - San Diego, La Jolla, CA 92093, Department of Physics, University of Missouri-Columbia, Columbia, Missouri 65211, Department of Physics and Astronomy, University of Missouri-Columbia, University of Missouri, Columbia, MO, Department of Physics and Department of Biochemistry, University of Missouri, Columbia, MO 65211, Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, Univ of Missouri - Columbia, Duke University, Shanghai Jiaotong University, Ames Laboratory, U.S. DOE, Texas Center of Superconductivity and the Department of Physics, University of Houston, Institute of Physics, Siberian Division, Russian Academy of Sciences, Krasnoyarsk, 66036, Russia, Oak Ridge National Laboratory, NIST Center for Neutron Research, MU Research Reactor, Ames Laboratory and Dep. of Physics and Astronomy, Iowa State University, AmesAmes Laboratory and Dep. of Physics and Astronomy, Iowa State University, HFIR, Oak Ridge National Laboratory, University of Illinois at Urbana-Champaign

  • Haskell Taub

    University of Missouri - Columbia

  • Mark Neubauer

    University of Missouri-Columbia, Southern Illinois University Carbondale, Indiana University, Purdue University, Argonne National Laboratory, University of Missouri, College of Physics Science, Qingda University, Qingdao, 266071, China, Indian Institute of Science, Bangalore, India, University of Massachusetts Amherst, Iowa State University, Technical University of Denmark, University of Missouri - Columbia, University of California - San Diego, La Jolla, CA 92093, Department of Physics, University of Missouri-Columbia, Columbia, Missouri 65211, Department of Physics and Astronomy, University of Missouri-Columbia, University of Missouri, Columbia, MO, Department of Physics and Department of Biochemistry, University of Missouri, Columbia, MO 65211, Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, Univ of Missouri - Columbia, Duke University, Shanghai Jiaotong University, Ames Laboratory, U.S. DOE, Texas Center of Superconductivity and the Department of Physics, University of Houston, Institute of Physics, Siberian Division, Russian Academy of Sciences, Krasnoyarsk, 66036, Russia, Oak Ridge National Laboratory, NIST Center for Neutron Research, MU Research Reactor, Ames Laboratory and Dep. of Physics and Astronomy, Iowa State University, AmesAmes Laboratory and Dep. of Physics and Astronomy, Iowa State University, HFIR, Oak Ridge National Laboratory, University of Illinois at Urbana-Champaign