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Structure and fluctuations of a single floating lipid bilayer.

ABSTRACT: A single lipid molecular bilayer of 17 or 18 carbon chain phosphocholines, floating in water near a flat wall, is prepared in the bilayer gel phase and then heated to the fluid phase. Its structure (electron density profile) and height fluctuations are determined by using x-ray reflectivity and non-specular scattering. By fitting the off-specular signal to that calculated for a two-dimensional membrane using a Helfrich Hamiltonian, we determine the three main physical quantities that govern the bilayer height fluctuations: The wall attraction potential is unexpectedly low; the surface tension, roughly independent on chain length and temperature, is moderate (approximately 5 x 10(-4) J.m(-2)) but large enough to dominate the intermediate range of the fluctuation spectrum; and the bending modulus abruptly decreases by an order-of-magnitude from 10(-18) J to 10(-19) J at the bilayer gel-to-fluid transition.

SUBMITTER: Daillant J

PROVIDER: S-EPMC1183447 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature

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Structure and fluctuations of a single floating lipid bilayer.

Daillant J J Bellet-Amalric E E Braslau A A Charitat T T Fragneto G G Graner F F Mora S S Rieutord F F Stidder B B

Proceedings of the National Academy of Sciences of the United States of America 20050808 33

A single lipid molecular bilayer of 17 or 18 carbon chain phosphocholines, floating in water near a flat wall, is prepared in the bilayer gel phase and then heated to the fluid phase. Its structure (electron density profile) and height fluctuations are determined by using x-ray reflectivity and non-specular scattering. By fitting the off-specular signal to that calculated for a two-dimensional membrane using a Helfrich Hamiltonian, we determine the three main physical quantities that govern the ...[more]

PMID: 16087874

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