Supported bilayers: Combined specular and diffuse X-ray scattering

L. Malaquin^1,2, T. Charitat¹ and J. Daillant²

¹ Institut Charles Sadron, Université de Strasbourg, CNRS UPR 22, 23 Rue du Loess, BP 84047, 67034, Strasbourg cedex 2, France
² UMR CEA/CNRS SIS2M LIONS, CEA-Saclay, bât. 125, F-91191, Gif-sur-Yvette Cedex, France

Corresponding author: jean.daillant@cea.fr

Received: 7 October 2009
Published online: 19 March 2010

Abstract

A method is proposed for the analysis of specular and off-specular reflectivity from supported lipid bilayers. Both thermal fluctuations and the “static” roughness induced by the substrate are carefully taken into account. Examples from supported bilayers and more complex systems comprising a bilayer adsorbed or grafted on the substrate and another “floating” bilayer are given. The combined analysis of specular and off-specular reflectivity allows the precise determination of the structure of adsorbed and floating bilayers, their tension, bending rigidity and interaction potentials. We show that this new method gives a unique opportunity to investigate phenomena like protrusion modes of adsorbed bilayers and opens the way to the investigation of more complex systems including different kinds of lipids, cholesterol or peptides.