Supported bilayers: combined specular and diffuse x-ray scattering

TL;DR

This paper introduces a novel combined analysis method for specular and diffuse X-ray scattering to accurately characterize supported lipid bilayers, accounting for thermal fluctuations and substrate roughness, enabling detailed structural insights.

Contribution

The paper presents a new method that simultaneously analyzes specular and off-specular X-ray reflectivity to determine supported bilayer properties with high precision.

Findings

Accurately determines bilayer structure, tension, and rigidity.

Allows investigation of protrusion modes and complex systems.

Enables analysis of lipid, cholesterol, and peptide interactions.

Abstract

A new 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 protusion modes of adsorbed bilayers and opens the way to the investigation of more complex systems including different kinds of lipids, cholesterol or peptides.