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Diffusion in Single Solid Supported Lipid Bilayers Studied by Quasi-Elastic Neutron Scattering

Published

Author(s)

Clare L. Armstrong, Martin D. Kaye, Michaela Zamponi, E. Mamontov, Madhu Sudan Tyagi, Timothy Jenkins, Maikel C. Rheinstadter

Abstract

It seems to be increasingly accepted that the diversity and composition of lipids play an important role in the function of biological membranes. A prime example of this are lipid rafts; regions enriched with certain types of lipids which are speculated to be relevant to proper functioning of membrane embedded proteins. Although the dynamics of membrane systems have been studied for decades, the microscopic dynamics of lipid molecules, even in simple model systems, is still an active topic of debate. Neutron scattering has proven to be an important tool for accessing the relevant nanometer length scale and nano to picosecond time scales, thus providing complimentary information to macroscopic techniques. Despite their potential relevance for the development of functionalized surfaces and biosensors, the study of single supported membranes using neutron scattering poses the challenge of obtaining relevant dynamic information from a sample with minimal material. Using state of the art neutron instrumentation we were able to model lipid diffusion in single supported lipid bilayers. We find that diffusion is suppressed as compared to diffusion in stacked membranes. More importantly, the molecular mechanism for lipid motion in the single bilayer was found to be a continuous diffusion, rather than the flow-like ballistic motion reported in the stacked membrane system. We observed enhanced diffusion at the nearest neighbour distance of the lipid molecules, which is speculated to be the result of jump diffusion. The suppression and change of character of the diffusion can most likely be attributed the effects of the supporting substrate.
Citation
Soft Matter
Volume
6

Keywords

Lipid bilayers, quasi-elastic, neutron scattering, diffusion of water

Citation

Armstrong, C. , Kaye, M. , Zamponi, M. , Mamontov, E. , Tyagi, M. , Jenkins, T. and Rheinstadter, M. (2010), Diffusion in Single Solid Supported Lipid Bilayers Studied by Quasi-Elastic Neutron Scattering, Soft Matter, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=905826 (Accessed April 14, 2024)
Created September 30, 2010, Updated October 12, 2021