Molecular motions in lipid bilayers studied by the neutron backscattering technique

TL;DR

This study uses neutron backscattering to explore slow molecular motions in lipid bilayers, revealing freezing transitions of lipid acyl-chains and hydration water, providing insights into membrane dynamics at nanosecond scales.

Contribution

It demonstrates the application of high-resolution neutron backscattering to distinguish molecular mobility in lipid bilayers and hydration water, offering a new experimental approach.

Findings

Freezing of lipid acyl-chains observed

Second freezing transition identified in hydration water

Technique provides detailed insights into membrane dynamics

Abstract

We report a high energy-resolution neutron backscattering study to investigate slow motions on nanosecond time scales in highly oriented solid supported phospholipid bilayers of the model system DMPC -d54 (deuterated 1,2-dimyristoyl-sn-glycero-3-phoshatidylcholine), hydrated with heavy water. This technique allows to discriminate the onset of mobility at different length scales for the different molecular components, as e.g.\@ the lipid acyl-chains and the hydration water in between the membrane stacks, respectively, and provides a benchmark test regarding the feasibility of neutron backscattering investigations on these sample systems. We discuss freezing of the lipid acyl-chains, as observed by this technique, and observe a second freezing transition which we attribute to the hydration water.