Dehydration does not affect lipid-based hydration lubrication

Yihui Dong, Nir Kampf, Yaelle Schilt, Wei Cao, Uri Raviv, Jacob Klein*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Phosphatidylcholine (PC) lipid bilayers at surfaces massively reduce sliding friction, via the hydration lubrication mechanism acting at their highly-hydrated phosphocholine headgroups, a central paradigm of biological lubrication, particularly at articular cartilage surfaces where low friction is crucial for joint well-being. Nanotribological measurements probed the effect on such lubrication of dehydration by dimethyl sulfoxide (DMSO), known to strongly dehydrate the phosphocholine headgroups of such PC bilayers, i.e. reduce the thickness of the inter-bilayer water layer, and thus expected to substantially degrade the hydration lubrication. Remarkably, and unexpectedly, we found that the dehydration has little effect on the friction. We used several approaches, including atomic force microscopy, small- and wide-angle X-ray scattering and all-atom molecular dynamics simulations to elucidate this. Our results show that while DMSO clearly removes hydration water from the lipid head-groups, this is offset by both higher areal head-group density and by rigidity-enhancement of the lipid bilayers, both of which act to reduce frictional dissipation. This sheds strong light on the robustness of lipid-based hydration lubrication in biological systems, despite the ubiquitous presence of bio-osmolytes which compete for hydration water.

Original languageAmerican English
Pages (from-to)18241-18252
Number of pages12
JournalNanoscale
Volume14
Issue number48
DOIs
StatePublished - 23 Nov 2022

Bibliographical note

Publisher Copyright:
© 2022 The Royal Society of Chemistry.

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