Asymmetric Molecular Friction in Supported Phospholipid Bilayers Revealed by NMR Measurements of Lipid Diffusion

The bilayer−substrate coupling in fluid bilayers of dipalmitoyl phosphatidylcholine (DPPC) on a solid support of spherical silica beads was examined by measuring the lateral diffusion of the lipids in both monolayers using a deuterium NMR relaxation technique. The results obtained at 55 °C show that...

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Bibliographic Details
Published in:Langmuir 1998-03, Vol.14 (5), p.982-984
Main Authors: Hetzer, M, Heinz, S, Grage, S, Bayerl, T. M
Format: Article
Language:English
Subjects:
Chemistry
Exact sciences and technology
General and physical chemistry
Solid-liquid interface
Surface physical chemistry
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Summary:The bilayer−substrate coupling in fluid bilayers of dipalmitoyl phosphatidylcholine (DPPC) on a solid support of spherical silica beads was examined by measuring the lateral diffusion of the lipids in both monolayers using a deuterium NMR relaxation technique. The results obtained at 55 °C show that the lipid diffusion constant in the monolayer facing the silica surface, D = 7.5 × 10-12 m2/s, is slower by a factor of 2 than that in the monolayer exposed to the bulk water (D = 14 × 10-12 m2/s). This indicates that the monolayer−monolayer coupling in fluid bilayers must be rather weak compared to the monolayer−substrate coupling across an ultrathin water film between the bilayer and the silica surface.
ISSN:0743-7463
1520-5827
DOI:10.1021/la9712810