Partitioning of Ethanol into Lipid Membranes and its Effect on Fluidity and Permeability as seen by X-ray and Neutron Scattering

Published

October 1, 2012

Author(s)

Laura Toppozini, Clare L. Armstrong, Matthew A. Barrett, Songbo Zheng, Lindy Luo, Hirsh Nanda, Victoria Garcia Sakai, Maikel C. Rheinstadter

Abstract

We present a combined neutron and x-ray scattering investigation to study the effect of ethanol on molecular structure and dynamics of lipid membranes. DMPC powder hydrated with a 5wt% ethanol solution (corresponding to 2mol% of ethanol) were used for this study. From high resolution x-ray experiments the position and participation of the ethanol molecules in the phospholipid bilayers was determined in their gel and fluid phase. We find that the ethanol molecules reside in the head group region of the bilayers, with 1.6 ethanol molecules per lipid molecule. We find evidence for enhanced permeability in both fluid and gel phases of the phospholipid bilayers in the presence of ethanol molecules. Elastic and quasi-elastic neutron scattering data, obtained using a neutron backscattering spectrometer, was used to study slow nanosecond molecular dynamics on length scales corresponding to lipid diffusion, acyl chain dynamic and solvent dynamics. While the presence of ethanol molecules had no observable effect on these types of dynamics in the fluid L_aphla} phase, the membranes appeared to have a higher degree of order in gel (L_aphla}) and ripple (P_Pdbeta¿¿) phase. In particular, lipid diffusion was found to be slower by a factor of two in the more rigid gel phase when ethanol was present.

Citation

Soft Matter

Volume

8

Pub Type

Journals

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Keywords

Ethanol, DMPC, lipid membrane, gel phase, lipid diffusion, tail dynamics, membrane structure, backscattering, diffraction

Citation

Toppozini, L. , Armstrong, C. , Barrett, M. , Zheng, S. , Luo, L. , Nanda, H. , Garcia Sakai, V. and Rheinstadter, M. (2012), Partitioning of Ethanol into Lipid Membranes and its Effect on Fluidity and Permeability as seen by X-ray and Neutron Scattering, Soft Matter, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=911832 (Accessed September 20, 2024)