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Spectroscopy
Volume 24 (2010), Issue 3-4, Pages 375-380
http://dx.doi.org/10.3233/SPE-2010-0456

Interaction of alcohol with phospholipid membrane: NMR and XRD investigations on DPPC–hexanol system

U. Wanderlingh,1,3 G. D'Angelo,1 V. Conti Nibali,1 C. Crupi,1 S. Rifici,1 C. Corsaro,1 and G. Sabatino2

1Dipartimento di Fisica, Università di Messina, Messina, Italy
2Dipartimento di Scienze della Terra, Università di Messina, Messina, Italy
3Università di Messina, Sal. Sperone 31, I-98166 S Agata, Messina, Italy

Copyright © 2010 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The investigations of the interaction between phospholipid bilayer and short-chain alcohols are relevant for the potential of lipid bilayer membranes to serve as model systems for studies of various biological processes including permeability of the plasma membrane and molecular mechanisms of anesthesia. Because the hydrophobic portion of an alcohol favorably interacts with lipid hydrocarbon chains, the polar hydroxyl group remains free to form hydrogen bonds with polar lipid atoms that are located near the water/lipid interface. Experiments on phospholipid membranes have shown that alcohols can induce an interdigitated phase and at high concentration even promote the assembly of some lipids into non-bilayer structures within the membrane interior. In this paper we have investigated the DPPC:hexanol system at high alcohol concentration (two molecules per phospholipid) by means of calorimetric, Nuclear Magnetic Resonance, X-ray diffraction and density measurements. We have found that the presence of a high alcohol concentration shifts the membrane transition temperature to lower values, and has a disordering effect on the phospholipid acyl chains in the gel phase. The bilayer spacing and the area of polar head have been also derived for the liquid phase.