Eur. Phys. J. E (2007) 23: 247-254
https://doi.org/10.1140/epje/i2007-10202-8

Regular Article

Influence of cholesterol on the bilayer properties of monounsaturated phosphatidylcholine unilamellar vesicles

¹ Canadian Neutron Beam Centre, National Research Council, K0J 1P0, Chalk River, Ontario, Canada
² Department of Physical Chemistry of Drugs, Faculty of Pharmacy, Comenius University, 832 32, Bratislava, Slovakia
³ Guelph-Waterloo Physics Institute and Biophysics Interdepartmental Group, University of Guelph, N1G 2W1, Guelph, Ontario, Canada
⁴ Department of Physics, Brock University, 500 Glenridge Avenue, L2S 3A1, St. Catharines, Ontario, Canada

^* e-mail: Norbert.Kucerka@nrc.gc.ca
^** e-mail: John.Katsaras@nrc.gc.ca

Received: 19 March 2007
Accepted: 30 May 2007
Published online: 5 July 2007

Abstract

The influence of cholesterol on the structure of unilamellar-vesicle (ULV) phospholipid bilayers is studied using small-angle neutron scattering. ULVs made up of short-, mid- and long-chain monounsaturated phospholipids (diCn :1PC, n = 14 , 18, 22, respectively) are examined over a range (0-45mol %) of cholesterol concentrations. Cholesterol's effect on bilayer structure is characterized through changes to the lipid's transmembrane thickness, lateral area and headgroup hydration. For all three lipids, analysis of the experimental data shows that the addition of cholesterol results in a monotonic increase of these parameters. In the case of the short- and mid-chain lipids, this is an expected result, however, such a finding was unexpected for the long-chain lipid. This implies that cholesterol has a pronounced effect on the lipid's hydrocarbon chain organization.