Partial area of cholesterol in monounsaturated diacylphosphatidylcholine bilayers.

The influence of cholesterol on the structural parameters of phosphatidylcholine bilayers is studied by small-angle neutron scattering on unilamellar liposomes. Monounsaturated diacylphosphatidylcholines diCn:1PC with the length of acyl chains n=14, 18 and 22 carbons are used. We confirm that the bilayer thickness increases with increasing concentration of cholesterol for all studied diCn:1PCs. However, partial areas per diCn:1PC and cholesterol molecule on lipid-water interface are found not to depend of cholesterol concentration. The partial area per cholesterol molecule is 0.24nm². In addition, the partial area per diC18:1PC is larger than that for diC14:1PC and diC22:1PC.