Bilayer thickness in unilamellar extruded 1,2-dimyristoleoyl and 1,2-dierucoyl phosphatidylcholine vesicles: SANS contrast variation study of cholesterol effect

摘要

Small-angle neutron scattering on extruded unilamellar vesicles in water was used to study bilayer thickness when cholesterol (CHOL) was added at 44.4 mol% to 1,2-dimyristoleoylphosphatidylcholine (diC14:1PC) and 1,2-dierucoylphosphatidylcholine (diC22:1PC) bilayers. Using the (H2O)-H-1/(H2O)-H-2 contrast variation and the small-angle form of Kratky-Porod approximation, the bilayer gyration radii at infinite contrast R-g.infinity and the bilayer thickness parameters d(g.infinity) = 12(0.5)R(g.infinity) were obtained at 30 degreesC. Addition of cholesterol to diC14:1PC increased the d(g.infinity) from 3.72 +/- 0.02 to 4.26 +/- 0.01 nm, while in the diC22:1PC bilayers the d(g.infinity) change observed was within the experimental error: +0.23 +/- 0.23 nm. (C) 2004 Elsevier B.V. All rights reserved.