Year: 2009
Journal: Colloids and Surfaces B: Biointerfaces, Volume 69, Issue 2, 1 March 2009, Pages 201-206, 20111221
Authors: Changchun Hao, Runguang Sun, Jing Zhang, Yiguang Chang and Chunling Niu
Organizations: College of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062, China, College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi’an 710062, China
The monolayer properties of sulfatide and cholesterol binary system have been investigated with surface pressure–mean molecular area isotherms measurements and atomic force microscopy (AFM). The thermodynamic analysis indicates that the obtained negative deviation of the excess molecular area (ΔA(ex)) and surface excess Gibbs energy (ΔG(ex)) from the ideal behavior at various molar ratios, suggesting an attractive interaction between sulfatide and cholesterol in the monolayers as compared with the pure components monolayers. Meanwhile, the compression modulus (
) vs. surface pressure (π) and activity coefficients (f1 and f2) of mixed films dependencies for mixed monolayers are drawn at different mole fractions. The AFM images for the mixed sulfatide/cholesterol monolayers deposited on the mica at 15 and 30 mN m−1 show the stronger molecular attractive force to form condensed structure. The behavior of sulfatide is thought to be involved in lateral domain formation in biological membranes. Therefore, the interaction between sulfatide and cholesterol becomes more important in mimicking “lipid rafts” domains.
