Autori: Tomoaia-Cotisel, M. , Pasca, R.-D., Horovitz, O., Mocanu, A.
Editorial: Revue Roumaine de Chimie, 56 (10-11), p.1047-1053, 2011.
The behaviour of cholesterol (CHO) and dimyristoyl phosphatidylcholine (DMPC), as well as of their mixed monolayers of various compositions has been investigated by surface potential (δV) measurements at the air/water interface for different surface pressures, using Langmuir technique coupled with the vibrating plate method. Isotherms of δV versus mean molecular area, A, at different cholesterol mole fractions, xCHO, were recorded, and δV versus monolayer composition curves were constructed for various constant lateral surface pressures. From δV data, the component of the dipole moment perpendicular to the monolayer plane was estimated, and its variation with A and xCHO was investigated. Our results indicate strong interactions between DMPC and CHO molecules, possibly leading to well defined nanostructures, plausible to occur in natural membranes. Besides hydrogen bonds between DMPC carbonyl and CHO hydroxyl groups, electrostatic and van der Waals interactions increase the ability of these biomolecules to generate nanostructured domains at fluid interfaces.
Cuvinte cheie: AFM