Small-Angle Neutron Scattering investigation of cholesterol-doped DMPC liposomes interacting with β-cyclodextrin

The Small-Angle Neutron Scattering technique (SANS) has been applied to characterize the influence of a randomly methylated β–cyclodextrin (CD), called RAMEB, on dimyristoylphosphatidylcholine (DMPC) liposomes doped with cholesterol. From the modelling of the experimental neutron scattering crosssections, the detailed response of the vesicle structure upon addition of increasing amounts of RAMEB up to 30 mM has been assessed. This study has been performed below and above the DMPC bilayer phase transition temperature and shows that cholesterol extraction by RAMEB is linked to a decrease of the average radius and of the aggregation number of the vesicles. This extraction takes place in a dose-dependent way until a more monodisperse population of cholesterol-free liposomes was obtained. In addition, the bilayer thickness evolution was inferred, as well as the liposome coverage by RAMEB.