Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 10: Interfaces and Thin Films II
CPP 10.1: Topical Talk
Dienstag, 27. März 2012, 09:30–10:00, C 130
PEG Functionalized Lipid Bilayers at the Solid / Liquid Interface: Protrusions versus Blisters — •Beate Klösgen1, Giovanna Fragneto2, Avi Halperin3, Ole G. Mouritsen1, Patricia Hardas4, and Michele Sferrazza4 — 1University of Southern Denmark, Odense, Denmark — 2Institute Laue-Langevin, Grenoble, France — 3Université Joseph Fourier, Grenoble, France — 4Université Libre de Bruxelles, Bruxelles, Belgique
PEGylated lipids inoculated into fluid membranes constitute a membrane disturbance due to conformational restrictions of the polymer when grafted to the membrane interface. Blisters and protrusions were both discussed as possible responses to the hydrophilic pull. Neutron reflectivity of adsorbed lipid membranes at the solid/water interface supports the protrusion model. Results are shown from an asymmetric system with an inner leaflet consisting of 1,2-distearoyl-sn-glycero-3-phosphorylcholine (DSPC) and an outer leaflet composed of DSPC and Polyethylene glycol (PEG) functionalized 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE-PEG). DSPC headgroups were deuterated to enhance sensitivity and mark the lipid headgroup/water interface. A narrow water layer at the inner interface allows for some membrane deformation, equally found for the outer headgroup layer in the absence of polymer. This roughness is enhanced when PEG chains are present; the roughness of the inner headgroup layer is about constant. The outer headgroup layer roughness increases with PEG-lipid mole fraction and temperature. The findings suggest that PEG chains favour headgroup protrusions rather than blister like deformations.