Eur. Phys. J. E (2013) 36: 3
https://doi.org/10.1140/epje/i2013-13003-6

Regular Article

Neutron reflectivity of supported membranes incorporating terminally anchored polymers: Protrusions vs. blisters

¹ Institute Max von Laue - Paul Langevin, 6 rue Jules Horowitz, BP 156, 38042, Grenoble, France
² Université de Grenoble 1/CNRS, LIPhy UMR 5588, BP 87, 38041, Grenoble, France
³ Department of Physics, Chemistry and Pharmacy, and MEMPHYS, Center for Biomembrane Physics, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
⁴ Département de Physique, Faculté des Sciences, Université Libre de Bruxelles, Boulevard du Triomphe, 1050, Bruxelles, Belgium

^* e-mail: fragneto@ill.eu

Received: 16 September 2012
Revised: 28 November 2012
Accepted: 17 December 2012
Published online: 17 January 2013

Abstract

The effect of terminally anchored chains on the structure of lipid bilayers adsorbed at the solid/water interface was characterized by neutron reflectivity. In the studied system, the inner leaflet, closer to the substrate, consisted of head-deuterated 1,2-distearoyl-sn-glycero-3-phosphorylcholine (DSPC) and the outer leaflet comprised a mixture of DSPC and polyethylene glycol (PEG) functionalized 1,2-distearoyl-sn-glycero-3-phosphoethanolamine. The DSPC headgroups were deuterated to enhance sensitivity and demarcate the bilayer/water interface. The effect on the inner and outer headgroup layers was characterized by w _1/2 , the width at half-height of the scattering length density profile. The inner headgroup layer was essentially unperturbed while w _1/2 of the outer layer increased significantly. This suggests that the anchored PEG chains give rise to headgroup protrusions rather than to blister-like membrane deformations.