Seminars Archive

Complementary techniques in soft matter sciences: Structure of biological model membranes

Abstract
The use of scattering techniques, available at large scale facilities, are becoming of more and more interest for scientists working in soft matter and bio-oriented sciences. In this context, a Partnership for Soft Condensed Matter (PSCM) between the Institut Laue-Langevin (ILL), the world leading neutron source, and the European Synchrotron Radiation Facility (ESRF) has been established.In this framework the development of better bio-relevant membrane systems started to be addressed. It is known that the behavior of reconstituted model bilayers can differ strongly from that of real cell membranes. For this reason two main strategies were followed. The first one was the use model system to study selected and cell non-specific processes. This is the case of lipid flip-flop and exchange, two molecular movements taking place within cell membranes. Their characterization by neutron reflectometry and small angle scattering will be presented. The second way to study bio-relevant membrane systems was to directly extract lipid molecules from cells to obtain systems whose composition is very close to the natural one. This second route has, as big advantage, the possibility of producing fully deuterated lipid molecules that are fundamental for neutron scattering investigations and usually impossible to be synthetized. The first structural characterization by neutron diffraction of a fully deuterated natural membrane will be presented. Y. Gerelli et al. – “Lipid Exchange and Flip-Flop in solid supported bilayers” Langmuir, 2013 Y. Gerelli et al. – “Lipid rearrangement in DSPC:DMPC bilayers: a neutron reflectometry study” Langmuir, 2012, Y. Gerelli et al. – “Multi-lamellar organization of fully deuterated lipid extracts of yeast membranes” Eur. Phys. J. E Soft Matter, 2013, S. Bobone et al. – "Membrane thickness and the mechanism of action of the short peptaibol trichogin GA IV" Biochim. Biophys. Acta - Biomembranes, 2013,Y. Gerelli et al. – “Structure of Self-Organized Multilayer Nanoparticles for Drug Delivery” Langmuir, 2008