Regensburg 2007 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 11: INTERNAL SYMPOSIUM Scattering Experiments II
CPP 11.8: Talk
Tuesday, March 27, 2007, 16:30–16:45, H37
Bending elasticity of DPPC vesicles with changing cholesterol content — Laura Rodriguez-Arriaga1, Guillermo Orts-Gil2, •Thomas Hellweg2, Bela Farago3, Carlos Menduina1, and Francisco Monroy1 — 1Departamento de Quimica-Fisica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, E- 28040 Madrid, Spain — 2Stranski Laboratorium, TU Berlin, Strasse des 17.Juni 124, D-10623 Berlin, Germany — 3Institut Laue-Langevin, Grenoble, France
A combination of neutron spin-echo spectroscopy and photon correlation spectroscopy (PCS) can be used to determine motions in colloidal particles in the nanosecond time range [1](e.g. film deformation modes). In the present study we used this approach to discriminate membrane shape fluctuations of DPPC vesicles with different cholesterol content from their translational diffusion. The relative amplitude of the translational contribution to the intermediate scattering functions is found to decrease as q increases and the vesicle deformation mode becomes the main contribution to the relaxation function at times short enough, like the ones probed by the NSE technique. We have performed experiments on vesicles with different lipid composition and we have gained some insight in the compositional grounds of the bending elasticity of these models of cellular membranes. The bending elastic constant κ is calculated using the Zilman-Granek approach.
Th. Hellweg, D. Langevin; PRE, 57 (1998) 6825.