Eur. Phys. J. E (2013) 36: 75
https://doi.org/10.1140/epje/i2013-13075-2

Regular Article

Bending stiffness of biological membranes: What can be measured by neutron spin echo?

¹⁹⁸⁸⁶ Departamento de Química Física I, Universidad Complutense de Madrid, E-28040, Madrid, Spain
²⁹⁸⁸⁶ Physikalische Chemie I, Univeristät Bayreuth, Universitätsstraße 30, D-95447, Bayreuth, Germany
³⁹⁸⁸⁶ Physikalische und Biophysikalische Chemie I, Universität Bielefeld, Universitätsstraße 25, D-33615, Bielefeld, Germany
⁴⁹⁸⁸⁶ TOF/HR Group, Institut Laue Langevin, 6 rue Jules Horowitz, BP156, F-38042, Grenoble Cedex 9, France
⁵⁹⁸⁸⁶ DS/LSS - ILL Soft Matter Partnership Lab, Institut Laue Langevin, 6 rue Jules Horowitz, BP156, F-38042, Grenoble Cedex 9, France

^* e-mail: thomas.hellweg@uni-bielefeld.de
^** e-mail: monroy@quim.ucm.es

Received: 9 October 2012
Revised: 10 April 2013
Accepted: 21 May 2013
Published online: 16 July 2013

Abstract

Large vesicles obtained by the extrusion method represent adequate membrane models to probe membrane dynamics with neutron radiation. Particularly, the shape fluctuations around the spherical average topology can be recorded by neutron spin echo (NSE). In this paper we report on the applicable theories describing the scattering contributions from bending-dominated shape fluctuations in diluted vesicle dispersions, with a focus on the relative relevance of the master translational mode with respect to the internal fluctuations. Different vesicle systems, including bilayer and non-bilayer membranes, have been scrutinized. We describe the practical ranges where the exact theory of bending fluctuations is applicable to obtain the values of the bending modulus from experiments, and we discuss about the possible internal modes that could be alternatively contributing to shape fluctuations.