Experimental evidence of the electrostatic contribution to membrane bending rigidityA. C. Rowat, P. L. Hansen and J. H. Ipsen
MEMPHYS - Centre for Biomembrane Physics, Department of Physics University of Southern Denmark - Campusvej 55, DK-5230 Odense, Denmark
(Received 25 November 2003; accepted in final form 28 April 2004)
We have investigated the thermal fluctuations of giant unilamellar dimyristoylphosphatidlycholine vesicles in the presence of both non-ionic and ionic surfactants (peptides) with identical apolar chains. Using vesicle fluctuation analysis, the effects of ionic and non-ionic surfactants upon membrane bending rigidity in the case of no added salt have been determined and the electrostatic contribution thereby isolated. We interpret these experimental findings in terms of a mean-field free-energy model for the adsorption of charged surfactants to a lipid bilayer and couple these results to describe the electrostatic contribution to membrane bending rigidity. This experimental study demonstrates how electrostatics affect the elastic properties of unilamellar bilayers.
87.16.Dg - Membranes, bilayers, and vesicles.
41.20.Cv - Electrostatics; Poisson and Laplace equations, boundary-value problems.
62.20.Dc - Elasticity, elastic constants.
© EDP Sciences 2004