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Experimental evidence of the electrostatic contribution to membrane bending rigidity

2004; Institute of Physics; Volume: 67; Issue: 1 Linguagem: Inglês

10.1209/epl/i2003-10276-x

1286-4854

Amy C. Rowat, Per Lyngs Hansen, John H. Ipsen,

Surfactants and Colloidal Systems

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.