Bending rigidity of lipid bilayers in electrolyte solutions of sucrose

The morphology and dynamics of lipid bilayers are related to their mechanical parameters such as the bending elasticity and the intermonolayer friction. The thermal shape fluctuation analysis of nearly spherical giant lipid vesicles has been established as a versatile tool for the non-invasive measurement of the membrane bending modulus. We applied this method for probing the membrane mechanics in electrolyte solutions of sucrose. The bending rigidity of lipid membranes in aqueous solutions of mono-, di- and polysaccharides was quantified by means of a holographic tool that allows performing quantitative phase measurements for reconstituting the vesicle shape. The analysis of the time autocorrelations of vesicles’ diameters along the optical axis yields the membrane tension and bending modulus. The obtained results indicate that the presence of sodium chloride modifies the effect of sucrose on the bending rigidity of lipid bilayers. Our finding is discussed in the light of the calorimetric and molecular dynamics data in the literature about the ion-induced modification of the membrane interactions with this disaccharide. We present further evidences about the softening of lipid bilayers in sucrose-containing aqueous environment.SCOPUS: ar.j