title: Modulation of Elasticity and Interactions in Charged Lipid Multibilayers: Monovalent Salt Solutions.
abstract: We have studied the electrostatic screening effect of NaCl solutions on the interactions between anionic lipid bilayers in the fluid lamellar phase using a Poisson-Boltzmann-based mean-field approach with constant charge and constant potential limiting charge regulation boundary conditions. The full DLVO potential, including the electrostatic, hydration and van der Waals interactions, was coupled to thermal bending fluctuations of the membranes via a variational Gaussian Ansatz. This allowed us to analyze the coupling between the osmotic pressure and the fluctuation amplitudes and compare them both simultaneously with their measured dependence on the bilayer separation, determined by the small-angle X-ray scattering experiments. High-structural resolution analysis of the scattering data revealed no significant changes of membrane structure as a function of salt concentration. Parsimonious description of our results is consistent with the constant charge limit of the general charge regulation phenomenology, with fully dissociated lipid charge groups, together with a 6-fold reduction of the membranes' bending rigidity upon increasing NaCl concentration.
authors.affiliation: Department of Theoretical Physics, Jožef Stefan Institute , 1000 Ljubljana, Slovenia.|School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, 637371 Singapore.
authors.forename: Bing-Sui
authors.initials: BS
authors.lastname: Lu
authors.affiliation: Institute of Molecular Biosciences, Biophysics Division, University of Graz , NAWI Graz, Humboldtstraße 50/III, A-8010 Graz, Austria.|BioTechMed-Graz , A-8010 Graz, Austria.
authors.forename: Santosh Prasad
authors.initials: SP
authors.lastname: Gupta
authors.affiliation: Institute of Molecular Biosciences, Biophysics Division, University of Graz , NAWI Graz, Humboldtstraße 50/III, A-8010 Graz, Austria.|BioTechMed-Graz , A-8010 Graz, Austria.
authors.forename: Michal
authors.initials: M
authors.lastname: Belička
authors.affiliation: Department of Theoretical Physics, Jožef Stefan Institute , 1000 Ljubljana, Slovenia.|Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana , Jadranska ulica 19, SI-1000 Ljubljana, Slovenia.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Podgornik
authors.affiliation: Institute of Molecular Biosciences, Biophysics Division, University of Graz , NAWI Graz, Humboldtstraße 50/III, A-8010 Graz, Austria.|BioTechMed-Graz , A-8010 Graz, Austria.
authors.forename: Georg
authors.identifier: 0000-0003-1967-1536
authors.initials: G
authors.lastname: Pabst
mesh_terms: D000838:Anions; D004548:Elasticity; D008051:Lipid Bilayers / Q000737:chemistry*; D009997:Osmotic Pressure; D055672:Static Electricity
chemical_list: D000838:Anions; D008051:Lipid Bilayers