Modulation of Elasticity and Interactions in Charged Lipid Multibilayers: Monovalent Salt Solutions

Bing Sui Lu*, Santosh Prasad Gupta, Michal Belička, Rudolf Podgornik, Georg Pabst

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)13546-13555
Number of pages10
JournalLangmuir
Volume32
Issue number50
DOIs
Publication statusPublished - 20 Dec 2016
Externally publishedYes

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