Europhys. Lett.
Volume 70, Number 3, May 2005
Page(s) 411 - 417
Section Interdisciplinary physics and related areas of science and technology
Published online 08 April 2005
Europhys. Lett., 70 (3), pp. 411-417 (2005)
DOI: 10.1209/epl/i2004-10498-4

Molecular theory of asymmetrically charged bilayers: Preferred curvatures

Y. Li and B.-Y. Ha

Department of Physics, University of Waterloo - Waterloo, Ontario N2L 3G1, Canada

received 15 December 2004; accepted in final form 17 March 2005
published online 8 April 2005

We study the preferred curvature of asymmetrically charged bilayers (as in red blood cell membranes), in which the inner layer is negatively charged while the outer one is neutral. In particular, we present a molecular theory for the computation of the relaxed-area difference $\Delta A_0$ and the spontaneous curvature C0 of the bilayer. Our approach shows how packing properties of lipids and counterion (e.g., $\chem{Ca^{2+}}$) valence are intertwined. We find that $\chem{Ca^{2+}}$ has a dramatic effect on $\Delta A_0$ and C0: For wide parameter ranges, the presence of 0.1$\un{mM}$ of $\chem{Ca^{2+}}$ ensures positive $\Delta A_0$ and C0 that are nominally negative.

87.15.-v - Biomolecules: structure and physical properties.
87.15.La - Mechanical properties.

© EDP Sciences 2005