Electrostatic and electrokinetic contributions to the elastic moduli of a driven membrane
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Author(s)
Lacoste, David
Menon, G. I.
Bazant, Martin Z.
Joanny, J. F.
Date Issued
January 2009
Journal
European Physical Journal E: Soft Matter and Biological Physics
Publisher
Springer-Verlag
Citation
Lacoste, D. et al. “Electrostatic and Electrokinetic Contributions to the Elastic Moduli of a Driven Membrane.” The European Physical Journal E 28.3 (2009): 243–264. Web.
Version
Author's final manuscript
Abstract
We discuss the electrostatic contribution to the elastic moduli of a cell or artificial membrane
placed in an electrolyte and driven by a DC electric field. The field drives ion currents across the membrane,
through specific channels, pumps or natural pores. In steady state, charges accumulate in the Debye layers
close to the membrane, modifying the membrane elastic moduli. We first study a model of a membrane
of zero thickness, later generalizing this treatment to allow for a finite thickness and finite dielectric
constant. Our results clarify and extend the results presented by D. Lacoste, M. Cosentino Lagomarsino,
and J.F. Joanny (EPL 77, 18006 (2007)), by providing a physical explanation for a destabilizing term
proportional to k[3 over up tack] in the fluctuation spectrum, which we relate to a nonlinear (E[superscript 2]) electrokinetic effect called induced-charge electro-osmosis (ICEO). Recent studies of ICEO have focused on electrodes and polarizable particles, where an applied bulk field is perturbed by capacitive charging of the double layer and drives the flow along the field axis toward surface protrusions; in contrast, we predict “reverse” ICEO flows around driven membranes, due to curvature-induced tangential fields within a nonequilibrium double layer, which hydrodynamically enhance protrusions. We also consider the effect of incorporating the dynamics of a spatially dependent concentration field for the ion channels.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
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DOI of Published Version
https://doi.org/10.1140/epje/i2008-10433-1
