2020 Impact factor 1.890
Soft Matter and Biological Physics
Eur. Phys. J. E 1, 345-349

Interactions between charged rods near salty surfaces

R. Menes1 - N. Grønbech-Jensen2 - P.A. Pincus1

1 Materials Research Laboratory, University of California, Santa Barbara, CA 93106, USA
2 Department of Applied Science, University of California, Davis, CA 95616, USA
NERSC, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
menes@mrl.ucsb.edu

Received 28 September 1999

Abstract
Using both theoretical modeling and computer simulations we study a model system for DNA interactions in the vicinity of charged membranes. We focus on the polarization of the mobile charges in the membranes due to the nearby charged rods (DNA) and the resulting screening of their fields and inter-rod interactions. We find, both within a Debye-Hückel model and in Brownian dynamics simulations, that the confinement of the mobile charges to the surface leads to a qualitative reduction in their ability to screen the charged rods to the degree that the fields and resulting interactions are not finite-ranged as in systems including a bulk salt concentration, but rather decay algebraically and the screening effect is more like an effective increase in the multipole moment of the charged rod.

PACS
87.68.+z Biomaterials and biological interfaces - 87.16.Dg Membranes bilayers and vesicles - 68.10.-m Fluid surfaces and fluid-fluid interfaces

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