Overcharging of DNA in the presence of salt: Theory and simulation

Markus Deserno, Felipe Jiménez-Ángeles, Christian Holm, Marcelo Lozada-Cassou*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

119 Scopus citations


A study of a model rodlike polyelectrolyte molecule immersed in a monovalent or divalent electrolyte is presented. Results for the local concentration profile, mean electrostatic potential, charge distribution function, and ζ-potential are obtained from hypernetted-chain/mean spherical approximation (HNC/MSA) theory and compared with molecular dynamics (MD) simulations. As a particular case, the parameters of the polyelectrolyte molecule are mapped to those of a DNA molecule. Both HNC/MSA and MD predict the occurrence of overcharging, which is not present in the Poisson-Boltzmann theory. Further an excellent qualitative, and in some cases quantitative, agreement between HNC/MSA and MD is found. Oscillations observed in the mean electrostatic potential, local concentration profiles, and the curvature of the ζ-potential are discussed in terms of the observed overcharging effect. Particularly interesting results are a very nonmonotonic behavior of the ζ-potential, as a function of the rod charge density, and the overcharging by monovalent counterions.

Original languageEnglish (US)
Pages (from-to)10983-10991
Number of pages9
JournalJournal of Physical Chemistry B
Issue number44
StatePublished - Nov 8 2001
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry


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