Intercalative stacking: A critical feature of DNA charge-transport electrochemistry

Elizabeth M. Boon, Nicole M. Jackson, Matthew D. Wightman, Shana O. Kelley, Michael G. Hill*, Jacqueline K. Barton

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


In electrochemistry experiments on DNA-modified electrodes, features of the redox probe that determine efficient charge transport through DNA-modified surfaces have been explored using methylene blue (MB+) and Ru(NH3)63+ as DNA-binding redox probes. The electrochemistry of these molecules is studied as a function of ionic strength to determine the necessity of tight binding to DNA and the number of electrons involved in the redox reaction; on the DNA surface, MB+ displays 2e-/1H+ electrochemistry (pH 7) and Ru(NH3)63+ displays 1e- electrochemistry. We examine also the effect of the electrode surface passivation and the effect of the mode (intercalation or electrostatic) of MB+ and Ru(NH3)63+ binding DNA to highlight the importance of intercalation for reduction by a DNA-mediated charge-transport pathway. Furthermore, in experiments in which MB+ is covalently linked to the DNA through a σ-bonded tether and ionic strength is varied, it is demonstrated that intercalative stacking rather than covalent σ-bonding is essential for efficient reduction of MB+. The results presented here therefore establish that efficient charge transport to the DNA-binding moiety in DNA films requires intercalative stacking and is mediated by the DNA base pair array.

Original languageEnglish (US)
Pages (from-to)11805-11812
Number of pages8
JournalJournal of Physical Chemistry B
Issue number42
StatePublished - Oct 23 2003
Externally publishedYes

ASJC Scopus subject areas

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


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