Issue 4, 2013

Denaturation of dsDNA immobilised at a negatively charged gold electrode is not caused by electrostatic repulsion

Abstract

Double-stranded DNA immobilised through a thiol anchor at a gold electrode surface can be unwound and denatured by applying a negative potential. One proposed mechanism for this electrochemical denaturation is that electrostatic field effects are responsible for the destabilisation of the dsDNA through repulsion of the DNA sugar-phosphate backbone away from the electrode surface. Herein, we demonstrate conclusively that electrochemical melting at gold electrodes cannot be explained solely as a simple repulsion mechanism by showing that immobilised DNA denatures at high ionic strengths, where the DNA base-pairs are situated outside of the electrochemical double-layer (and outside the influence of the electric field), and further, that oligomers comprised of the mimic peptide nucleic acid (PNA) can also be denatured at negative potentials, despite the absence of a negatively charged backbone.

Graphical abstract: Denaturation of dsDNA immobilised at a negatively charged gold electrode is not caused by electrostatic repulsion

Supplementary files

Article information

Article type
Edge Article
Submitted
04 Dec 2012
Accepted
22 Jan 2013
First published
22 Jan 2013
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry

Chem. Sci., 2013,4, 1625-1632

Denaturation of dsDNA immobilised at a negatively charged gold electrode is not caused by electrostatic repulsion

R. P. Johnson, N. Gale, J. A. Richardson, T. Brown and P. N. Bartlett, Chem. Sci., 2013, 4, 1625 DOI: 10.1039/C3SC22147D

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