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

Johnson, Robert P. and Gale, Nittaya and Richardson, James A. and Brown, Tom and Bartlett, Philip N. (2013) Denaturation of dsDNA immobilised at a negatively charged gold electrode is not caused by electrostatic repulsion. Chemical Science, 4 (4). p. 1625. ISSN 2041-6520

Full content URL: https://doi.org/10.1039/C3SC22147D

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Item Type:Article
Item Status:Live Archive

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.

Keywords:SERS, DNA, Electrochemical Melting, Raman Spectroscopy
Subjects:F Physical Sciences > F170 Physical Chemistry
Divisions:College of Science > School of Chemistry
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ID Code:27413
Deposited On:17 May 2017 14:53

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