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Issue 3, 2013
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Controlling interfacial electron transfer and electrocatalysis by pH- or ion-switchable DNA monolayer-modified electrodes

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Abstract

pH-stimulated formation and dissociation of i-motif DNA nanostructures associated with electrodes lead to the control of interfacial electron transfer resistances in the presence of Fe(CN)63−/4− as a redox label (measured by Faradaic impedance spectroscopy). While at neutral pH (pH = 7.0), the interfacial electron transfer resistance is high, Ret ∼ 500 Ω, in the presence of the i-motif nanostructure (pH = 5.8) it decreases to Ret ∼ 300 Ω. By cycling the pH of the solution between the values 7.0 and 5.8, the electron transfer resistances are reversibly switched between high and low values, respectively. The switchable charge transport at the modified electrode is rationalized in terms of the electrostatic interactions between the modified electrode and the redox label. Similarly, the generation of a G-quadruplex through the formation of an aptamer–AMP complex leads to the control of the interfacial electron transfer resistance. The i-motif- or G-quadruplex-controlled electron transfer resistances are implemented to yield the switchable electrocatalyzed reduction of H2O2 in the presence of negatively charged, citrate-stabilized, Ag nanoparticles.

Graphical abstract: Controlling interfacial electron transfer and electrocatalysis by pH- or ion-switchable DNA monolayer-modified electrodes

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Supplementary files

Article information


Submitted
10 Oct 2012
Accepted
16 Dec 2012
First published
18 Dec 2012

Chem. Sci., 2013,4, 1137-1144
Article type
Edge Article

Controlling interfacial electron transfer and electrocatalysis by pH- or ion-switchable DNA monolayer-modified electrodes

G. Pelossof, R. Tel-Vered, S. Shimron and I. Willner, Chem. Sci., 2013, 4, 1137
DOI: 10.1039/C2SC22193D

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