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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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Publication details

The article was received on 10 Oct 2012, accepted on 16 Dec 2012 and first published on 18 Dec 2012


Article type: Edge Article
DOI: 10.1039/C2SC22193D
Citation: Chem. Sci., 2013,4, 1137-1144
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    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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