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Reduction of Ferricyanide by Methylene Blue at a DNA-Modified Rotating-Disk Electrode

Boon, Elizabeth M. and Barton, Jacqueline K. and Bhagat, Vipin and Nersissian, Migran and Wang, Weidong and Hill, Michael G. (2003) Reduction of Ferricyanide by Methylene Blue at a DNA-Modified Rotating-Disk Electrode. Langmuir, 19 (22). pp. 9255-9259. ISSN 0743-7463. doi:10.1021/la030266u.

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The electrocatalytic reduction of ferricyanide mediated by methylene blue (MB) at a DNA-modified electrode was investigated by linear-sweep voltammetry at a rotating-gold-disk electrode (RDE). Electrodes were modified with thiol-terminated double-stranded oligonucleotides (sequence:  5‘-SH-AGTACAGTCATCCGC-3‘) to form densely packed DNA films that blocked the electrochemical reduction of millimolar solutions of ferricyanide at overpotentials greater than 0.5 V. Addition of micromolar concentrations of MB to these solutions, however, resulted in the rapid appearance of catalytic currents as long as the potential was held negative of the formal potential of MB within the DNA film (−0.30 V vs SCE). MB binds reversibly to these DNA-modified surfaces, and the adsorption kinetics of MB were determined by a coulometric assay. These data fit a simple Langmuir model with k_1 (adsorption) = 7.5(6) × 10^5 M^(-1) s^(-1) and k_(-1) (desorption) = 0.043(8) s^(-1). Interestingly, linear-sweep RDE voltammograms recorded in the presence of MB revealed “peaked”-shaped i−V traces, which took several seconds to reach their steady-state values. Moreover, the steady-state current density for reduction of Fe(CN)_6^(3-) was found to depend on the bulk concentration of MB in solution. A model is proposed to account for these data in which Fe(CN)_6^(3-) turnover is limited ultimately by the kinetics of MB crossing into and out of the film, and the chemical reaction between Fe(CN)_6^(3-) and reduced MB occurs at the film/solution interface.

Item Type:Article
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Boon, Elizabeth M.0000-0003-1891-839X
Barton, Jacqueline K.0000-0001-9883-1600
Additional Information:© 2003 American Chemical Society. Received 30 June 2003. Published online 4 October 2003. Published in print 1 October 2003. We are grateful to the NIH (GM61077) for financial support of this work. We also thank Prof. F. C. Anson for helpful discussions.
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Issue or Number:22
Record Number:CaltechAUTHORS:20170427-100416986
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Official Citation:Reduction of Ferricyanide by Methylene Blue at a DNA-Modified Rotating-Disk Electrode Elizabeth M. Boon, Jacqueline K. Barton, Vipin Bhagat, Migran Nersissian, Weidong Wang, and Michael G. Hill Langmuir 2003 19 (22), 9255-9259 DOI: 10.1021/la030266u
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76993
Deposited By: Ruth Sustaita
Deposited On:27 Apr 2017 22:27
Last Modified:15 Nov 2021 17:04

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