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Journal of Sensors
Volume 2011, Article ID 735279, 6 pages
Research Article

Electrochemical Capacitance DNA Sensing at Hairpin-Modified Au Electrodes

Department of Chemistry and Center for Advanced Nanoscale Materials, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan, PR 00931-3346, USA

Received 1 September 2010; Revised 7 April 2011; Accepted 23 June 2011

Academic Editor: Jiri Homola

Copyright © 2011 Joel Rivera-Gandía et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


An interfacial capacitance measurement electrochemical technique has been used for the sensing of self-assembled DNA hairpin probes (M. tuberculosis and B. anthracis) attached to Au electrodes. The double-layer capacitance ( ) was determined with electrochemical perturbations from 0.2 V to 0.5 V versus Ag/AgCl at a Au/M. tuberculosis DNA hairpin probe at surface coverage Au electrodes. The capacitance study was done at pH 7, which was necessary to maintain the M. tuberculosis and B. anthracis DNA probes closed during the electrochemical perturbation. Detailed experimental analysis carried out by repetitively switching the electrochemical potential between 0.2 and 0.5 V (versus Ag/AgCl) strongly supports the use of capacitance measurements as a tool to detect the hybridization of DNA targets. A large change in the capacitance deference between 0.2 and 0.5 V was observed in the DNA hybridization process. Therefore, no fluorophores or secondary transducers were necessary to sense a DNA target for both DNA hairpins.