Hexavalent Chromium as an Electrocatalyst in DNA Sensing

Hamid R. Lotfi Zadeh Zhad, Rebecca Y. Lai

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We report for the first time the use of hexavalent chromium (Cr(VI)) as an electrocatalyst in electrochemical DNA sensing. For both stem-loop probe and linear probe electrochemical DNA sensors, the increase in probe rigidity upon target hybridization alters the accessibility of Cr(VI) to the methylene blue label on the surface-immobilized DNA probes. This change results in an enhancement in the electrocatalytic current when the sensors are interrogated using cyclic voltammetry at a slow scan rate. The incorporation of this electrocatalyst does not affect the normal "signal-off" sensing behavior observed in alternating current voltammetry; instead it enables simultaneous "signal-on" and "signal-off" detection of the target, while maintaining noted attributes of this class of folding- and dynamics-based sensors such as reusability and high selectivity. It is also capable of improving the limit of detection of the sensors by an order of magnitude. Importantly, this accessibility-based electrocatalytic sensing strategy is versatile and can potentially be used with other folding- and dynamics-based electrochemical biosensors.

Original languageEnglish (US)
Pages (from-to)13342-13348
Number of pages7
JournalAnalytical Chemistry
Issue number24
StatePublished - Dec 19 2017

ASJC Scopus subject areas

  • Analytical Chemistry


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