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Issue 43, 2016
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A photoelectrochemical DNA sensor for the detection of Hg2+ based on Hg2+-mediated oligonucleotide switching

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Abstract

A sensitive photoelectrochemical (PEC) method for Hg2+ detection is reported, based on the Hg2+-mediated structural switch of an oligonucleotide strand and biocatalytic precipitation (BCP) on a CdS quantum dot electrode. The principle is that, in the absence of Hg2+, the oligonucleotide strand forms a stem-loop, thus a G-rich sequence in the strand is partially caged in the stem-loop structure and cannot fold into a G-quadruplex. While in the presence of Hg2+, the T–Hg2+–T coordination leads to the formation of another stem-loop structure and allows the G-rich sequence to fold properly and bind hemin to form a stable G-quadruplex/hemin complex, which could accelerate oxidation of 4-chloro-1-naphthol (4-CN) by H2O2 to yield the insoluble (BCP reaction) and insulating product benzo-4-chlorohexadienone on the photoelectrode, thereby efficiently causing the change in the photocurrent signal. This simple PEC sensor could detect aqueous Hg2+ at concentrations as low as 4 nM with high selectivity.

Graphical abstract: A photoelectrochemical DNA sensor for the detection of Hg2+ based on Hg2+-mediated oligonucleotide switching

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Publication details

The article was received on 06 Aug 2016, accepted on 30 Sep 2016 and first published on 03 Oct 2016


Article type: Paper
DOI: 10.1039/C6AY02222G
Citation: Anal. Methods, 2016,8, 7762-7766
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    A photoelectrochemical DNA sensor for the detection of Hg2+ based on Hg2+-mediated oligonucleotide switching

    W. Zhang, B. Shan, D. Liang, Y. Shi, D. Han and C. Huang, Anal. Methods, 2016, 8, 7762
    DOI: 10.1039/C6AY02222G

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