A photoelectrochemical DNA sensor for the detection of Hg2+ based on Hg2+-mediated oligonucleotide switching. Issue 43 (21st October 2016)

• Record Type: Journal Article
• Authors: Zhang, Weibo; Shan, Beibei; Liang, Danxia; Shi, Yaying; Han, Deman; Huang, Chaobiao
• Is Part Of: Analytical methods. Volume 8:Issue 43(2016)
• Page Start: 7762
• Page End: 7766
• Publication Date: 2016-10-21
• Subjects: Chemistry, Analytic -- Periodicals; Analytical biochemistry -- Periodicals; Chemical laboratories -- Standards -- Periodicals; 543.1905
• DOI: 10.1039/c6ay02222g
• Languages: English
• ISSNs: 1759-9660

Abstract

Abstract : A sensitive photoelectrochemical (PEC) method for Hg 2+ detection is reported, based on the Hg 2+ -mediated structural switch of an oligonucleotide strand and biocatalytic precipitation (BCP) on a CdS quantum dot electrode. Abstract : A sensitive photoelectrochemical (PEC) method for Hg 2+ detection is reported, based on the Hg 2+ -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 Hg 2+, 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 Hg 2+, the T–Hg 2+ –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 H2 O2 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 Hg 2+ at concentrations as low as 4 nM with high selectivity.