title: 'Turn-on' detection of Hg2+ ion using a peroxidase-like split G-quadruplex-hemin DNAzyme.
abstract: A highly sensitive and selective Hg(2+) detection method was developed based on the Hg(2+)-mediated formation of split G-quadruplex-hemin DNAzymes. In this method, two label-free oligonucleotides are used. In the presence of Hg(2+), the two oligonucleotides hybridize to each other to form a duplex, in which T-T mismatches are stabilized by T-Hg(2+)-T base pair. As a result, the G-rich sequences of the two oligonucleotides can associate to form a split G-quadruplex, which is able to bind hemin to form the catalytically active G-quadruplex-hemin DNAzymes. This can be reflected by an absorbance increase when monitored in the H(2)O(2)-ABTS (2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid) reaction system by using UV-vis absorption spectroscopy. This 'turn-on' process allows the detection of aqueous Hg(2+) at concentrations as low as 19 nM using a simple colorimetric technique. With the development of the studies on metal-base pairs, this Hg(2+)-sensing method can be easily extended to the analysis of other metal ions.
authors.affiliation: Key Laboratory of Functional Polymer Materials, Ministry of Education, Nankai University, Tianjin, 300071, People's Republic of China. kongdem@nankai.edu.cn
authors.forename: De-Ming
authors.initials: DM
authors.lastname: Kong
authors.forename: Na
authors.initials: N
authors.lastname: Wang
authors.forename: Xiao-Xuan
authors.initials: XX
authors.lastname: Guo
authors.forename: Han-Xi
authors.initials: HX
authors.lastname: Shen
mesh_terms: D020137:Base Pair Mismatch; D001483:Base Sequence; D002942:Circular Dichroism; D021881:DNA, Catalytic / Q000737:chemistry*; D054856:G-Quadruplexes; D006427:Hemin / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*; D009841:Oligonucleotides / Q000737:chemistry; D009195:Peroxidase / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*
chemical_list: D021881:DNA, Catalytic; D009841:Oligonucleotides; D006427:Hemin; D009195:Peroxidase; D008628:Mercury