A label-free G-quadruplex-based mercury detection assay employing the exonuclease III-mediated cleavage of T-Hg(2+)-T mismatched DNA

We report herein the use of an exonuclease III and G-quadruplex probe to construct a G-quadruplex-based luminescence detection platform for Hg(2+). Unlike common DNA-based Hg(2+) detection methods, when using the dsDNA probe to monitor the hairpin formation, the intercalation of the dsDNA probe may be influenced by the distortion of dsDNA. This 'mix-and-detect' methodology utilized the G-quadruplex probe as the signal transducer and is simple, rapid, convenient to use and can detect down to 20 nM of Hg(2+).