Thymine-Hg2+-thymine coordination chemistry induced entropy driven catalytic reaction to form Hemin/G-quadruplex-HRP-mimicking DNAzyme for colorimetric and visual determination of Hg2.

A sensitive and visible colorimetric strategy was proposed for Hg2+ detection by thymine-Hg2+-thymine (T-Hg2+-T) coordination chemistry and entropy driven catalytic reaction. The entropy driven catalytic reaction is induced by T-Hg2+-T coordination chemistry, resulting the releasing of G-riched sequence. Hemin/G-quadruplex-HRP-mimicking DNAzyme can be formed with the help of hemin, catalyzing TMB to TMB+ with a color change from colorless to blue. The sensitivity of this strategy can be reached to 2 pM, which is significantly improved by entropy driven catalytic reaction. In addition, entropy driven catalytic reaction provides a more reliable and accurate results. This method shows great promise for on-site analysis and in-house diagnosis of Hg2+ in water.