Colorimetric Detection of Mercuric Ion (Hg2+) in Aqueous Media using DNA-Functionalized Gold Nanoparticles

Color is everything: Hg2+ in aqueous media is detected by the formation of thymidine–Hg2+–thymidine coordination complexes, which raises the melting temperature of the DNA‐hybridized gold nanoparticle probes and thus the temperature at which the probes disperse and effect a purple‐to‐red color change. The method has very high sensitivity and selectivity, and it provides a simple and fast colorimetric readout (see picture).