Recently, there has been an explosion of interest in the use of nanomaterials for the development of novel Hg2+ sensors. Metal nanoclusters have been utilized as Hg2+ sensors based on the quenching of their fluorescence. For instance, 11-MUA-capped gold nanoclusters (AuNCs) were capable of sensing Hg2+ based on Hg2+ induced aggregation of AuNCs.13 BSA-stabilized AuNCs were also demonstrated to be selective and sensitive for the detection of Hg2+ owing to the high-affinity metallophilic Hg2+–Au+ interactions, which efficiently quenched the fluorescence of AuNCs.14 Silver nanoclusters (AgNCs) stabilized by DNA oligonucleotides,15 small mole-cules16 or polymers17 were widely used in the “turn-off” detec-tion of Hg2+ as well. Besides, the fluorescence of carbon quantum dots was also found to be quenched by Hg2+ through nonradiative electron-transfer from the excited states to the d orbital of Hg2+.18 What’s more, metal nanoparticles, such as gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs), which have unique optical, electronic, and catalytic ability, have attracted much attention for the detection of Hg2+ by the colorimetric or fluorescence method.19–23 Because Hg2+ can selectively coordinate thymine (T) bases and form stable T–Hg2+–T complexes, DNA-functionalized AuNPs have been widely used as a colorimetric Hg2+ sensor.24–26 However, most