Polyhedral MnSe microparticles with specific Hg2+-suppressed oxidase-like activity: Toward a green and low-cost turn-off method for Hg2+ detection

With the attractive advantage of catalytic signal amplification, noble metal-based peroxidase-mimicking nano -materials have been intensively used to establish optical methods for hypertoxic Hg2+ detection. However, in these methods the requirement of high-concentration H2O2 can lead to secondary pollution, and the noble metals used result in these assays' high cost. Therefore, exploring new categories of enzyme mimics to develop envi-ronmentally friendly and low-cost approaches for Hg2+ sensing is highly desired. Herein we proposed a novel noble metal-free material, MnSe microparticles, featuring specific Hg2+-suppressed oxidase-like catalytic activ-ity, to fabricate a green, cheap, and high-performance turn-off approach for Hg2+ detection. The MnSe micro -particles with a polyhedral structure were obtained via a one-pot solvothermal process, showing excellent oxidase-like activity to catalyze the oxidation of colorless 3,3 ',5,5 '-tetramethylbenzidine (TMB) to its blue product. The introduction of Hg2+ can significantly mask their active sites via forming an inert layer of HgSe outside the MnSe microparticles, thus suppressing the TMB catalytic color reaction. Based on the turn-off principle, colorimetric quantification of Hg2+ was realized with high sensitivity and specificity. By integrating smartphone sensing with 3D-printed accessories and paper strips, a portable platform for the convenient detection of Hg2+ was further established, demonstrating its great practicability in real analysis.

Automated summary

In this study, a novel noble metal-free material, MnSe microparticles, with Hg2+-suppressed oxidase-like catalytic activity, was proposed for the fabrication of a green, cheap, and high-performance turn-off approach for Hg2+ detection. By integrating smartphone sensing with 3D-printed accessories, a portable platform for the convenient detection of Hg2+ was established, demonstrating its great practicability in real analysis.