Given the huge threat of Hg2+ to human health, it is always significant to develop Hg2+ monitoring tools. Utilizing its impacts on nanozyme catalysis is a promising strategy to realize Hg2+ detection. However, nearly all the assays fabricated based on the principle should be performed in solution and in laboratory and require bulky signal reading instruments, hindering their wider applications. It is highly desired to develop portable, efficient, and practical Hg2+ sensors. Herein, we proposed the in situ controllable growth of Ag nanoparticles (AgNPs) on paper to fabricate a smartphone optica...
