Colorimetric detection of toxic metal ions in water on the basis of gold nanoparticles

The determinations of Hg2+, Pb2+, and Cd2+ have always under the spotlight, attracting people’s attention due to their notorious toxicity and, as a result, inducing water contamination and severe harm to human beings. In recent years, the gold NP-based colorimetric assay has become one of the most convenient, powerful, and potential means of water sensing because of its unique optical properties. Here the recent impressive results in the development of gold NP-based colorimetric determination for Hg2+, Pb2+, and Cd2+ are introduced. Moreover, the general principles of designing gold NP-based colorimetric probes are also presented through (non)covalent functionalization with bioinspired DNA, oligopeptide/protein and a variety of (bio)molecules referred to colloid chemistry, surface chemistry, and coordination chemistry. All in all, valuable guidelines for probe design would benefit water sensing in the future.