Colorimetric sensing of biomarkers based on the enzyme-mimetic activity of metal nanoclusters

Metal nanoclusters (MNCs) less than 10 nm in size have emerged as exciting functional nanomaterials. As a new generation of artificial mimetic enzymes, they exhibit similar catalytic efficiency and better stability than natural enzymes, while maintaining a certain activity level in harsh conditions, such as strong acids, bases, and a wider temperature range. In this review, the synthesis approaches of MNCs are summarized and their enzyme-like properties are briefly described including peroxidase (POD)-like, oxidase (OXD)-like, catalase (CAT)-like, and superoxide dismutase (SOD)-like activities. Importantly, the applications of MNCs with mimetic enzyme activities for colorimetric sensing detection of biomarkers are also highlighted and types of colorimetric-based sensors such as smartphones, paper, and microneedles are briefly illustrated.