Tuning Atomically Dispersed Metal Sites in Nanozymes for Sensing Applications

Nanozymes with atomically dispersed metal sites (ADzymes), especially single-atom nanozymes, have attracted widespread attention in recent years due to their unique advantages in mimicking the active sites of natural enzymes. These nanozymes not only maximize exposure of catalytic sites but also possess superior catalytic activity performance, achieving challenging catalytic reactions. These advantages position ADzymes as highly promising candidates in the field of sensing and biosensing. This review summarizes the classification and properties of ADzymes, systematically highlighting some typical regulation strategies involving central metal, coordination environment, etc., to achieve their catalytical activity, specificity, and multifunctionality. Then, we present the recent advances of ADzymes in different sensing fields, including colorimetry, fluorescence, electrochemistry, chemiluminescence, photoelectrochemistry, and electrochemiluminescence. Taking advantage of their unique catalytic performance, the resultant ADzymes show great potential in achieving the goal of sensitivity, selectivity and accuracy for the detection of various targets. Specifically, the underlying mechanisms in terms of signal amplification were discussed in detail. Finally, the current challenges and perspectives on the development of advanced ADzymes are discussed.