Fluorescent Metal Nanoclusters for Detecting Small Molecules

Fluorescent metal nanoclusters (MNCs), and especially the group IB (Au/Ag/Cu) metals and their alloys, are promising materials for detecting small molecules in clinical diagnostics and biochemical analysis. Their unique fluorescence properties, size-dependent emission, strong luminescence, photostability, and biocompatibility, make them ideal for high-performance sensors. Advances in MNC synthesis and functionalization have further improved their sensitivity as optical probes. This chapter explores the fluorescence responses of Au/Ag/Cu and their alloy clusters to different analytes, including biologically important small molecules such as amines, amino acids, enzymes, metabolites, nucleotides, and vitamins. Effective fluorescent sensors require a recognition component for specific analyte interactions and a transducer component to signal these interactions. Sensor performance is influenced by factors such as cluster size, quantum yield, and signal transduction mechanisms, which are further discussed. Finally, the chapter discusses challenges related to stability, selectivity, and performance, along with strategies to enhance detection capabilities, expand the range of detectable analytes, and promote real-world applications of fluorescent MNC-based sensors.