Fluorescent metal nanoclusters: From synthesis to applications

• Synthesis and bioconjugation of fluorescent metal nanoclusters (NCs) (Ag, Au, Cu, Pt).
• Fluorescent metal NCs probe metal ions, small molecules, and nucleic acids.
• We include use of fluorescent metal NCs for protein detection.
• We review use of metal NCs in cellular and in-vivo targeting and imaging.
• We envision the prospects for research on fluorescent metal NCs in the future.

Fluorescent metal nanoclusters (NCs) are a class of emerging fluorescent materials. They have excellent photostability and biocompatibility with sub-nanometer size and are easy to synthesize. Taking advantage of these features, fluorescent metal NCs have been involved in exciting developments of analytical methods for fluorescent biosensing and bioimaging. In this review, we first summarize the approaches to synthesis and bioconjugation for fluorescent metal NCs (Ag, Au, Cu and Pt). We then highlight their applications as fluorescent probes for metal ions, small molecules, nucleic acids, and protein detection. We also summarize the use of metal NCs in cellular and in-vivo targeting and imaging. Finally, we envision the various prospects for research on fluorescent metal NCs in the future.