Ultrasmall metal nanoclusters for bio-related applications

The study of ultrasmall metal nanoclusters (NCs, ranging from subnanometer to ca 2 nm) is evidently a quickly evolving field in current nanoscience and nanotechnology research. Metal NCs, typically composed of several to hundreds of metal atoms, have attracted great interest in recent years owing to their unique properties including ultrasmall size and enhanced photoluminescence, together with other properties such as excellent photostability, low toxicity, and good biocompatibility desired for biological applications. This review summarizes recent advances in the field of bio-related applications of metal NCs materials. We highlight the applications of metal NCs for biosensor development, fluorescent biological imaging, and biomedical research, and finally discuss briefly some current challenges and future work.