Recent Advances in the Synthesis, Properties, and Biological Applications of Platinum Nanoclusters

Abstract

Noble metal nanoclusters (M NCs), defined as an aggregation of a few to tens of atoms, are considered a borderline between atoms and metal nanoparticles (M NPs), which tends to exhibit molecule-like behaviours such as discrete electronic state and size-dependent fluorescence. In the past decades, gold and silver nanoclusters (Au NCs and Ag NCs) have been massively explored and utilized in the field of industrial catalysis, optoelectronic devices, biological imaging, environmental detection, clinical diagnoses, and treatment. The analogue of Au and Ag NCs and platinum nanoclusters (Pt NCs), especially their biological applications, is relatively and rarely discussed. This review firstly investigates the synthetic methodology of Pt NCs including template-assisted and template-free approaches and then introduces their unique optical, catalytic, and thermal properties. Particular importance here is the biological applications of Pt NCs such as the bioimaging of various cells as a preferred fluorophore in contrast to traditional fluorescent markers (e.g., organic dye, semiconductor quantum dots, and fluorescent proteins), the usage of Pt NCs-based antitumour drugs as a new class chemotherapeutics for malignant tumour therapy, and the utilization of antibacteria as an alternative of Ag-based antibacterial agent. On the whole, the development of Pt NCs has already gained delectable progress; however, the study of ultrafine Pt NCs is at the beginning stage and there are still plenty of challenges like synthesis of near-infrared (NIR) fluorescent Pt NCs, the explicit signal pathway of cell apoptosis, and attempt in diverse biological applications that need to be urgently tackled in future.