Metal Nanoclusters in Point-of-Care Sensing and Biosensing Applications

Nanoclusters are nanostructures consisting of few totens of atomswhich have attracted great interest from the scientific communitydue to their applications in a myriad of fields, from catalysis tobiomedical applications. Due to the discrete energy levels resultingfrom their ultrasmall size, nanoclusters exhibit distinctly differentchemical, optical, and electrical properties compared with their largernanoparticle counterparts. Unlike previously reported nanostructureswith larger dimensions (1-10 nm), which typically have a singleadvantage (for example, high conductivity or optical properties),nanoclusters can be used as signaling and/or reaction-acceleratingmaterials in almost all sensing assays with enhanced properties. Nanoclustersare among the most promising luminescent emitters (electrochemiluminescent,fluorescent, chemiluminescent, and colorimetry) with high quantumyield and better biocompatibility than conventional emitters. Consideringtheir excelent biocompatibility, tailored modification, and desirableelectrochemical and optical tunability, nanoclusters have opened newhorizons in designing high-performance sensing and biosensing devices.In addition, they represent excellent electrochemical and photoelectrochemicalbehaviors with improved functionality and environmentally friendlyproperties compared to traditional compounds. This review discussesthe recent advances in nanoclusters, their applications in sensingand biosensing, current limitations, and prospects to overcome thesechallenges. The present study gives a much brighter vision of nanoclustersthat discusses one by one their particular advantages and role indeveloping sensing frameworks.