Hydroxyl radical-induced etching of glutathione-capped gold nanoparticles to oligomeric AuI–thiolate complexes†
Abstract
Thiol-induced core etching of gold nanoparticles is a general method for the production of gold nanoclusters (AuNCs) of various sizes. This paper is the first report on the efficient reaction of glutathione-capped gold nanoparticles (GSH-AuNPs) with hydroxyl radicals to produce oligomeric AuI–thiolate complexes at ambient temperature. Also, hydroxyl radicals can etch commercially available gold nanoparticles (100 nm); this strategy can be applied for the removal of gold from scrap electronics. Additionally, proteins can trigger the aggregation of oligomeric AuI–thiolate complexes under neutral conditions resulting in the formation of fluorescent AuNCs. For example, the reaction of trypsin, lysozyme, and glucose oxidase with oligomeric AuI–thiolate complexes produces Au5, Au8, and Au13 clusters with emission maxima at 415, 460, and 535 nm, respectively. Interestingly, trypsin- and glucose oxidase-stabilized AuNCs could sense GSH and glucose via GSH-induced etching of AuNCs and H2O2-mediated oxidation of AuNCs, respectively.