Rapid synthesis of fluorescent bovine serum albumin-gold nanoclusters complex for glutathione determination

A facile one-pot method for synthesis of bovine serum albumin (BSA)-gold nanoclusters (AuNCs) has been developed. The formation of BSA-AuNCs took only 30 s under mild conditions. BSA-AuNCs exhibited strong orange-yellow fluorescence, and the excitation and emission peaks were at 370 nm and 564 nm, respectively. In the process of forming BSA-AuNCs, the molecular chain of BSA has not been destroyed. Moreover, there were a large number of Au cations on the surface of BSA-AuNCs, which had strong oxidizing abilities. The reason for the ultrabright fluorescence of BSA-AuNCs was attributed to the Au(0)@Au(I)@Au(III)-ligand structure on the surface of BSA. In order to evaluate the fluorescence performance of BSA-AuNCs, BSA-AuNCs was used as a probe, realizing the sensitive and selective determination of glutathione (GSH) in a wide linear range of 0.01–0.48 μM and a detection limit of 3.3 nM. The proposed method not only offers a brand-new scheme for synthesizing BSA-AuNCs, but also provides a platform for studying the interaction between metal core and proteins. Graphical abstract: