Selective detection of glutathione based on the recovered fluorescence of BSA-AuNCs/Cu2+ system

A bovine serum albumin-stabilised gold nanoclusters/Cu 2+ (BSA-Au NCs/Cu 2+ ) system was constructed as a fluorescent sensor for the ‘off–on’ detection of glutathione (GSH). The fluorescence of BSA-Au NCs could be effectively quenched by Cu 2+ due to the strong affinity between BSA-Au NCs and Cu 2+ . Then, coordination of Cu 2+ to GSH enabled the recovery of the fluorescence of BSA-Au NCs. To assess the selectivity of the BSA-Au NCs/Cu 2+ for GSH, K + , Mg 2+ , Ca 2+ , glucose, cysteine, tryptophan, and phenylalanine were examined under identical conditions, and all of them did not induce noticeable responses to BSA-Au NCs/Cu 2+ except for Cys. There was a good linear dependence of fluorescence intensity on the concentration of GSH in the range of 0.4–20.0 μM with the detection limit of 0.36 μM. The proposed sensor showed excellent performance in the selective detection of GSH.