Dual quenching mechanism study and application for sensitive sensing acid phosphatase activity based on bimetallic Au/Ag nanoclusters with enhanced fluorescence

In this study, we synthesized Ag-doped Au/Ag nanoclusters (GSH-Au/Ag NCs) with enhanced luminescence. We conducted a comprehensive investigation into the mechanism behind KMnO 4 -induced fluorescence (FL) quenching of these bimetallic nanoclusters and, leveraging this understanding, developed a sensitive fluorescent method for determining acid phosphatase activity (ACP). The fluorescence quenching mechanism was attributed to a combination of the inner filter effect (IFE) and redox reactions. Subsequently, ascorbic acid (AA) was generated from L-ascorbic acid 2-phosphate trisodium salt (AAP), which was selectively hydrolyzed by ACP . The released AA then reduced KMnO 4 , leading to the inhibition of fluorescence quenching of GSH-Au/Ag NCs by KMnO 4 . This innovative approach exhibited higher sensitivity, with a lower limit of detection of 0.0085 U/L (S/N = 3) for ACP activity sensing. Our proposed strategy was successfully applied to analyze ACP activity in human serum samples, demonstrating promising potential for the widespread utilization of metal nanoclusters in various applications.