Enzyme Mimics of Bimetallic Nanoclusters for Detection of Trypsin

Detection of trypsin is crucial for human health. In this work, bovine serum albumin-protected osmium-silver nanoclusters were prepared. The silver content in the nanoclusters could be regulated by controlling the reagent concentration. Ultraviolet-visible absorption spectra of 3,3',5,5'-tetramethylbenzidine and its oxidized form were used to investigate the catalytic activity of the nanoclusters. All nanoclusters displayed peroxidase-like activity. Especially, the bovine serum albumin-protected osmium-silver nanoclusters with 20% silver content showed the highest catalytic activity. In addition, trypsin effectively increased the catalytic activity of bovine serum albumin-protected osmium-silver nanoclusters due to the interaction between trypsin and bovine serum albumin. Based on this phenomenon, a novel method for selective detection of trypsin was developed with a limit of detection of 5 ng/mL. This method shows promise for the detection of trypsin in fetal bovine serum with an acceptable recovery rate.