Enzyme mimics of bimetallic nanoclusters for detection of trypsin

Detection of trypsin is very important for human health. In this work, bovine serum albumin protected OsAg nanoclusters (BSA-OsAg NCs) were prepared. The ratio of Ag element in the nanoclusters could be regulated by controlling the reagent concentration. UV-Visible absorption spectra acquired from TMB(3,3',5,5'-Tetramethylbenzidine) to oxTMB were used to investigate the catalytic ability of the nanoclusters. The nanoclusters all displayed peroxidase-like activity. Especially, the BSA-OsAg NCs with 20% silver content showed the best catalytic ability. In addition, trypsin effectively increased the catalytic activity of BSA-OsAg NCs due to the interaction between trypsin and BSA. Based on this phenomenon, a novel method for selectively detection of trypsin was developed with a detection limit (LOD) of 5ng/mL. Promisingly, this method can be used for detection of trypsin in fetal bovine serum with acceptable recovery rate.