Protein-Protected Water-Soluble Platinum Nanoclusters as Fluorescent Probe for Trypsin Detection

Trypsin, as a key serine protease, is one of the most important digestive enzymes. It plays a significant role not only in the digestive process but also serves as an important biomarker for diseases such as acute pancreatitis, cystic fibrosis, and cancer based on its expression level. Therefore, developing a trypsin detection method with high sensitivity, rapid response, and simple operation holds significant research value. In this study, ultrasmall platinum nanoclusters (PtNCs@HSA) were synthesized using human serum albumin as a template and applied for trypsin detection. Human serum albumin can act as a substrate for trypsin, and the prepared platinum nanocluster probes exhibit excellent fluorescence properties, displaying blue fluorescence at an excitation wavelength of 380 nm and an emission wavelength of 460 nm. In the presence of trypsin, the structure of the human serum albumin template within the probes is disrupted, leading to fluorescence quenching and enabling highly sensitive detection of trypsin. This method demonstrates a stable linear detection performance for trypsin within the range of 0.01–100 μg/mL and shows good applicability in urine samples from healthy volunteers, with recovery rates ranging from 92.0% to 99.6%. This study offers a strategy for developing convenient and sensitive trypsin detection tools, which holds promise for active roles in clinical diagnosis, disease screening, and monitoring.