High-specificity near-infrared fluorescent probe for chymotrypsin imaging: Innovative diagnostic tool for pancreatic diseases

Pancreatic diseases are closely linked with the abnormal activity of various proteases, including chymotrypsin. Currently, probes specifically designed for the detection of chymotrypsin in pancreatic disorders are unavailable. In this study, we developed a highly specific and sensitive fluorescent probe for the detection of chymotrypsin activity to enable precise diagnosis of pancreatic diseases. The probe was incorporated with Nile red as the fluorescent moiety and 4-bromobutanoyl as the recognition and quenching group to facilitate a "fluorescence switch" response upon enzymatic cleavage. The probe had high specificity and sensitivity to chymotrypsin, which remained unaffected in the presence of 52 biological interferents. It had a linear detection range of 0.1–0.75 μg/mL and a limit of detection of 0.0203 μg/mL, indicative of superior analytical performance. Cellular assays showed that the probe could effectively distinguish between normal pancreatic cells and tumor cells. Furthermore, the applications of the probe in pancreatitis models revealed its capability to accurately differentiate between normal tissue, chronic pancreatitis, and acute pancreatitis and to provide robust support for real-time imaging and disease progression monitoring. Subsequent in vivo experiments further validated the probe's diagnostic efficacy, highlighting its potential in the diagnosis of pancreatic diseases. These findings provide a solid foundation for developing molecular tools for early diagnosis and therapeutic monitoring of pancreatic disorders, demonstrating its significant potential in clinical diagnostics and precision medicine.