Compact fiber sensor for rapid trypsin detection based on the whispering gallery mode with a liquid crystal microdroplet

Trypsin, a protease produced in the pancreas, plays a crucial role in various medical conditions, including acute pancreatitis, cystic fibrosis, and malnutrition, where abnormal trypsin levels are often implicated. Consequently, trypsin detection has emerged as a valuable diagnostic tool in clinical medicine. In this study, we introduced an integrated fiber sensor that capitalizes on the amplification and transduction capabilities of liquid crystals, coupled with the high sensitivity of the whispering gallery mode, to achieve precise trypsin detection. This innovative approach offers consecutive measurement and rapid response times , typically under 200 s, and remarkably low sample consumption, as little as 3 nL, potential for detection in capillary blood sampling. Furthermore, when subjected to validation tests for trypsin detection in human serum, our method demonstrated excellent consistency and reliability, with recovery ratios falling within the range of 97–112%. Beyond trypsin, this method's adaptability and versatility make it a universal technique with potential applications in the field of biosensing and biochemistry.