A Rapid and Ultrasensitive Tetraphenylethylene-Based Probe with Aggregation-Induced Emission for Direct Detection of α-Amylase in Human Body Fluids.

α-Amylase plays a key role in the physiological cycle of the human body; its function is constantly explored and used as an important indicator of some related diseases like acute pancreatitis, acute organophosphorus pesticide poisoning, and anxiety or depression. However, currently, including the assay kit, existing methods suffer from low sensitivity and time consumption or are indirect assays that require the aid of a tool enzyme or inhibitor of competitive substrates; hence, they are not suitable for the low activity and nondestructive sensing of α-amylase in body fluids. A rapid, highly sensitive, and simple direct α-amylase determination in human body fluids is still challenging. In this work, an AIEgen-based small molecule α-amylase sensing system was first established. The probe has no emission signal in aqueous media because of its good solubility, but the insoluble AIE residues can be released after hydrolysis by α-amylase, lighting up fluorescence significantly. In this novel sensing system, the detection limit is calculated to be 0.14 U L-1 in MES buffer with a linear range of 0-45.5 U L-1, having been shortened to 3 min of test time and excellent selectivity to α-amylase compared to other proteins. Moreover, our method is successfully employed to demonstrate the applications in acute pancreatitis diagnosis and psychological stress analysis. The acquisition of this AIE-based method not only provides a simple technique for clinical diagnosis of related diseases but also has a promotional value for the food and pharmaceutical industries.