A novel strategy for sensitive detection of thrombin via subtly integrated polypeptide substrate and aggregation-induced emission fluorophores in carotid artery thrombosis

Accurate monitoring thrombin played an important role in the diagnosis of carotid artery thrombosis. In this investigation, a novel strategy was designed by one-step process for sensitive and specific detection of thrombin via integrated 2-(4-bromophenyl)− 3-(4-(4-(diphenylamino)styryl) phenyl) fumaronitrile (TPABDFN) and polypeptide substrate. More concretely, TPABDFN was gathered and wrapped by the peculiar short chain polypeptide substrate (SPS) with the assistance of glutaric dialdehyde in water containing 10 % tetrahydrofuran (THF), possessing an “ON” state owing to the aggregation-induced emission (AIE) characteristics. In the present of thrombin, the TPABDFN-SPS could be specifically degraded, leading the “OFF” state by the specific hydrolysis of thrombin. Indeed, the fluorescence intensity of the TPABDFN-SPS would decline with the increasing concentrations of thrombin. The results demonstrated that this “turn-off” fluorescent complex had a linear response in the range of 1.56–200 ng mL−1 for thrombin with the detection limit of 0.42 ng mL−1. More fascinatingly, this strategy could further applied to monitor thrombin in the plasma sample, which displayed that the thrombin concentration in the plasma of carotid artery thrombosis (CAT) rats was higher than that in the sham group. Conceivably, the proposed strategy showed prospective promise in the detection of target proteases for the diagnose of certain disease.