Dumbbell-like AuNRs/CeO2 hybrid catalyst with near-infrared boosted peroxidase-like activity for colorimetric sensing of acetylcholinesterase

Aberrant fluctuation in Acetylcholinesterase (AChE) levels can be regarded as vital biomarkers for neurotoxicity induced by organophosphorus pesticides (OPs). The performance of 3,3′,5,5′-tetramethylbenzidine (TMB) based colorimetric detection of AChE heavily relies on catalysts with superior peroxidase (POD)-like activity. Moreover, regulation of POD-like activity through external light stimulation is gradually emerging as a promising strategy. Herein, we have fabricated AuNRs/CeO 2 hybrid catalysts with dumbbell-like structures and synthetic conditions for AuNRs/CeO 2 are also optimized in this work. The combination of AuNRs and CeO 2 impart the hybrid catalysts with near-infrared (NIR) induced photothermal effect and hot-electron injection from AuNRs to CeO 2 , thereby contributing to the NIR boosted POD-like activity. Moreover, the sensitive colorimetric detection of AChE activity is facilitated by the NIR boosted POD-like activity of AuNRs/CeO 2 hybrid catalysts. The detect principle is based on the hydrolysis of Acetylthiocholine (ATCh) by AChE to generate thiocholine (TCh) with active sulfhydryl (−SH), which contributes to the inhibition of NIR boosted POD-like activity of AuNRs/CeO 2 through aggregation. The linear range is determined to be 0.5 and 2.0 U/mL, and the LOD is estimated to be 1.122 μU/mL, which is much lower than previous work. Importantly, the activity of AChE in plasma and cerebrospinal fluid from OPs poisoned rats or pralidoxime-treated rats is accurately analyzed in this work, which is crucial for the clinical diagnosis and therapy of OPs poisoning-related disease.