Acetylcholinesterase-capped mesoporous silica gated switches for selective detection of high-toxicity organophosphate compounds

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Organophosphate (OP) compounds are widely used in agriculture, industry, and even terrorism. It is important to distinguish high-toxicity OP compounds from low-toxicity OP compounds in dealing with chemical accidents. However, there are very few portable and simple detection methods. Mesoporous silica gated switches may provide an effective solution. In this study, a gated switch based on mesoporous silica as an inorganic scaffold loaded with sulforhodamine B and capped with acetylcholinesterase (AChE) was prepared for specific detection of OP compounds. Carbamate derivatives (G1–G6) were designed and synthetized as grafting compounds in consideration of the binding ability with AChE. Through further modification and optimization, grafting compound G6 with phenylpyridine as the substituent showed the best capping capacity, and it achieved excellent blocking of mesoporous silica gated switches for loaded sulforhodamine B. In the presence of high-toxicity OP compounds, low-toxicity OP compounds, AChE substrates and reversible AChE inhibitors respectively, only high-toxicity OP compounds could make the gated switch release loaded sulforhodamine B. The limit of detection for paraoxon-ethyl was 10.6 μΜ. Furthermore, the preparation process of the gated switch is fast and simple, and the prepared gated switch has good stability and rapid distinguishing ability. The results of this paper provide a new idea for rapidly distinguishing high-toxicity OP compounds from low-toxicity OP compounds and other related compounds on the spot.