Molecularly imprinted nanocapsule mimicking phosphotriesterase for the catalytic hydrolysis of organophosphorus pesticides.

Graphical abstract Highlights • Macro cyclic amine monomers designed for the hydrolysis of organophosphorus pesticide. • Nanocapsules prepared using the functional monomers with methyl parathion as template. • Nucleophilic attacking reaction mechanism was discussed. Abstract In this work, macro cyclic amine type of functional monomers, (4-vinylbenzyl)-1,4,7-triazacyclononane (VBTN) and 1,4-bishydroxyethyl-7-(4-vinylbenzyl)-1,4,7-triazacyclononane (VBTNOH), were synthesized to prepare enzyme-mimic molecular imprinting polymers (MIPs) nanoparticles with the hollowed morphology, which are expected to eliminate organophosphorus pesticide pollutants. The resulted MIPs show higher catalytic hydrolysis activity compared to the self-hydrolysis of substrate methyl parathion. Especially, the MIP with functional monomer containing alcohol assistant group (MIP-VBTNOH), shows the best performance, whose initial rate is 3.51 * 10−2 mM/h, 415-fold higher than substrate self-hydrolysis. Its Michaelis-Menten constant is as low as 0.87 mM. We attribute the good performance of MIP-VBTNOH to its alcohol assistant group on the funcional monomers because the alcohol OH is more nucleophilic than water. Such mechanism is confirmed by the observation of the intermediate in this catalytic process by 31P NMR spectrum. In addition, the introduce of hollowed nanocapsule morphology makes MIPs effectively absorb p-nitrophenol produced by the hydrolysis of organophosphate compounds, another pollutant needs to be eliminated. [ABSTRACT FROM AUTHOR]