PNNL

Abstract

The detoxification of lethal organophosphate (OPs) residue in the environment is crucial to prevent human exposure and protect modern society. Despite serving as excellent catalysts for OP degradation, natural enzymes require costly preparation and readily deactivate upon exposure to environmental conditions. Herein, we designed and prepared a series of phosphotriesterase mimics based on stable, self-assembled peptoid membranes to overcome these limitations of the enzymes, and effectively catalyze the hydrolysis of dimethyl p-nitrophenyl phosphate (DMNP) – a nerve agent simulant. By covalently attaching metal-binding ligands into peptoid N-termini, we attained enzyme mimetics in the form of surface-functionalized crystalline nanomembranes. These nanomembranes display a precisely controlled arrangement of coordinated metal ions, which resemble to the active sites found in phosphotriesterases to promote DMNP hydrolysis. Moreover, using these highly programable peptoid nanomembranes allows for tuning the local chemical environment of the coordinated metal ion to achieve enhanced hydrolysis activity. Among the crystalline membranes that are active for DMNP degradation, those assembled from peptoids containing bis-quinoline ligands with an adjacent phenyl side chain showed the highest hydrolytic activity with 219-fold rate acceleration over the background, demonstrating the important role of the hydrophobic environment in proximity to the active sites. Furthermore, these membranes exhibited remarkable stability and were able to retain their catalytic activity after heating to 60oC and after multiple uses. This work shed light insights into the principal features to construct a new class of biomimetic materials with high catalytic efficiency, cost-effectiveness and reusability applied in nerve agent detoxification.