Bacterial microcompartment-mimicking Pickering emulsion droplets for detoxification of chemical threats under sweet conditions

Abstract

AbstractChemical warfare agents represent a severe threat to mankind and their efficient decontamination is a global necessity. However, traditional disposal strategies have limitations, including high energy consumption, use of aggressive reagents and generation of toxic byproducts. Here, inspired by the compartmentalized architecture and detoxification mechanism of bacterial micro-compartments, we constructed oil-in-water Pickering emulsion droplets stabilized by hydrogen-bonded organic framework immobilized cascade enzymes for decontaminating mustard gas simulant (2-chloroethyl ethyl sulfide, CEES) under sweet conditions. Two exemplified droplet systems were developed with two-enzyme (glucose oxidase/chloroperoxidase) and three-enzyme (invertase/glucose oxidase/chloroperoxidase) cascades, both achieving over 6-fold enhancement in decontamination efficiency compared with free enzymes and >99% selectivity towards non-toxic sulfoxide. We found that the favored mass transfer of sugars and CEES from their respective phases to approach the cascade enzymes located at the droplet surface and the facilitated substrate channeling between proximally immobilized enzymes were key factors in augmenting the decontamination efficacy. More importantly, the robustness of immobilized enzymes enabled easy reproduction of both the droplet formation and detoxification performance over 10 cycles, following long-term storage and in far-field locations.