Self-Propelled Magnesium Microrobots With Enzyme-Encapsulated Metal-Organic Framework for Accelerated Chemical Warfare Agent Degradation in Harsh Environments.

The fast and efficient degradation of chemical warfare agents (CWA) is an unmet challenge due to the vulnerability of catalytic and biocatalytic reactions to various environmental conditions and their slow mass transfer conditions. While the phosphotriesterase (PTE) enzyme is highly efficient for CWA neutralization, its practical utility is greatly limited by its poor stability under variable environmental conditions. Furthermore, the efficiency of traditional PTE platforms relies solely on passive diffusion, resulting in slow mass transport and degradation kinetics. Here, we describe PTE-encapsulated metal-organic frameworks (MOF) particles immobilized on magnesium-based microrobots (PTE@ZIF-8 Mg microrobots) for efficient motion-based CWA degradation under harsh environmental conditions involving high temperatures and low pH. The encapsulation of PTE in zeolitic imidazolate framework-8 (ZIF-8) MOF particles greatly improve its thermal and pH stability toward the extended CWA neutralization under such extreme conditions. The PTE@ZIF-8 Mg microrobots display long-lasting propulsion behavior in harsh aqueous environments and induce significant fluid mixing, thus substantially enhance CWA degradation efficacy. Dramatic improvements in the degradation efficiency of methyl paraoxon (DMNP) and ethyl paraoxon (DENP) are observed compared to their static counterparts. Our findings pave the way for next-generation deployable enzyme-functionalized microrobots capable of fast, efficient, and robust CWA degradation.