PH/cellulase dual environmentally responsive nano-metal organic frameworks for targeted delivery of pesticides and improved biosafety

Abstract

Environmentally responsive pesticide nanocarriers can respond to the metabolites of pathogenic fungi as well as the soil microenvironment to achieve intelligent release of pesticides. In this work, a smart pH and cellulase dual environmentally responsive pesticide delivery system (Tebu@ZnMOFs@CMC) was constructed by combining carboxymethyl cellulose (CMC) and Zn-based metal–organic frameworks (ZnMOFs), which are loaded with tebuconazole (Tebu). Physicochemical characterization indicates the successful preparation of Tebu@ZnMOFs@CMC nanoparticles. The Tebu loading capacity was approximately 18.26%. Release simulations showed a higher cumulative release of Tebu under acidic and cellulase-promoted conditions. The surface coverage of carboxymethyl cellulose could effectively improve its spread on wheat and rice leaves. Compared with tebuconazole suspension concentrate (Tebu@SC) and tebuconazole technical, Tebu@ZnMOFs@CMC nanoparticles showed higher antifungal activity. It also had lower acute toxicity to zebrafish, Daphnia magna and earthworms, and no significant effect on wheat and rice. Thus, the dual environmentally responsive Tebu@ZnMOFs@CMC nanoparticles have great potential for achieving on-demand and targeted pesticide delivery.