A pH-responsive MOFs@MPN nanocarrier with enhancing antifungal activity for sustainable controlling myclobutanil release

The pH-responsive metal–organic framework (MOF) nanocarriers for sustainable controlled release of pesticides is promising in agricultural production owing to their long duration, high loading efficiency and antimicrobial activity. In this work, myclobutanil (MYC) was loaded into an Ag-based MOF (Ag-TCPP), and modified with a metal-phenolic network (MPN) via in-situ polymerization to construct a pH-responsive nano-delivery system (Ag-TCPP@MYC@MPN). Ag-TCPP@MYC@MPN presented a disordered nanoflower structure and many active sites with potential enhanced loading activity. The cumulative release rates of nanoparticles at pH 4.96, 7.5, and 8.5 were 52.6 %, 62.6 % and 80.0 %, respectively. Hence, Ag-TCPP@MYC@MPN has slow release rate and pH responsiveness. The antifungal activity of Ag-TCPP@MYC@MPN was significantly enhanced, and the bacteriostatic rate reached 81.8 %. This enhancement may be attributed to the synergistic antibacterial effect between tannic acid and Ag + . Safety experiments showed the nanoparticles had no inhibitory effect on the germination of Pakchoi seeds, and the pesticide residues of Ag-TCPP@MYC@MPN did not exceed the food safety standards. This work offers a new potential to develop improved responsive stimulus nanocarriers for sustainable controlled release of MYC.