A Facile and Safe Route to Fabricate Boscalid-Loaded ZIF-8 Nanoparticles With Efficient Antibacterial Activity and Long-Sustained Release

Abstract

Synthesis of ZIF-8 mainly uses zinc nitrate hexahydrate (Zn(NO₃)₂.6H₂O) as the zinc source. Zn (NO₃)₂.6H₂O is flammable, explosive, and highly corrosive, posing a threat to human health. It also requires a molar ratio of 2-methylimidazole to zinc source greater than 20, resulting in increased costs. In this work, a pH-sensitive controlled-release nano-capsule of fungicide, ZIF-8@Boscalid, was established using green zinc sources (zinc sulfate and zinc acetate) and was prepared based on metal–organic framework (ZIF-8) for higher antifungal effect and low bio-toxicity. The loading ratio is as high as 34%. In addition, the release of fungicide Boscalid showed pH-sensitive response due to the weak acidic group in the ZIF structure, in which the rate of release was more rapid under acid condition (< 5). Cumulative release rates of the ZIF-8(A)@Boscalid system and ZIF-8(S)@Boscalid system were 76.15% and 86.22%, respectively. Meanwhile, the antifungal effect of ZIF-8@Boscalid was 1.5 times more of that commercially available product on CI-8 at the concentration of 300 mg/L, and the antibacterial activity values of the ZIF-8(A)@Boscalid system and ZIF-8(S)@Boscalid system against CJ-8 were 84.54% and 78.65%, respectively. Furthermore, the obtained ZIF-8@Boscalid system using the method described in this article exhibited certain UV resistance. Thus, this work not only proves that ZIF-8@Boscalid could be used as nanoparticles platform for smart control over CJ-8 but also has great potential effective utilization of Boscalid and achieving sustained release.