PH and redox dual-responsive ZIF-8-based nanoplatform for targeted pathogens and environmental protection

Abstract

Environmental stimulus-responsive controlled-release nanopesticides have the ability to adapt to the specific microenvironment of pathogen outbreaks, which can improve pesticide utilization efficiency. A pH and redox dual-stimuli responsively controlled release system (ZIF-8@Hex@Fe/GA) using zeolitic imidazolate framework-8 (ZIF-8) as the support and metal-phenol complex (Fe-GA) as the capping agent was constructed to deliver hexaconazole (Hex) for management of Phomopsis sp. The ZIF-8@Hex@Fe/GA composite demonstrated a high loading capacity and effectively improved the light stability of Hex. The hydroxyl groups present in the composite facilitate its diffusion on kiwifruit leaves, improving wettability. Additionally, the large specific surface area of ZIF-8@Hex@Fe/GA provides resilience against rainwater scouring. This innovative system intelligently responds to the acidic and oxidizing conditions associated with Phomopsis sp. infections, ensuring targeted and controlled release of Hex. Bioactivity assessments revealed that ZIF-8@Hex@Fe/GA exhibited protective effects of 84.16 ± 3.37 % and 80.77 ± 2.08 % on kiwifruit fruits and leaves at a concentration of 100 mg/L, outperforming Hex emulsifiable concentrate (Hex EC) by 21.34 % and 25.39 %, respectively. The acute toxicity of ZIF-8@Hex@Fe/GA to zebrafish was reduced 9-fold compared to Hex EC. Furthermore, ZIF-8@Hex@Fe/GA showed high safety for HEK293 cells, with a cell survival rate of 81.59 ± 2.11 % after 72 h of 10 mg/L treatment, whereas the cell survival rate for Hex TC, treatment was only 1.79 ± 1.32 % after 72 h. In conclusion, ZIF-8@Hex@Fe/GA demonstrates significant potential for targeted pesticide delivery and environmental protection.