pH-responsive ZIF-8 film-coated mesoporous silica nanoparticles for clean, targeted delivery of fungicide and environmental hazard reduction

Using advanced functional materials and technologies to construct new, efficient, and controlled-release pesticide formulations can effectively improve the target utilization of pesticides and reduce their impact on non-target organisms and the surrounding environment. Herein, we present a strategy for preparing pH-responsive nanodrug delivery systems (Pro@MSN@ZIF-8) by loading a pesticide (prochloraz) into biocompatible mesoporous silica nanoparticles (MSNs) and using acid-unstable Metal–organic frameworks (ZIF-8) as blocking agents. The results showed that Pro@MSN@ZIF-8 was able to release Pro rapidly in acidic environments, with a cumulative release rate of 92.4% at pH= 4.5 after 72 h, which was much higher than that at pH= 7.4 (39.7%). Additionally, Pro@MSN@ZIF-8 had longer-lasting fungicidal activity than Pro-technical. Safety tests showed that Pro@MSN@ZIF-8 has a low impact on non-target organisms and the surrounding environment. The EC50 of Pro@MSN@ZIF-8 nanoparticles for aquatic Daphnia magna was 4.128 mg/L, which was approximately 1.4 times that of Pro-technical (3.027 mg/L) at 96 h. Moreover, it was less harmful to the soil microbial community and human LO2 liver cells. Pro@MSN@ZIF-8 can provide small amounts of trace elements required by plants to promote crop growth without disturbing normal growth. Therefore, this study provides an effective strategy to improve the efficiency of pesticide use and reduce environmental hazards, which are required for cleaner, environmentally friendly, and more efficient agricultural production.