Magnesium-doped Zr-porphyrin MOF nanoarchitecture with pH/photo dual stimuli-responsiveness for targeted pesticides and improved biosafety.

BACKGROUND

Conventional pesticide formulations often exhibit poor utilization efficiency, rapid photodegradation, and ecological persistence, which severely limit their field efficacy. Herein, we report a dual pH/light stimuli-responsive delivery system based on magnesium-doped zirconium-porphyrin metal-organic frameworks (MOFs) for the targeted control of rice sheath blight (Rhizoctonia solani).

RESULTS

The trifluoroacetic acid-mediated synthesis yielded uniform PCN-222 nanoparticles (⁓140 nm), while subsequent Mg2+ doping and polydopamine-assisted prochloraz (Pro) encapsulation produced functional PCN-222(Mg)@Pro@PDA architectures with high loading capacity (21.08%) and mesoporous structure. Mg-N coordination modulated the porphyrinic electronic configuration, facilitating charge separation and enhancing light-driven reactive oxygen species generation. The formulation exhibited first-order release kinetics, with accelerated liberation (74.1% after 24 h) under acidic microenvironments (pH 5.0). Compared to the commercial Pro-EC, the nanoformulation achieved a 23% reduction in leaf contact angle, approximately 3.1-fold improvement in rainfastness, and 38.5% lower EC₅₀ against R. solani. Biosafety evaluations revealed higher zebrafish LC₅₀ (4.08 mg L⁻¹) and > 95% rice germination, confirming reduced ecotoxicity and phytotoxicity.

CONCLUSIONS

This study presents a sustainable nano-agrochemical strategy that integrates precise pathogen control with environmental protection, offering a promising direction for the next generation of intelligent pesticide delivery systems.