Functionalized <scp> Fe ₃ O ₄ </scp> nanoparticles for mitigating drought and disease in crops and reducing non‐target biotoxicity

BACKGROUND: ) nanoparticles are modified with L-arginine (Arg) and grafted with cinnamaldehyde (Cin) to prepare smart Fe-Arg-Cin nanoparticles (NPs) for alleviating drought and disease stresses. RESULTS: The structure and properties of Fe-Arg-Cin were characterized. Results revealed that the nanoparticles exhibit a uniform size distribution with 6.8% Cin loading. Fe-Arg-Cin NPs can effectively mitigate the inhibitory effects of drought stress on seed germination and seedling growth for rice and wheat. In addition, the in vitro and in vivo antifungal assays demonstrated that Fe-Arg-Cin NPs has potent antifungal activity against rice sheath blight (Rhizoctonia solani) and wheat sharp eyespot (Rhizoctonia cerealis). Moreover, biosafety evaluation showed that compared with Cin treatment, Fe-Arg-Cin NPs treatment remarkably reduces toxicity to zebrafish, human liver cells and soil microbial communities. CONCLUSION: The Fe-Arg-Cin NPs could not only improve the resistance of rice and wheat to drought stress and enhance the control effect against agricultural pathogens, but also ensures safety for non-target organisms. This platform provides a promising strategy for improving crop resistance under drought and disease conditions. © 2026 Society of Chemical Industry.