Degradable mesoporous organosilicon nanoparticles coated with chitosan-Cu2+ complexes with dual stimulus-response for efficient prochloraz delivery

Accurate pesticide application enhances efficiency, reduces usage and minimizes environmental risks. This study employed amino-functionalized degradable mesoporous organosilicon nanoparticles (DMON-N) as a carrier, with chitosan (CS) acting as a capping agent. Chemical cross-linking of CS with Cu 2+ through chelation promotes the formation of Cu 2+ -CS complexes. A pH/redox dual-responsive prochloraz (PRO) delivery system (Cu-CS@PRO-DMON, CCPD) was constructed and evaluated for its potential application in controlling rice sheath blight. The successful preparation of CCPD was confirmed through a series of physicochemical characterizations. The findings demonstrated that CCPD exhibited a high PRO loading capacity (29.09 %) and that PRO could be released from CCPD for an extended duration (up to 144 h) under the influence of acidity and glutathione promotion. Furthermore, CCPD demonstrated excellent wettability (measured contact angle: 63.52 ± 0.42°), adhesion (23.83 ± 2.59 mg/cm 2 ) and resistance to rainfall washout on rice leaves. CCPD demonstrated superior antimicrobial efficacy to prochloraz technical (PRO TC) material and prochloraz emulsion in water (PRO EW). The biosafety assessment revealed that CCPD exhibited minimal acute toxicity to zebrafish, no discernible toxicological effects on human bronchial epithelial cells and no notable impact on rice.