壳聚糖衍生物基Pickering乳液制备及噻唑膦负载效果研究OA

Pickering emulsion pesticide delivery systems exhibit common drawbacks,including low drug loading capacity,monotonous release behavior,and a lack of systematic ecological safety evaluation.To address these lim-itations,this study employed a carboxymethyl chitosan furan phenylhydrazone derivative with a Schiff base struc-ture(CMCS-Z4)as the raw material.CMCS-Z4@CaCl₂ nanoparticles were prepared via Ca²⁺ crosslinking and used as the sole stabilizer to construct a Pickering emulsion loaded with the nematicide fosthiazate.The results showed that,under optimal conditions,the nanoparticle size was 169 nm,with water and oil contact angles of 64.9° and 59.4°,respectively,demonstrating superior amphiphilicity to most unmodified polysaccharide particles.The optimal emulsion formulation,consisting of 0.5%nanoparticles and a water/oil ratio of 1∶1.5,yielded an oil-in-water emulsion with an emulsification index exceeding 86%after 24 h,along with good centrifugal stability and pH-responsive behavior.The encapsulation efficiency of fosthiazate reached 93.1%,which was considerably higher than that of conventional surfactant-stabilized emulsions and common chitosan particle systems.The cumulative release rate within 72 h was only approximately 15%,and the release rate was considerably accelerated under acidic conditions,exhibiting dual functionality through sustained and pH-responsive release.The loading system retained concentration-and time-dependent nematicidal activity against root-knot nematodes while considerably reducing the inhibitory effects on cucumber seed germination and acute toxicity to zebrafish compared with the tech-nical-grade fosthiazate.This study provides a new strategy for the high-value utilization of marine-derived chitosan derivatives in smart green pesticide delivery,offering advantages such as high drug loading efficiency,controlled release,and low ecological risk.