Zein-Sodium Caseinate Composite Nanoparticle-Stabilized Pickering Emulsion for Controlled Pesticide Delivery

Traditional pesticides suffer from low utilization rates, poor photodegradability, and environmental pollution issues. Developing highly efficient and environmentally friendly pesticide delivery systems is of paramount importance. This study utilized zein-sodium caseinate (Zein-NaCas) composite nanoparticles as stabilizers with ethyl acetate (EA) and soybean oil (SO) as the oil phase. Without the addition of toxic surfactants, the hydrophobic pesticide avermectin-loaded Pickering emulsion (AVM@PK) was prepared. Zein-NaCas solid particles were formed through hydrophilic–hydrophobic interactions and can adsorb at the oil–water interface to form a boundary film, thereby preventing droplet coalescence. By optimizing the solid particle concentration and oil phase volume fraction, this system maintains excellent emulsion stability. Compared with AVM-commercial emulsified oil (AVM-EC), this emulsion exhibits 2.1-fold enhanced photodegradation resistance. In vitro release experiments indicate that glutathione (GSH) degradation rapidly destabilizes the emulsion, leading to accelerated avermectin (AVM) release. Bioactivity tests demonstrate that the emulsion exhibits higher lethality and lower LC 50 values against lepidoptera insects. This study provides a novel strategy for constructing green pesticide delivery systems and achieving efficient encapsulation and slow release of hydrophobic pesticides.