Enzymatically degradable pesticide microcapsules fabricated from zein nanoparticle-stabilized Pickering emulsions for enhanced safety and prolonged crop protection

The extensive use of conventional pesticide formulations poses potential environmental risks, highlighting an urgent need for eco-friendly alternatives. Pesticide microencapsulation has emerged as a promising approach to reduce application frequency and minimize environmental harm, owing to its high encapsulation efficiency and sustained-release capabilities. We developed an enzymatically degradable microcapsule using Pickering emulsion templates stabilized by sodium caseinate/zein composite protein nanoparticles (PNPs) with an average size of approximately 204 nm. Notably, the cross-linked PNP-based microcapsules exhibited a pesticide loading efficiency exceeding 74 %, high stability, and enabled accelerated release under enzyme-rich conditions. Field trials demonstrated that the degradable microcapsules provided time-dependent pest control, with efficacy improving from 67 % on day 2 to 83 % on day 15. In contrast, a commercial microemulsion showed rapidly declining effectiveness after the second day. These results underscore the ability of the microcapsules to extend the duration of pest management, despite slightly reduced initial activity. Furthermore, the encapsulation strategy markedly improved safety toward non-target organisms, exhibiting markedly lower adverse impacts on seed germination, zebrafish, and earthworms relative to commercial formulations. Importantly, the protein nanoparticle-based Pickering emulsion platform demonstrated broad applicability, enabling the successful encapsulation of various pesticide compounds.