A Bioinspired, Photostable, Rain-Resilient Zein-Polyphenol-Based Nanocomposite with Enhanced Pesticidal Activity for Sustainable Agrochemical Delivery

Abstract Conventional pesticide formulations suffer from poor foliage retention, rapid photodegradation, and the need for repeated applications, thereby reducing field efficacy and increasing environmental burden. Herein, we designed a water-dispersible, bioinspired nanopesticide (IND@PLA@PZTA) by coating indoxacarb-loaded poly(lactic acid) nanoparticles with a phosphorylated zein–tannic acid coating. The formulation achieved 96.3% encapsulation efficacy and sustained pesticide release for 96 h while exhibiting improved wettability, foliage retention, and enhanced UV protection, retaining 72% of the pesticide after 3 h of UV exposure. Against Spodoptera litura, the nanopesticides produced 96.7% larval mortality after 56 h, representing a 2.6-fold improvement over the commercial formulation, and effectively suppressed larval development. A greenhouse study further validated these results. Moreover, the nanoformulation also showed reduced toxicity toward nontarget organisms, including ladybirds, soil bacteria, Daphnia magna, Vigna radiata and human keratinocytes. Constructed entirely from Generally Recognized as Safe (GRAS) materials, this multifunctional nanopesticide represents a sustainable strategy for pesticide delivery.