Bioadhesive and pH-Responsive ZnO@Polydopamine Core–Shell Nanocarriers for Intelligent Pesticide Delivery and Synergistic Antifungal Action

The development of intelligent nanocarriers capable of overcoming the intrinsic limitations of conventional pesticides, including poor foliar adhesion, photodegradation, and nonspecific release, remains a major challenge in agrochemical science. Herein, we report a multifunctional core-shell nanocarrier (Pro@ZnO@PDA, denoted as PZP NPs) constructed via interfacial engineering, in which prochloraz-loaded ZnO nanoparticles (ZnO NPs) are encapsulated within a polydopamine (PDA) shell. The rough surface of the ZnO core enables a high pesticide loading capacity of 12%, while the PDA shell markedly enhances leaf adhesion, reducing the contact angle on plant leaves by 25.4%, thereby improving foliar retention. Benefiting from acid-sensitive interfacial dissociation between the PDA shell and ZnO core, the nanocarrier exhibits pH-responsive release behavior, achieving a targeted prochloraz release of 76% under acidic conditions (pH 5.4). In addition, the ZnO core effectively shields the active ingredient from ultraviolet irradiation, resulting in a 23.3-fold enhancement in photostability, whereas the PDA shell provides efficient photothermal conversion, inducing an elevation of temperature up to 38.8 °C under light exposure. The integration of controlled chemical release and photothermal effects gives rise to a synergistic antifungal mechanism, maintaining an inhibition rate exceeding 60% after 7 days of irradiation. Notably, PZP NPs exhibit bidirectional translocation within plants, addressing the limited systemic transport of conventional fungicides. This work demonstrates an interfacial-engineered, stimulus-responsive nanoplatform that offers a promising strategy for intelligent and efficient pesticide delivery.