Copper Ion-Chelated and Polydopamine-Modified Hydroxypropyl Methylcellulose Nanoparticles with Multiple Responses for...

Intelligent controlled-release nanopesticides have been a crucial tactic in advanced precision agriculture during the past few years, which can improve pesticide utilization and reduce environmental pollution. Herein, a novel hydroxypropyl methylcellulose-based nanopesticide carrier (PCH) with pH-/enzyme-/near-infrared multiple responses was constructed by the initial cross-linking with dimethyl diallyl ammonium chloride and the subsequent copper ion chelation and polydopamine coating. Avermectin (Av) was further loaded to create the intelligent pesticide release system (APCH) by antisolvent precipitation. The release of APCH increases under near-infrared light (NIR) conditions, with an accumulative release that is 3.26 times higher than that without NIR. The contact angles of APCH on cabbage leaves are 33 and 29% lower than those of water and technical Av (Av-tech), respectively, verifying that APCH has a good wettability property. Simultaneously, APCH displays better insecticidal activity than Av formulations because of its outstanding ultraviolet (UV) light stability of Av. The degradation rate of Av in APCH is less than 2% in 50 h under UV light, which is considerably lower than that of Av-tech (∼60%). The biosafety assessments manifest that the PCH carrier has remarkable biological safety on the growth of nontarget organisms in a certain range. Overall, the APCH system is bio-friendly with multiple-response release behaviors, excellent UV light stability, and foliar deposition performance, which can offer a new strategy for sustainable agricultural development.