Cellulose Nanocrystal/Zn-MOF Nanocarriers for Enhanced Foliar Adhesion, pH-Responsive Release, and Efficient Pesticide Delivery.

Stimuli-responsive nanopesticide delivery systems have attracted increasing attention due to their potential for controlled release and targeted application. However, their practical use in agriculture is often hindered by poor foliar retention, limited UV stability, and uncontrolled release behaviour. In this study, a grape-pedicel-like nanocarrier was constructed via in situ integration of cellulose nanocrystals (CNCs) with zeolitic imidazolate frameworks (ZnMOFs), which effectively encapsulated acetamiprid (Ace) and exhibited enhanced leaf adhesion and sustained-release performance. The release of ACE was triggered by naturally occurring organic acids (e.g., oxalic acid) generated during plant metabolism, enabling a pH-responsive behaviour under mildly acidic conditions (pH = 5). The cumulative release reached 85.9%, and the release kinetics followed the Ritger-Peppas model. Compared with commercial formulations, Ace@CNC/ZnMOFs showed superior dispersibility and significantly improved foliar adhesion (28.9 mg cm-2), as well as enhanced UV resistance (65.1%) and rainfastness (61.3%). Moreover, the nanocarriers exhibited improved insecticidal activity (LC50 = 11.9 mg/L) and reduced toxicity toward non-target organisms, such as zebrafish. Life cycle assessment (LCA) further confirmed its advantages in resource efficiency and environmental sustainability. Overall, this work presents a multifunctional nanopesticide system with stimuli responsiveness to integrate strong adhesion and compatibility, offering a promising strategy for sustainable agricultural applications.