Development of a Dual-Shelled pH-Responsive Polymer-MOF Nanocarrier for Sustained Imidacloprid Delivery and Enhanced Control of Megoura crassicauda

Nanopesticides represent cutting-edge technologies and approaches for achieving efficient and sustainable agriculture, offering an effective pathway toward developing environmentally friendly pesticides. To enhance the drug loading capacity (LC) and controlled release efficiency of metal–organic framework (MOF) carriers, this study used the amphiphilic lipid polymer 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (ammonium salt) (DSPE-PEG-NH 2 , MW 2000 Da) as a carrier to load imidacloprid (IMI) through a solvent evaporation approach, creating polymer nanoparticles (IMI-DSPE). Subsequently, zinc nitrate hexahydrate was employed as the zinc source to coordinate with amino groups on the polymer nanoparticles, forming IMI@DSPE-Zn 2+ . Using 2-methylimidazole as a ligand, IMI was further loaded onto IMI@DSPE-Zn 2+ through an in-situ growth strategy, yielding polymer–MOF nanoparticles (IMI-DSPE@ZIF-8). IMI-DSPE@ZIF-8 had an average particle size of 272.79   nm and an LC of 72.20%, with significantly improved IMI solubility and thus higher wettability on the surface of faba bean leaves. Compared to IMI-WG, the degradation rate of IMI-DSPE@ZIF-8 is reduced by 56.19%. Furthermore, IMI-DSPE@ZIF-8 exhibited a cumulative release of 84.6% at pH 5.0, which was higher than that under neutral conditions, indicating that its pH-responsive properties will enable it to respond effectively to the acidic microenvironment of aphid intestines. Compared to commercially available water-dispersible IMI granules (IMI-WG), pot experiments demonstrated the superior efficacy of IMI-DSPE@ZIF-8 in controlling M. crassicauda . The excellent insecticidal activity of IMI-DSPE@ZIF-8 against target pests, combined with its superior compatibility with non-target organisms, provide a scientific basis for reducing pesticide usage, enhancing insecticidal efficacy, and promoting green, sustainable pest control in agriculture.