Smart controlled-release avermectin nanopesticides based on metal–organic frameworks with large pores for enhanced insecticidal efficacy

Nanopestcides based on metal–organic frameworks (MOFs) have attracted great attention. Highly stable mesoporous metal–organic framework PCN-777 with large pores can accommodate the biologically active insecticide avermectin (AVM) of relatively large molecular dimensions. In this work, PCN-777 nanoparticles were synthesized for the creation of double-gated nanopesticides with sodium lignosulfonate (SL) and chitosan. The double gatekeepers could realize excellent sealing performance to prevent premature leakage of AVM. The double-gated PCN-777 based nanopesticides could achieve the controlled release of AVM in response to pH, laccase, phosphate, and phytic acid (PA), which are related to the physiological environments of pests and crops. The PA-triggered controlled release of loaded cargos in MOF-based delivery systems was reported for the first time. This is the first example of PCN-777 drug/pesticide delivery system and also the first case of controlled-release MOF-based AVM nanopesticides, and the mechanisms of the stimuli-responsive controlled pesticide release were clearly elucidated. The nanopesticides prevented the ultraviolet photolysis of AVM owing to the PCN-777 organic ligands and SL coating. The nanopesticides had high insecticidal efficacy and field control efficacy against the pests Spodoptera litura Fabricius on cabbage, in comparison with traditional pesticide formulations, and the nanopesticides had no influence on plant growth and showed high biosafety toward non-target organisms and human cells. The smart controlled-release nanopesticides show high potential and application prospect in ecological agriculture.