Photo‐Responsive Supramolecular Nanopesticides via Ternary Host—Guest Complexes of Cucurbit[8]uril/Paraquat/Azobenzene on Mesoporous Silica Nanoparticles

Controllable and on-demand delivery of nanopesticides have great potential to enhance pesticide utilization and facilitate sustainable agriculture. Photo-responsive supramolecular host-guest systems capped on mesoporous nanomaterials are deemed as competitive nanovalves for efficient and straightforward control of pesticide release. Herein, azobenzene-modified mesoporous silica nanoparticles (Azo-MSNs) were fabricated for loading the pesticide imidacloprid (IMI) and subsequent construction of photo-responsive nanopesticides by taking advantage of the ternary host-guest complexes of cucurbit[8]uril(CB[8])/trans-Azo/paraquat (PQ) as nanovalves. UV-irradiation will open the nanovalves due to attenuated binding affinity of CB[8]/PQ/trans-Azo complexes, thus triggering the release of trapped IMI inside Azo-MSNs. In detail, MSNs-as (∼160 nm) were synthesized with a template agent and directly used to produce surface-modified Azo-MSNs-as. After template removal, the obtained Azo-MSNs were loaded with IMI to produce IMI@Azo-MSNs (35.60% pesticide loading), which were treated with CB[8]/PQ complexes to construct photo-responsive supramolecular nanopesticides IMI@CB[8]/PQ/Azo-MSNs. The supramolecular nanopesticides can achieve controllable and on-demand release of IMI upon 6 h of UV irradiation (total 51.20% vs. 87.95% during 11 h). This work offers an efficient and straightforward approach to constructing photo-responsive nanopesticides and holds significant importance for the sustainable development of modern agriculture.