Hunan Agricultural Biotechnology Research Institute, Hunan Academy of Agricultural Sciences, Changsha, Hunan410125, People's Republic of China.
Key Laboratory of Integrated Pest Management in Crops, Ministry of Agriculture, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing100193, People's Republic of China.
J Agric Food Chem. 2023 Jan 25;71(3):1417-1425. doi: 10.1021/acs.jafc.2c07616. Epub 2023 Jan 11.
Nanopesticides are considered to be a novel and efficient kind of tool for controlling pests in modern agriculture. Covalent organic frameworks (COFs), with high surface areas, ordered structures, and rich functional groups for loading pesticides, are a class of promising carrier materials that can be used to develop efficient nanopesticide delivery systems. However, until now, only a strong ionic interaction between the pesticide and COF can be utilized to achieve the combination between the pesticide and COF. On the basis of this method, charged pesticide molecules are the only choice for COF-based nanopesticides, which limits the exploitation. The way to load the uncharged pesticide molecules into COF still needs to be explored. Herein, in this research, we provided a commonly mild and high-efficacy strategy for loading an uncharged pesticide molecule into COF. The herbicide cyhalofop-butyl (CB), as a neutral model pesticide molecule, was loaded into the sphere COF (SCOF, a model COF synthesized at room temperature) without any ionic interaction via the host-guest strategy. The loading capacity of CB into SCOF (CB@SCOF) was determined at 57% (w/w). Smaller CB@SCOF particles (150-200 nm) can efficiently enter the weed leaves and stems, enhancing the accumulation of the effective concentration in weeds, thus increasing herbicidal activity, in comparison to CB emulsifiable (EC, micrometer scale). Furthermore, CB@SCOF had a solubilization effect for CB in water and can improve the photostability of CB. Thus, the CB-loaded COF nanosphere showed excellent herbicidal activities against the target weeds and compared to commercial CB EC. In conclusion, this study also provides a mild and high-efficacy pesticide loading strategy for COFs. The constructed efficient delivery system and pesticide formulation containing herbicidal COF nanospheres exhibit great potential applications for controlling weeds in sustainable agriculture.
纳米农药被认为是现代农业中控制害虫的一种新颖而有效的工具。共价有机框架（COFs）具有高比表面积、有序结构和丰富的功能基团，可用于负载农药，是一类很有前途的载体材料，可以用来开发高效的纳米农药输送系统。然而，到目前为止，只有农药和 COF 之间的强离子相互作用才能被利用来实现农药和 COF 的结合。在这种方法的基础上，基于 COF 的纳米农药只能选择带电荷的农药分子，这限制了其开发。将非电荷农药分子负载到 COF 中的方法仍有待探索。在此，本研究提供了一种普遍温和且高效的策略，用于将非电荷农药分子负载到 COF 中。除草剂氰氟草丁酯（CB）作为一种中性模型农药分子，通过主客体策略，无需任何离子相互作用，就被负载到球形 COF（SCOF，一种在室温下合成的 COF 模型）中。CB 在 SCOF 中的负载量为 57%（w/w）。较小的 CB@SCOF 颗粒（150-200nm）可以有效地进入杂草的叶片和茎部，增加杂草中有效浓度的积累，从而提高除草活性，与 CB 乳剂（微米级）相比。此外，CB@SCOF 对 CB 在水中有增溶作用，可以提高 CB 的光稳定性。因此，负载 CB 的 COF 纳米球在防治目标杂草方面表现出优异的除草活性，与商用 CB EC 相比具有更好的效果。总之，本研究还为 COFs 提供了一种温和且高效的农药负载策略。构建的高效递送系统和含有除草 COF 纳米球的农药配方在可持续农业中控制杂草方面具有巨大的应用潜力。
