沸石咪唑酸酯骨架-8负载二氯吡啶酸纳米载药体系制备及性能研究

    Preparation and performance study of zeolitic imidazolate frameworks-8 loaded clopyralid nanoparticle drug delivery system

    • 摘要: 二氯吡啶酸是一种激素型杂环类除草剂,已被广泛用于防治油菜、玉米、小麦等田间的阔叶杂草。由于二氯吡啶酸可溶于水且容易移动,目前已被认定为农业废水中一种重要的新型污染物。将二氯吡啶酸制备成缓控释剂型有望降低其对环境的负面影响。本研究以沸石咪唑酸酯骨架-8 (ZIF-8) 作为载体材料制备了二氯吡啶酸@ ZIF-8纳米载药体系,并对负载方法进行了优化以提高载药量,通过透射电镜、动态光散射、X射线衍射、傅里叶变换红外光谱、热重分析、N2吸附-脱附对其形貌、粒径分布、化学官能团、晶体结构、热稳定性等指标进行了表征,并研究了其释放机制与除草活性。结果表明:二氯吡啶酸可成功负载到ZIF-8载体中,载药后粒径约为219.3 nm,载药量最高可达43.6%,其释放模式最符合Weibull模型 (R2 = 0.9999)。生物活性测定表明,将二氯吡啶酸负载到ZIF-8后不会降低其对稗草的除草活性,甚至在高浓度下,ZIF-8负载还能起到一定的增效作用。本研究可为基于ZIF-8载体的除草剂载药体系制备提供参考。

       

      Abstract: Clopyralid is a hormone-type heterocyclic herbicide that has been widely used to control broad-leaved weeds in crops such as rapeseed, corn, and wheat. However, clopyralid is water soluble and mobile, and it has been recognized as a new type of pollutant in agricultural wastewater. The preparation of sustained-release formulations of clopyralid can effectively reduce its negative impact on the environment. This study prepared a clopyralid loading system using zeolitic imidazolate frameworks-8 (ZIF-8) as a carrier and optimized the loading method. The morphology, size distribution, chemical functional groups, crystal structure, thermal stability and other indicators were characterized by transmission electron microscopy, dynamic light scattering, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and N2 adsorption desorption. The release mechanism and herbicidal activity were also studied. The results showed that clopyralid could be successfully loaded into the ZIF-8 carrier, with the particle size being approximately 219.3 nm after loading with clopyralid. The drug loading rate reached a maximum of 43.6%, and its release mode was most consistent with the Weibull model (R2=0.9999). Additionally, the results of bioactivity experiment against Echinochloa crus-galli showed that the herbicidal activity of clopyralid was not reduced after loading into ZIF-8, and even at a high concentration, ZIF-8 could play a certain synergistic effect. This study provided a reference for the preparation of herbicide loading systems based on ZIF-8 carrier.

       

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