金属-多酚配合物负载型杀虫微胶囊的成囊机制、释放及杀虫活性调控

Exploration of new pesticide formulations with controlled release characteristic and advanced processing technology is significant for promoting pesticide utilization as well as reducing its side effect. The membrane materials prepared by a coordination assembly between Fe3+ and tannic acid have shown favorable prospect in pharmaceutical and food industry, but no any reports in pesticide. In this research, insecticide-carried microcapsules of different characteristics will be prepared with chelates as wall material. In order find the mechanism of encapsulation, two typical insecticides of different physicochemical properties will be selected as models and the encapsulation efficiency by different chelates, made by changing type of metal and polyphenolsa including Fe3+ and tannic acid, will be compared. The degradation of different chelates, the release kinetics and the stability of insecticide microcpsule under different application circumstances will be studied. On the basis, the effect of encapsulation on the bio-efficacy and persistence to several target insects will also be evaluated. All the results will make a comprehensive evaluation on the potentials of metal-polyphenol chelates as wall material for the encapsulation of insecticide. We expect to find the key preparation factors and environment factors of affecting the releasing characteristic and bio-efficacy.

探索释放受控的新剂型及技术是提高农药利用率，降低副作用的重要手段，安全、性能优良的载体材料和简单易控的制备方法则是实现该目标的关键。符合该特征的以铁和单宁酸配合物自组装膜材料在医药、食品领域已展现出良好的应用前景，但在农药领域尚未见报道。本项目拟利用三价铁等金属离子与单宁酸等多酚化合物配位反应生成的配合物材料为壁材，制备不同特征的两种典型杀虫剂的微胶囊，比较不同配合物囊壁材料对不同理化性质农药的包覆效率，初步探索其成囊机制；研究微胶囊在不同环境条件下的稳定性及影响因素；研究不同特征参数载药微胶囊的释放动力学，明确微胶囊化对杀虫剂不同作用方式毒力和残留毒效的影响。目的是初步明确配合物材料制备农药微胶囊的可行性并确定其实现方法，初步了解影响释放和杀虫活性的关键制备因素和环境因素。

基于现有农药品种，通过剂型改造和施药技术改进以提高利用率是当前农药研究的重要方向之一。本项目初步阐明了金属-多酚配合物负载型微胶囊的成囊机制，了解了不同配合物材料包覆农药时的性能差异；包覆了毒死蜱、辛硫磷、吡唑醚菌酯、溶剂油等一系列化学品，拓展了金属-多酚配合物负载型微胶囊的适用范围。以Fe3+和单宁酸为单体制备了毒死蜱微囊，基于响应面法，采用五因素五水平的中心复合设计研究了单宁酸的滴加速率和浓度，Fe3+的滴加速率和浓度，反应温度对微胶囊包覆率和释放性能的影响，明确了微胶囊制备工艺优化途径，建立了成熟的制备方法。采用AFM表征了吡唑醚菌酯微胶囊的形貌、厚度；采用FTIR，EDS，XPS明确了微胶囊的囊壁材料组成、元素组成。通过田间药效试验明确了吡唑醚菌酯微胶囊控制水稻稻瘟病的优异性，证明微囊化处理可以有效降低吡唑醚菌酯对水生生物毒性；初步明确了微胶囊特征参数与释放和毒效/毒性的定量关系，初步明确了金属-多酚配合物载药微胶囊的释放机制及调控途径。设计了微胶囊溶出试验所用的新型装置；开发了检测微胶囊释放的新方法，该法检测毒死蜱、辛硫磷、吡唑醚菌酯和异噁草松微胶囊具有良好的稳定性；可用于检测以配位化合物、聚脲、聚氨酯、脲醛树脂等为囊壁的微胶囊产品。此外，通过与最常用的透析袋法对比发现，该方法在装置简便性，释放介质用量，精密度方面均有一定的优势。