基于多巴胺修饰的介孔二氧化硅纳米颗粒的光-温度双重响应型农药释放系统

Light and temperature dual responsive pesticide release system based on mesoporous silica nanoparticles modified by dopamine

本文将具有光-温度双重响应特性的共聚物——聚7-(4-乙烯基苯氧基)-4-甲基香豆素-co-N-乙烯基己内酰胺-co-三乙二醇甲基醚甲基丙烯酸酯(PVNM)接枝到经多巴胺修饰的介孔二氧化硅(MSNs)表面,从而合成了聚合物刷MSNs-g-PVNM。利用傅里叶红外光谱、扫描电镜、热重分析和X射线光电子能谱等手段对其结构进行了表征,并系统地研究了其在不同刺激条件下的响应行为,探讨了聚合物刷对模型药物吡虫啉的负载和控释能力。结果表明,聚合物刷MSNs-g-PVNM对吡虫啉的负载率和负载效率分别可以达到9.2%和40.6%,释放率分别在20℃,365 nm和50℃,254 nm两个条件下达到最低(5.4%)和最高(52.4%)。叶片浸出实验可以证实,应用聚合物刷可以将三次淋洗后叶片上吡虫啉的损失率从25.2%降低到8.4%。因此,本聚合物刷可以通过改变光照、温度等外界条件调控吡虫啉的释放过程。

A light and temperature dual responsive copolymer,poly(7-(4-vinylbenzy-loxyl)-4-methylcoumarin-co-N vinyl caprolactam-co-tri(ethylene glycol)methyl ether methacrylate)(PVNM),was grafted on the surface of dopamine based mesoporous silica nanoparticles(MSNs).The resulting polymer brush,MSNs-g-PVNM,was characterized by FT-IR,TEM,TGA and XPS.The dual responsive behaviors of MSNs-g-PVNM were systematically studied.With imidacloprid as the model guest pesticide,the loading percentage and loading efficiency of the polymer brush were determined as 9.2%and 40.6%,respectively.The release efficiency of imidacloprid in MSNs-g-PVNM was the lowest value of 5.4%at 20℃ and 365 nm,and it reached the highest value of 52.4%at 50℃ and 254 nm.The loss percentage of imidacloprid on the leaves contained imidacloprid-loaded MSNs-g-PVNM(8.4%)was much less than that contained only imidacloprid(25.2%)after three rinses.It was confirmed that the release process of imidacloprid was well regulated through changing external conditions such as light and temperature.