Tang Yiyuan, Chen Kai, Li Jiacheng, Feng Yuhong, Yu Gaobo, Wang Longzheng, Zhao Xinyu, Peng Yang, Zhang Quan
Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, College of Materials and Chemical Engineering, Hainan University 58 Renmin Road Haikou 570228 Hainan Province China
RSC Adv. 2018 Sep 18;8(56):32193-32199. doi: 10.1039/c8ra05503c. eCollection 2018 Sep 12.
In this study, a pH-responsive amphiphilic alginate (Ugi-Alg) was synthesized Ugi reaction without using a catalyst. The structure of Ugi-Alg was confirmed by FT-IR and H NMR spectroscopy. Amphiphilic alginate can form micelles in an aqueous medium due to it's amphiphilic nature.. The impacts of Na concentration and pH on the micelle size were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The dynamic light scattering observations showed that micelle size increases with the decrease in Na concentration in aqueous solution. However, the micelle size decreases first and then increases as the pH value decreases from 5.3 to 2.0. Transmission electron microscopy confirmed that the mean size of micelles is 30-200 nm. In addition, a model hydrophobic pesticide (acetamiprid) was loaded in the micelles. The encapsulation efficiency and release behavior of micelles were studied, which could be controlled by Na concentration and pH. The results indicated that encapsulation efficiency of acetamiprid increases from 55% to 96% due to the increase in Na concentration from 0.01 M to 0.3 M. Moreover, with the decrease in pH from 5.3 to 2.0, encapsulation efficiency increases from 55% to 80%. Furthermore, the data of acetamiprid release kinetics could be well-fitted by the Weibull model.
在本研究中，在不使用催化剂的情况下通过乌吉反应合成了一种pH响应性两亲性藻酸盐（Ugi-Alg）。通过傅里叶变换红外光谱（FT-IR）和核磁共振氢谱（H NMR）对Ugi-Alg的结构进行了确认。两亲性藻酸盐由于其两亲性本质可在水性介质中形成胶束。通过动态光散射（DLS）和透射电子显微镜（TEM）表征了Na浓度和pH对胶束尺寸的影响。动态光散射观察结果表明，胶束尺寸随水溶液中Na浓度的降低而增大。然而，随着pH值从5.3降至2.0，胶束尺寸先减小后增大。透射电子显微镜证实胶束的平均尺寸为30 - 200 nm。此外，将一种典型的疏水性农药（啶虫脒）负载到胶束中。研究了胶束的包封效率和释放行为，其可由Na浓度和pH控制。结果表明，由于Na浓度从0.01 M增加到0.3 M，啶虫脒的包封效率从55%提高到96%。此外，随着pH从5.3降至2.0，包封效率从55%提高到80%。此外，啶虫脒释放动力学数据可以很好地用韦布尔模型拟合。
