Wang Yuhao, Sukhishvili Svetlana A
Department of Biomedical Engineering, Chemistry and Biological Sciences, Stevens Institute of Technology, 507 River Street, Hoboken, NJ, 07030, USA.
Department of Materials Science and Engineering, Texas A&M University, 575 Ross St., College Station, TX, 77843, USA.
Macromol Rapid Commun. 2017 Aug;38(16). doi: 10.1002/marc.201700242. Epub 2017 Jun 12.
Spontaneous formation of polymer nanoparticles of well-defined, <100 nm sizes with controlled solid/hollow morphology and fluorescent properties is reported. The nanoparticle formation is assisted by temperature-triggered nucleation of an amphiphilic polymer-poly(N-isopropylacrylamide) (PNIPAM)-and mediated by hydrogen bonding of the emerged nuclei with tannic acid (TA). The pH of solution and TA/PNIPAM ratios are explored as parameters that define TA/PNIPAM assembly. Well-defined nanoparticles are formed in a wide range of neutral pH when the TA/PNIPAM ratio exceeds its critical, pH-dependent value. Dynamic light scattering and zeta potential measurements as well as atomic force microscopy and electron energy loss spectroscopy indicate that solid nanoparticles or nanocapsules are formed depending on the solution pH and that enhanced ionization of TA favors hollow morphology. Nanocapsules exhibit label-free fluorescence at neutral pH values and therefore can be useful in imaging applications.
据报道，可自发形成尺寸明确、小于100纳米、具有可控的实心/空心形态及荧光特性的聚合物纳米颗粒。纳米颗粒的形成由两亲性聚合物聚（N-异丙基丙烯酰胺）（PNIPAM）的温度触发成核辅助，并由新出现的核与单宁酸（TA）的氢键介导。研究了溶液的pH值和TA/PNIPAM比例作为定义TA/PNIPAM组装的参数。当TA/PNIPAM比例超过其临界的、依赖pH值的值时，在很宽的中性pH范围内会形成明确的纳米颗粒。动态光散射和zeta电位测量以及原子力显微镜和电子能量损失谱表明，根据溶液pH值会形成实心纳米颗粒或纳米胶囊，并且TA的增强电离有利于空心形态。纳米胶囊在中性pH值下表现出无标记荧光，因此可用于成像应用。
