Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , 29 Zhongguancun East Road, Haidian District, Beijing 100190, China.
University of Chinese Academy of Sciences , 19A Yuquan Road, Beijing 100049, China.
ACS Appl Mater Interfaces. 2017 Feb 15;9(6):5382-5391. doi: 10.1021/acsami.6b14473. Epub 2017 Feb 3.
Surface modification of graphene is extremely important for applications. Here, we report a grafting-through method for grafting water-soluble polythiophenes onto reduced graphene oxide (RGO) sheets. As a result of tailoring of the side chains of the polythiophenes, the modified RGO sheets, that is, RGO-g-P3TOPA and RGO-g-P3TOPS, are positively and negatively charged, respectively. The grafted water-soluble polythiophenes provide the modified RGO sheets with good dispersibility in water and high photothermal conversion efficiencies (ca. 88%). Notably, the positively charged RGO-g-P3TOPA exhibits unprecedentedly excellent photothermal bactericidal activity, because the electrostatic attractions between RGO-g-P3TOPA and Escherichia coli (E. coli) bind them together, facilitating direct heat conduction through their interfaces: the minimum concentration of RGO-g-P3TOPA that kills 100% of E. coli is 2.5 μg mL, which is only 1/16th of that required for RGO-g-P3TOPS to exhibit a similar bactericidal activity. The direct heat conduction mechanism is supported by zeta-potential measurements and photothermal heating tests, in which the achieved temperature of the RGO-g-P3TOPA suspension (2.5 μg mL, 32 °C) that kills 100% of E. coli is found to be much lower than the thermoablation threshold of bacteria. Therefore, this research demonstrates a novel and superior method that combines photothermal heating effect and electrostatic attractions to efficiently kill bacteria.
石墨烯的表面修饰对于其应用至关重要。在这里，我们报告了一种将水溶性聚噻吩接枝到还原氧化石墨烯（RGO）片上的接枝贯穿方法。由于聚噻吩侧链的剪裁，改性的 RGO 片，即 RGO-g-P3TOPA 和 RGO-g-P3TOPS，分别带正电荷和负电荷。接枝的水溶性聚噻吩赋予改性 RGO 片在水中良好的分散性和高光热转换效率（约 88%）。值得注意的是，带正电荷的 RGO-g-P3TOPA 表现出前所未有的优异的光热杀菌活性，因为 RGO-g-P3TOPA 和大肠杆菌（E. coli）之间的静电吸引将它们结合在一起，通过它们的界面促进直接热传导：杀死 100%大肠杆菌所需的 RGO-g-P3TOPA 的最低浓度为 2.5 μg mL，仅为 RGO-g-P3TOPS 表现出类似杀菌活性所需浓度的 1/16。通过 zeta 电位测量和光热加热测试支持直接热传导机制，在该测试中，发现杀死 100%大肠杆菌的 RGO-g-P3TOPA 悬浮液（2.5 μg mL，32°C）的达到温度远低于细菌的热消融阈值。因此，这项研究展示了一种新颖而优越的方法，将光热加热效应和静电吸引结合起来，有效地杀死细菌。
