School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT) University, Bhubaneswar, Odisha, 751024, India.
Tata Steel Limited, Jajpur, Odisha, 755026, India.
Adv Mater. 2018 Feb;30(7). doi: 10.1002/adma.201702149. Epub 2018 Jan 8.
Nanomaterials such as silver nanoparticles and graphene-based composites are known to exhibit biocidal activities. However, interactions with surrounding medium or supporting substrates can significantly influence this activity. Here, it is shown that superior antimicrobial properties of natural shellac-derived graphene oxide (GO) coatings is obtained on metallic films, such as Zn, Ni, Sn, and steel. It is also found that such activities are directly correlated to the electrical conductivity of the GO-metal systems; the higher the conductivity the better is the antibacterial activity. GO-metal substrate interactions serve as an efficient electron sink for the bacterial respiratory pathway, where electrons modify oxygen containing functional groups on GO surfaces to generate reactive oxygen species (ROS). A concerted effect of nonoxidative electron transfer mechanism and consequent ROS mediated oxidative stress to the bacteria result in an enhanced antimicrobial action of naturally derived GO-metal films. The lack of germicidal effect in exposed cells for GO supported on electrically nonconductive substrates such as glass corroborates the above hypothesis. The results can lead to new GO coated antibacterial metal surfaces important for environmental and biomedical applications.
纳米材料，如银纳米粒子和基于石墨烯的复合材料，已知具有杀菌活性。然而，与周围介质或支撑基底的相互作用会显著影响这种活性。在这里，研究表明，在金属薄膜（如 Zn、Ni、Sn 和钢）上获得了天然紫胶衍生氧化石墨烯（GO）涂层的卓越抗菌性能。还发现，这种活性与 GO-金属系统的电导率直接相关；电导率越高，抗菌活性越好。GO-金属基底相互作用作为细菌呼吸途径的有效电子汇，其中电子修饰 GO 表面上含氧官能团以生成活性氧物种（ROS）。非氧化电子转移机制的协同效应以及随后的 ROS 介导的对细菌的氧化应激导致天然衍生的 GO-金属薄膜的抗菌作用增强。在玻璃等不导电基底上支撑的 GO 暴露细胞中缺乏杀菌效果证实了上述假设。该结果可为环境和生物医学应用中重要的具有抗菌性的 GO 涂层金属表面提供新的思路。
