Wang Meizhen, Li Zhangqiang, Zhang Yunyun, Li Yue, Li Na, Huang Dan, Xu Baile
School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China; Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Hangzhou 310012, China.
School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China.
J Hazard Mater. 2021 Jun 15;412:125333. doi: 10.1016/j.jhazmat.2021.125333. Epub 2021 Feb 5.
Graphene oxide (GO) has high-efficient antibacterial activity to diverse pathogenic bacteria. However, the detailed antibacterial mechanism of GO is not fully clear. Herein the antibacterial properties of GO against model Gram-positive (Gram+) (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative (Gram-) bacteria (Pseudomonas aeruginosa and Escherichia coli) were compared by plate count method. Results showed that 4 mg/L of GO induced the mortality of Gram+ and Gram- bacteria by > 99% and < 25%, respectively. GO had greater adsorption affinity to teichoic acids, the unique components existing in the cell wall of Gram+ bacteria, mainly via π-π interaction. The adsorption efficiency of teichoic acids was 27 times higher than that of peptidoglycan when they were simultaneously exposed to 100 mg/L GO. The superior adsorption of teichoic acids onto GO increased one order of magnitude of atlA expression, the autolysin related gene. As a result, these accelerated bacterial death by hydrolyzing peptidoglycan in cell walls. Exogenous addition of 50 mg/L teichoic acids could impair 4-5 fold of antibacterial activity of GO against S. aureus. These new findings illuminate the antibacterial mechanism of GO against Gram+ bacteria, which paves the way for the further application of graphene-based materials in water disinfection and pathogen control.
氧化石墨烯（GO）对多种病原菌具有高效抗菌活性。然而，GO的详细抗菌机制尚未完全明确。在此，通过平板计数法比较了GO对革兰氏阳性（Gram+）（金黄色葡萄球菌和表皮葡萄球菌）和革兰氏阴性（Gram-）细菌（铜绿假单胞菌和大肠杆菌）的抗菌性能。结果表明，4mg/L的GO分别使革兰氏阳性菌和革兰氏阴性菌的死亡率>99%和<25%。GO对磷壁酸具有更强的吸附亲和力，磷壁酸是革兰氏阳性菌细胞壁中存在的独特成分，主要通过π-π相互作用。当磷壁酸和肽聚糖同时暴露于100mg/L的GO时，磷壁酸的吸附效率比肽聚糖高27倍。磷壁酸在GO上的优越吸附使自溶素相关基因atlA的表达增加了一个数量级。结果，这些通过水解细胞壁中的肽聚糖加速了细菌死亡。外源添加50mg/L的磷壁酸会削弱GO对金黄色葡萄球菌4-5倍的抗菌活性。这些新发现阐明了GO对革兰氏阳性菌的抗菌机制，为基于石墨烯的材料在水消毒和病原体控制中的进一步应用铺平了道路。
