Unveiling the Synergistic Role of Oxygen Functional Groups in the Graphene-Mediated Oxidation of Glutathione
Unveiling the Synergistic Role of Oxygen Functional Groups in the Graphene-Mediated Oxidation of Glutathione
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DOI：
10.1021/acsami.0c11539
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发表时间：
2020-10-14
影响因子：
9.5
通讯作者：
Gilbertson, Leanne M.
中科院分区：
文献类型：
--
作者：
Wang, Yan;Basdogan, Yasemin;Gilbertson, Leanne M.
这是首次报道了在室温下，氧化石墨烯(GO)上的环氧化物直接氧化谷胱甘肽(GSH)中的硫醇基的原子尺度机理。通过实验和计算相结合的方法确定了所提出的反应机理；通过检测GSH暴露前后GO表面化学变化来确定反应的活性中心，密度泛函理论(DFT)计算确定了可能的GO-GSH反应方案的反应势垒。这些发现建立在先前建立的石墨纳米碳表面氧化GSH的催化机理的基础上，并重要地确定了在低氧环境中变得重要的直接反应机理。实验结果表明，环氧化物是与GSH反应的活性中心，我们用反应势垒的密度泛函计算证实了这一点，并进一步确认了GO表面相邻环氧化物和羟基之间的协同作用。在特定氧位置的直接氧化机制为通过表面化学反应控制GO的化学反应提供了洞察力。这一见解对于加深我们对GO细胞毒性中氧化应激途径的理解以及为GO应用提供合理的材料设计以利用这种反应是至关重要的。
This is the first report of an atomic-scale direct oxidation mechanism of the thiol group in glutathione (GSH) by epoxides on graphene oxide (GO) at room temperature. The proposed reaction mechanism is determined using a coupled experimental and computational approach; active sites for the reaction are determined through examination of GO surface chemistry changes before and after exposure to GSH, and density functional theory (DFT) calculations determine the reaction barriers for the possible GO-GSH reaction schemes. The findings build on the previously established catalytic mechanism of GSH oxidation by graphenic nanocarbon surfaces and importantly identify the direct reaction mechanism which becomes important in low-oxygen environments. Experimental results suggest epoxides as the active sites for the reaction with GSH, which we confirm using DFT calculations of reaction barriers and further identify a synergism between the adjacent epoxide and hydroxyl groups on the GO surface. The direct oxidation mechanism at specific oxygen sites offers insight into controlling GO chemical reactivity through surface chemistry manipulations. This insight is critical for furthering our understanding of GO oxidative stress pathways in cytotoxicity as well as for providing rational material design for GO applications that can leverage this reaction.