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Issue 3, 2019
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Optimizing oxygen functional groups in graphene quantum dots for improved antioxidant mechanism

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Abstract

The development of new antioxidants with quick absorbance of free radicals and excellent biocompatibility has drawn intensive attention in recent years. Graphene quantum dots (GQDs) seemed to be one of the most promising antioxidants because of their appropriate antioxidant activity, unique structure, excellent biocompatibility, and low toxicity. However, the relatively low antioxidant activity in comparison with inorganic semiconductor materials and unclear antioxidant mechanism limited their application in cells. In this paper, we further explored their antioxidant mechanism by focusing on the relationship between antioxidant activity and surface oxygen functional groups. The total oxygen fraction was controlled by post-preparation reduction using NaBH4 and the type of oxygen functional groups was adjusted by free radicals during the preparation of GQDs. The degree of reduction and content of surface oxygen groups were determined by X-ray photoelectron spectroscopy (XPS), and the antioxidant activity was obtained by scavenging of 1,1-diphenyl-2-picryl-hydrazyl (DPPH˙) and hydroxyl (˙OH) free radicals. Based on the analysis of XPS, Raman, and Fourier-transform infrared (FT-IR) spectra, the relationship between antioxidant activity and the surface oxygen groups of GQDs was obtained, and the antioxidant mechanism of GQDs was revealed with a particular specification of each oxygen group in the antioxidant activity of GQDs, meanwhile, the biocompatibility of GQDs has been demonstrated by cytotoxicity tests. We hope that our results will provide a new insight into a complete antioxidant mechanism of GQDs.

Graphical abstract: Optimizing oxygen functional groups in graphene quantum dots for improved antioxidant mechanism

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Publication details

The article was received on 31 Oct 2018, accepted on 05 Dec 2018 and first published on 07 Dec 2018


Article type: Paper
DOI: 10.1039/C8CP06768F
Citation: Phys. Chem. Chem. Phys., 2019,21, 1336-1343
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    Optimizing oxygen functional groups in graphene quantum dots for improved antioxidant mechanism

    Y. Wang, W. Kong, L. Wang, J. Z. Zhang, Y. Li, X. Liu and Y. Li, Phys. Chem. Chem. Phys., 2019, 21, 1336
    DOI: 10.1039/C8CP06768F

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