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Green tea polyphenol-reduced graphene oxide: derivatisation, reduction efficiency, reduction mechanism and cytotoxicity

Abdullah, M. F.; Zakaria, R.; Zein, S. H. S.

Authors

M. F. Abdullah

R. Zakaria

Dr Sharif Zein S.H.Zein@hull.ac.uk
Reader in Biorefinery Processes and Reaction Engineering

Abstract

This paper reports on the derivatisation, reduction efficiency, reduction mechanism and cytotoxicity of green tea polyphenol-reduced graphene oxide (GTP-RGO). The reduction of graphene oxide (GO) at 90°C using a weight ratio (WR) of GTP/GO=1 resulted in the production of a stable GTP-RGO dispersion in aqueous media, as indicated by the results of ultravioletvisible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and the measurement of zeta potential and electrophoretic mobility. In addition, the results from UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis indicated the comparable reduction ability of GTP relative to the standard reducing agent, hydrazine (N2H4). The removal mechanism of epoxy group from GO via reduction reaction with GTP was investigated by implementing hybrid functional method of Becke-3-parameters-Lee-Yang-Parr (B3LYP)using Gaussian 09 software. The energy and frequency calculations showed that the GO reduction using GTP was more spontaneous and relatively took place faster than the reduction using N2H4, as evidenced by higher entropy change (ΔS) (0.039 kcal/mol·K) and lower Gibbs free energy (ΔG) barrier (58.880 kcal/mol).The cytotoxicities of GO and GTP-RGO samples were evaluated against human colonic fibroblasts cells (CCD-18Co). The GO sample was determined to be toxic even at low concentration (6.25 μg/mL), while the GTP-RGO sample possesses notably low toxicity at the same concentration. The cell culture experiments revealed that the incorporation of GTP led to a decrease in the toxicity of GTP-RGO samples.

Publication Date Jul 30, 2014
Journal RSC advances
Print ISSN 2046-2069
Electronic ISSN 2046-2069
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 4
Issue 65
Pages 34510-34518
Institution Citation Abdullah, M. F., Zakaria, R., & Zein, S. H. S. (2014). Green tea polyphenol-reduced graphene oxide: derivatisation, reduction efficiency, reduction mechanism and cytotoxicity. RSC advances, 4(65), 34510-34518. https://doi.org/10.1039/c4ra04292a
DOI https://doi.org/10.1039/c4ra04292a
Keywords Graphene oxide; Reduced graphene oxide; Green tea polyphenol; Reduction mechanism; Cytoxicity
Publisher URL http://pubs.rsc.org/en/content/articlelanding/2014/ra/c4ra04292a#!divAbstract
Copyright Statement ©2016 University of Hull
Additional Information This is the authors accepted manuscript of an article published in RSC advances, 2014, v.4.

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