Details

Autor(en) / Beteiligte

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

Titel

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

Ist Teil von

• RSC advances, 2014-01, Vol.4 (65), p.34510-34518

Erscheinungsjahr

2014

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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 ultraviolet-visible (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 (N 2 H 4 ). The removal mechanism of epoxy groups from GO via reduction reaction with GTP was investigated by implementing the 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 took place relatively faster than the reduction using N 2 H 4 , as evidenced by a higher entropy change (Δ S ) (0.039 kcal mol −1 K −1 ) and lower Gibbs free energy (Δ G ) barrier (58.880 kcal mol −1 ). The cytotoxicities of the GO and GTP–RGO samples were evaluated against human colonic fibroblast cells (CCD-18Co). The GO sample was determined to be toxic even at low concentration (6.25 μg mL −1 ), 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.