Quinone-mediated microbial synthesis of reduced graphene oxide with peroxidase-like activity

The effects of different quinones on graphene oxide (GO) reduction by Shewanella oneidensis MR-1 and the peroxidase activity of the resultant reduced graphene oxide (QRGO) were studied. The presence of 100 μM anthraquinone-2-sulfonate (AQS), anthraquinone-2,6-disulfonate and 5-hydroxy-1,4-naphthoquinone could lead to 1.6–2.8-fold increase in GO reduction rate, whereas anthraquinone-2-carboxylate slowed down the reduction. The stimulating effects of AQS increased with the increase of its concentration (10–100 μM). The mediated effects were proved by direct GO reduction by microbially reduced AQS. The mediated reduction of GO to QRGO was characterized by UV–vis, XRD, FTIR, Raman spectra, XPS, TEM and AFM, respectively. The as-prepared QRGO possessed peroxidase-like activity, which could catalyze the oxidation of 3,3′5,5′-tetramethylbenzidine by H2O2, and followed Michealis–Menten kinetics. A colorimetric sensor for quantitative determination of glucose based on the peroxidase activity of QRGO was developed over a range of 1–120 μM with a detection limit of 1 μM.