[32]. The prepared graphite oxide R406 concentration powder was dispersed in DI water to obtain an aqueous graphite oxide suspension with a yellow-brownish color. The suspension was centrifuged at 3,000 rpm/min for 10 min to eliminate unexfoliated graphitic plates and then at 10,000 rpm/min for 10 min to remove tiny graphite particles. Finally, a GO suspension was achieved by exfoliation of the filtered graphite oxide suspension through its sonication. Reduction of P5091 chemical structure graphene oxide was followed as described earlier [38] with slight modification. Synthesis of reduced graphene oxide Reduced graphene oxide was obtained from the reaction of a plant extract with graphene

oxide. In the typical reduction experiment, 10 mL of spinach leaf extract was added to 40 mL of 0.5 mg/mL aqueous GO solution and then the mixture was kept in a tightly sealed glass bottle and stirred at 30°C for 24 h. Then, using a magneto-stirrer heater, reduced graphene oxide suspension was stirred at 400 rpm SCH727965 cell line at a temperature of 30°C for 30 min. A homogeneous S-rGO suspension was

obtained without aggregation. Then, the functionalized S-rGO was filtered and washed with DI water. Finally, a black S-rGO dispersion was obtained. Characterization Ultraviolet–visible (UV–vis) spectra were obtained using a WPA (Biowave II, Biochrom Cambridge, UK). The aqueous suspension of GO and S-rGO was used as UV–vis samples, and deionized water was used as the reference. The particle size of dispersions was measured by Zetasizer Nano ZS90 (Malvern Instruments Limited, Malvern, UK). X-ray diffraction (XRD) analyses were carried out on an X-ray diffractometer (Bruker D8 DISCOVER, Bruker AXS GmBH, Karlsruhe, Germany). The high-resolution XRD patterns were measured at

3 kW with Cu target using a scintillation counter, and λ = 1.5406 A at 40 kV and 40 mA was recorded in the range of 2θ = 5° − 80°. The changes in the surface chemical bonding and surface composition were characterized using a Fourier transform infrared spectroscopy (FTIR) instrument (PerkinElmer Spectroscopy GX, Branford, CT, USA). A JSM-6700F semi-in-lens FE-SEM operating at 10 kV was used to acquire SEM images. The solid samples were transferred to a carbon tape held by an SEM sample holder for analyses. The analyses of the samples were carried out at an average working distance of 6 mm. Raman spectra of graphene oxide and reduced graphene oxide were measured by WITec these Alpha300 (Ulm, Germany) with a 532-nm laser. The calibration was initially made using an internal silicon reference at 500 cm−1 and gave a peak position resolution of less than 1 cm−1. The spectra were measured from 500 to 4,500 cm−1. All samples were deposited on glass slides in powder form without using any solvent. Surface images were measured using tapping-mode atomic force microscopy (SPA 400, SEIKO Instruments, Chiba, Japan) operating at room temperature. Height and phase images were recorded simultaneously using nanoprobe cantilevers (SI-DF20, SEIKO Instruments).