Alkaline phosphatase activity PMEF cells were cultured in a 48-well culture dish at a density of 5 × 103 cells per well for 4 days. Then medium was replaced with treatment solution, which was DMEM containing 5% serum plus GO or S-rGO. After 4 days, the alkaline-phosphatase activity was measured according to the method described by manufacturer’s instructions (DALP-250, QuantiChrom™ Alkaline Phosphatase Assay Kit, Gentaur, Belgium). selleck products The plates were incubated at 37°C for 30 min. The amount
of released p-nitrophenol was measured at 405 nm in a 96-well microplate reader. Enzyme activity was evaluated as the amount of nitrophenol released through the enzymatic reaction, and absorbance was recorded using a microplate Selleck Entospletinib reader (Bio-RAD 680, Hercules, CA, USA) at 405 nm. For normalization, the
total protein content was measured using a bicinchoninic acid protein assay kit. Thus, the alkaline phosphatase (ALP) activity was expressed and normalized by the total protein content (U/mg). Results and discussion Reduction of GO by SLE Reduction of GO was carried out at room temperature using spinach leaf extract. On completion of the reduction process, the color change from brown to black provides the soluble reduced product (inset of the Figure 1). This preliminary experiment suggested that spinach leaf extracts have the ability to remove oxygen-containing moieties present in GO, which is the piece of evidence for reduction process. Further, the spectra of GO and S-rGO were recorded using UV–vis absorption spectroscopy, check details which is a simple and valuable technique. GO shows a maximum absorption peak at 231 nm which was attributed to the π-π* transitions of the aromatic C-C bonds and a weak Osimertinib concentration shoulder at 300 nm due to n-π* transitions of C=O bonds. After complete reduction, a red shift of this characteristic peak was observed at 265 nm for S-rGO (Figure 1); this indicates that electronic conjugation was restored. When SLE was used as control, it showed two peaks at 450 and 650 nm, which are different from those of GO and S-rGO. As GO had
a light brownish color and S-rGO a black color suspension, as we have expected, the optical absorption of all S-rGO was higher than that of GO. In agreement with our results, Thakur and Karak observed a characteristics peak value at 268 nm using phytoextracts for both Camellia sinensis peel aqueous extract-reduced GO and Mesua ferrea leaf aqueous extract-reduced GO . Figure 1 UV–vis absorption spectra of SLE, GO, and S-rGO suspensions in water. XRD analysis XRD is an effective technique to investigate the interlayer changes and the crystalline nature of the synthesized material. XRD patterns of GO and S-rGO are shown in Figure 2. Pristine graphite exhibits a basal reflection (002) peak at 2θ = 26.6° corresponding to a d spacing of 0.335 nm.