Graphene oxide and green-synthesized reduced graphene oxide in chitosanbased nanocomposites

The first part of the paper concerns synthesis and characterization of two types of nanomaterials: graphene oxide (GO) prepared by modified Marcano method and reduced graphene oxide (rGO) synthesized using green reductant, L-ascorbic acid. Their structural properties were investigated by attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) and X-ray diffraction (XRD). Results confirmed that L-ascorbic acid is an effective reducing agent. Intensity of the oxygen-groups decreased dramatically what resulted in reduction of the GO interlayer spacing from 0.8 nm to 0.4 nm. The second part of the research was concentrated on the properties of chitosan nanocomposites modified with GO and rGO. Films were prepared by mixing of the chitosan solution with the nanoparticles dispersion. Scanning electron microscopy (SEM) was used to investigate the microstructure of the composites surface. In addition, wettability and pore size of the freeze-dried scaffolds were evaluated. Results of the mechanical tests (increase in Young’s modulus) and structural characterization confirmed that chitosan solution and GO dispersion can be mixed homogeneously. Reduction of GO during composite synthesis resulted in better dispersion of the nanosheets what increased surface roughness, wettability and stability in distilled water, PBS and Ringer’s solution compared to composite with GO. After detailed biological examination, rGO-modified nanocomposites can be potentially applied in tissue engineering