2.2. GOSA/RGOSA Scaffold Fabrication and Preparation
The graphene-based composite scaffolds were fabricated by a technique involving solution mixing, freeze-drying, crosslinking, and bio-reduction as described previously [24]. Briefly, 2 wt. % sodium alginate powder was dissolved in deionized water until a transparent solution is obtained. Then, GO (synthesized by modified hummers’ method as described earlier [34]) was added to the solution to get a final concentration of 0.5 and 1 wt. %. The mixture was frozen overnight at -18 °C and fabricated into a porous structure by the freeze-drying technique. The obtained aerogels were crosslinked in 1 M calcium chloride (CaCl2) solution for 1 hour and freeze-dried again to form GOSA scaffolds. The obtained scaffolds are named as GOSA0.5 and GOSA1 according to the concentration of GO in the composite sample. SA scaffolds were fabricated without the addition of GO. In order to make conductive RGOSA scaffolds, the obtained GOSA0.5 and GOSA1 scaffolds were treated with gelatin solution (1 mg mL-1) at 95°C to produce conductive RGOSA0.5 and RGOSA1 scaffolds, respectively. The prepared scaffolds were cut in 2 mm thickness (diameter ≈14 mm) until further use. Details on the physicochemical characterization of the GOSA and RGOSA scaffolds can be found in [24].