A comparative study of the bioactivities of collagen scaffold coated with graphene oxide and reduced graphene oxide.

Abstract

Graphene oxide (GO) is a single layer carbon sheet with a thickness of less than 1 nm. GO has good dispersibility due to surface modifications with many functional groups. Reduced graphene oxide(RGO) is produced by the reduction of GO. We examined the bioactivity of GO and RGO films, and collagen scaffold coated with GO and RGO. GO films were fabricated on a culture dish. Some GO films were chemically reduced with ascorbic acid or sodium hydrosulfite solution. The biological properties of each film were evaluated by SEM, DNA content and alkaline phosphatase (ALP) activity following seeding with MC3T3-E1 cells. The adsorption of calcium on each film was also assessed. Subsequently,GO-and RGO-coated collagen scaffolds were prepared and characterized by SEM observation and compression tests. Each scaffold was implanted into the subcutaneous tissue of the back of rats. Measurements of DNA content and cell ingrowth area of the implanted scaffolds were performed 10 days post-surgery. The results show that GO and RGO possess different biological properties. ALP activity and calcium adsorption were strongly enhanced by RGO, suggesting that RGO is effective for osteogenic differentiation. SEM showed that RGO-modified collagen scaffolds have rough irregular surfaces. The compressive strength of the RGO-coated scaffolds were greater than that of the GO-coated and non-coated scaffolds. Ingrowth of cells was frequently observed in the RGO-coated scaffolds. Taken together, these results suggest that GO and RGO possess different biological properties, and that RGO is more effective for biomedical applications than GO.