Improved biocompatibility and osteogenesis of porous graphene oxide/silk fibroin scaffold for potential applications in bone tissue engineering

Abstract

To better mimic the inherent porous architecture of the natural bone, we fabricated graphene oxide/silk fibroin (GO/SF) scaffolds using a salting leaching method, followed by in situ reduction and reinforcement with ascorbic acid. SEM images revealed that the scaffolds exhibited an interconnectivity porous structure both on the surface and throughout the interior. We found that the pore size could be readily adjusted by varying the concentration of GO in the scaffolds. FTIR results demonstrated that the addition of GO didn’t form chemical interaction between GO and SF, but it significantly increased the content of β-sheet structure from 46.36 % to 51.12 % and improved the thermal stability of the scaffolds. Moreover, the reduced graphene oxide/silk fibroin (rGO/SF) scaffolds exhibited a superior capacity to promote the adhesion, proliferation, and mineral deposition of mouse mesenchymal stem cell (MSCs) when compared to pure SF scaffolds. Notably, the equilibrium Young's modulus of the scaffolds gradually increased from 5.5±0.5 KPa to 14.6±2.1 KPa with the increment of rGO content. Osteogenic differentiation with higher BSP (2. 84-fold) and RUNX2 (2.91-fold) expression level was also observed in 3 % rGO scaffold, suggesting a strong inclination towards bone formation. Based on these findings, the prepared rGO/SF scaffold in this study hold great potential as a viable option for bone tissue engineering.