A study on in vitro and in vivo bioactivity of silk fibroin / nano-hydroxyapatite / graphene oxide composite scaffolds with directional channels

As an important carrier of cells and growth factors, scaffold materials have attracted attention in bone tissue engineering, but how to construct materials with both component and structural advantages is still a challenge. In this study, silk fibroin (SF) / nano-hydroxyapatite (nHAp) / graphene oxide (GO) composite scaffolds with directional channels were prepared by directional temperature field freeze-drying technique. The characterization, morphology, degradation rate, biocompatibility and bioactivity of directed channel SF/nHAp/GO scaffolds were studied systematically. As a comparison, the series of studies were also conducted in SF scaffolds, SF/nHAp scaffolds and undirected SF/nHAp/GO scaffolds. The characterization results showed that the directed channel SF/nHAp/GO scaffolds had better connectivity, more suitable porosity, degradation rate for osteogenesis and ability to induce bone-like apatite. The cell compatibility results showed that the directed channel SF/nHAp/GO scaffolds were more beneficial to the adhesion and proliferation of bone marrow mesenchymal stem cells (BMSCs). And the expression of osteogenic genes was all up-regulated by RT-PCR. The in vivo experimental results showed that the directed channel SF/nHAp/GO scaffolds showed stronger biological activity and osseointegration ability. The composite scaffolds were non-toxic in vitro and in vivo. Therefore, this material may have great application potential in repairing bone tissue defects. It provides a meaningful reference for the further study of scaffold materials with directional channels such as dental and orthopedical repair materials from the material composition and structure design.