Green fabrication of porous silk fibroin/graphene oxide hybrid scaffolds for bone tissue engineering

Abstract

The fabrication of novel scaffolds providing mechanical support and promoting tissue regeneration is urgently needed in bone tissue engineering. In the present study, three-dimensional (3-D) porous scaffolds based on silk fibroin (SF) and graphene oxide (GO) were prepared by freeze-drying. It is also worth noting that glycerol was blended with the SF solution and induced silk crystallization during the lyophilization process, and such non-use of organic solvents realized the concept of “green” preparation. With the incorporation of GO, the average pore diameter of the scaffolds decreased and their porosity changes were slight. The glycerol-treated scaffolds showed a stable silk II structure and their compressive modulus were improved significantly after GO was added. The biological performance of the SF/GO scaffolds including biodegradation behavior, drug release properties and biocompatibility were also investigated. Compared with the SF scaffold, the incorporation of GO enhanced the ability of the scaffolds to resist enzyme degradation. Simvastatin (SIM) was chosen as a model drug for release studies from the scaffolds. The results indicated that SIM release was dependant on the GO content within the scaffolds. MC3T3-E1 cells cultured in the hybrid scaffolds with moderate GO content demonstrated obviously enhanced osteogenic proliferation compared to that in the SF scaffolds without or with high concentration GO. Furthermore, the incorporation of SIM was beneficial to the growth of osteoblasts and the SF/GO/SIM scaffolds showed better cytocompatibility. These new 3-D SF/GO hybrid scaffolds with sustained drug release capacity would offer promising potential as platforms for bone tissue regeneration.