A graded graphene oxide-hydroxyapatite/silk fibroin biomimetic scaffold for bone tissue engineering

- The cGO-HA/SF scaffolds have a gradient structure similar with natural bone.
- The carboxylation of GO can promote the growth of HA nanoparticles on the surface of cGO.
- Mechanical properties of the composite scaffolds had been significantly improved after embedding with GO.
- cGO-HA/SF scaffolds show excellent cytocompatibility and accelerate osteoblast differentiation.

To better mimic natural bone, a graphene oxide-hydroxyapatite/silk fibroin (cGO-HA/SF) scaffold was fabricated by biomineralizing carboxylated GO sheets, blending with SF, and freeze-drying. The material has increasing porosity and decreasing density from outside to inside. Analysis of GO mineralization in simulated body fluid indicated that carboxylation and Chitosan may synergistically regulate HA growth along the c-axis of weakly crystalline, rod-like GO-HA particles. Compared with HA/SF gradient composites, a cGO-HA gradient scaffold with cGO:HA mass ratio 1:4 has 5-fold and 2.5-fold higher compressive strength and compressive modulus, respectively. Additionally, the cGO-HA/SF composite stimulated mouse mesenchymal stem cell adhesion and proliferation, alkaline phosphatase secretion, and mineral deposition more strongly than HA/SF and pure HA scaffolds. Hence, the material may prove to be an excellent and versatile scaffold for bone tissue engineering.

Mineralization of the carboxylated GO.212