Multilayered Graphene Hydrogel Membranes for Guided Bone Regeneration

Multilayered graphene (MGH) membranes were used as a representative graphene material to explore their use for guided bone regeneration (GBR). In a typical rat calvarial defect model, a critical diameter of 5 mm circular defect was created. A fracture of the defect of this size cannot be healed during the lifetime of the animal because rat calvaria lack blood supply and muscle tissue. Calvarial defects in the untreated control group were bridged primarily by fibrous connective tissue and the bone formation was restricted to the edges of the host bone. Subtotal repair with immature bone is present in the titanium membrane group, and the remainder of the defect was spanned by fibrous connective tissue. In the collapsed MGH membrane group, the defects were closed almost entirely by immature lamellar bone. The new bone grown from the lateral margins contained a greater number of small vascular channels, which appeared to facilitate differentiation of the new bone from the host bone. No tissue resembling cartilage morphologically was observed in any group. The speed of bone regeneration using the fluorescent labeling technique was also investigated. The yellow tetracycline labels were seen more pronounced in the MGH group than the others, which was a reflection of new bone formation after 2 weeks of operation.