Single-Walled Carbon Nanotube Membranes Accelerate Active Osteogenesis in Bone Defects: Potential of Guided Bone Regeneration Membranes br

Carbon nanotubes (CNTs) are potentially important biomaterials because of their chemical, physical, and biologicalproperties. Our research indicates that CNTs exhibit highcompatibility with bone tissue. The guided bone regeneration(GBR) technique is commonly applied to reconstruct alveolarbone and treat peri-implant bone defects. In GBR, bone defects arecovered with a barrier membrane to prevent the entry ofnonosteogenic cells such as epithelial cells andfibroblasts. Thebarrier membrane also maintains a space for new bone formation.However, the mechanical and biological properties of materialspreviously used in clinical practice sometimes delayed boneregeneration. In this study, we developed a CNT-based membranefor GBR exhibiting high strength to provide a space for bone formation and provide cellular shielding to induce osteogenesis. TheCNT membrane was made via the dispersion of single-walled CNTs (SWCNTs) in hyaluronic acid solution followed byfiltration.The CNT membrane assumed a nanostructure surface due to the bundled SWCNTs and exhibited high strength and hydrophilicityafter oxidation. In addition, the membrane promoted the proliferation of osteoblasts but not nonosteogenic cells. CNT membraneswere used to cover experimental bone defects made in rat calvaria. At 8 weeks after surgery, more extensive bone formation wasobserved in membrane-covered defects compared with bone defects not covered with membrane. Almost no diffusion of CNTs was observed around the membrane. These results indicate that the CNT membrane has adequate strength, stability, and surface characteristics for osteoblasts, and its shielding properties promote bone formation. Demonstration of the safety and osteogenicpotential of the CNT membranes through further animal studies should facilitate their clinical application in GBR