Abstract

300 000 bone graft operations take place in Europe each year. Surgeons currently prefer to take bone from the pelvis and move it to a defect site but it is painful, can lead to complications and the recovery rate is slow. A synthetic graft material is required that can help the body regenerate bone defects. There are many design criteria for a scaffold or effective regeneration of bone defects. A scaffold must stimulate bone growth, dissolving as the bone regenerates. To be an effective template the scaffold must have an interconnected pore network and for new bone to survive, blood vessels must penetrate. Scaffolds with this potential have been developed by foaming bioactive glasses. Bioactive glasses are thought to stimulate new bone growth by activating specific genes in bone cells. There is potential for the scaffolds to be used in tissue engineering applications, where cells are first cultured on the scaffold prior to implantation. The latest generation of bioactive glass scaffolds will be shown and products will be available in the near future. In vitro and in vivo results will be discussed. The stem cell response to scaffolds and nanoparticles will be described. The limitation of bioactive glasses is that they are brittle. Composites have been developed but the inorganic and organic phases tend to resorb at different rates, leading to material instability. Hybrids have the potential to have bespoke design of mechanical properties and congruent degradation through interpenetrating networks of inorganic and organic components, e.g. sol-gel silica and biodegradable polymers. Covalent coupling between the components is critical to their success. How hybrids can support blood vessel growth will also be demonstrated.