New trends in bioactive scaffolds: The importance of nanostructure

There are many criteria for an ideal scaffold that will stimulate the body's repair mechanisms to regenerate diseased or damaged bone to its original healthy state. These include having a pore network large and open enough for cells and blood vessels to penetrate and the ability to bond to bone. Sol-gel derived bioactive glasses have a nanoporosity that can control degradation rate. They can be foamed to produce scaffolds that mimic cancellous bone macrostructure. Bioactive glass foams with optimised nanoporosity are strong in compression; however, they have low toughness and pore strength when loaded in tension. Therefore an ideal scaffold would have all the properties of the glasses with enhanced toughness. This can only be achieved by creating new nanoscale composites. Resorbable polymers must interact with the silica based inorganic network at the nanoscale to maintain bioactivity and controlled resorption. This is a complex problem but may be the future of scaffold development. (C) 2008 Elsevier Ltd. All rights reserved.