Glasses in bone regeneration: A multiscale issue

3D scaffolds based in mesoporous bioactive glasses (MBGs) are being widely investigated to use in bone tissue engineering (TE) applications. These scaffolds are often obtained by rapid prototyping (RP) and exhibit an array of interconnected pores in a hierarchy of sizes. The ordered mesopore network (around 4 nm in diameter) is optimal for the adsorption and release of bone inductor biomolecules, and the arrangement of macropores over 100 μm facilitates the bone cell ingrowths and angiogenesis. Nevertheless MBG composition can be varied almost infinitely at the atomic scale by including in the glass network oxides of inorganic elements with a therapeutic action. In this article the synthesis and characterization of MBG scaffolds based on the 80%SiO2-15%CaO-5%P2O5 (in mol-%) glass with substitutions up to 3.5% of Ga2O3 or Ce2O3 or 7.0% of ZnO are revisited. The substituent inclusion and the RP processing slightly decrease the surface area, the pore volume and the mesoporous order as well as their bioactive response in solutions mimicking blood plasma. However, these values still remain useful for bone TE applications. Results exhibiting the bactericide action of MBG scaffolds containing ZnO are also presented.