High-performance mesoporous bioceramics mimicking bone mineralization

The preparation of bioceramics with ordered mesoporous structures is of importance for biomedical technology, for the design of bone and dental grafts with regeneration purposes. Here we demonstrate that hexagonal mesoporous SiO2-CaO-P2O5 bioglasses (MBG) with high calcium content are the first known bioceramics that exhibit amorphous calcium phosphate (ACP)-octacalcium phosphate (OCP)-calcium deficient carbonatehydroxyapatite (CDHA) maturation as biomineralization governing mechanism in simulated body fluid (SBF), similarly to the in vivo biomineralization process. The unique characteristics of hexagonal MBGs lead to a local acid pH at the bioceramic surface that allows the formation of metastable OCP. Besides, 3D cubic MBG has been also synthesized, exhibiting higher surface area and porosity. The 3D reconstruction carried out by electron microscopy evidence a 3D bicontinuous network comprising a pair of rods mutually intertwined, creating the pore system available in three dimensions. This 3D pore system provides not only high surface area and porosity but also easier interchange of ions, increasing mass transport and diffusion processes. The final result is that 3D cubic MBGs exhibit an accelerated bioactivity behavior, forming a bonelike apatite phase on the surface, I h after coming into contact with SBF.