Ordered Mesoporous Microspheres for Bone Grafting and Drug Delivery

Bioactive microspheres with ordered mesoporous structure have been synthesized by means of the evaporation-induced self-assembly (EISA) method and following an aerosol-assisted route. The bioactive microspheres belong to the SiO2-CaO-P2O5 Systems, and the mesoporous structure closely depends on the structure-directing agent as well as its interaction with the Ca2+ cations during the mesophase formation. Among the different tested surfactants, the triblock copolymer F127 leads to hexagonal ordered structures for low CaO contents, P123 leads to wormlike mesoporous structures for any CaO content, whereas the ionic surfactant cetyltrimethyl ammonium bromide (C16TAB) does not produce accessible mesopores at the external surface, for any CaO content. All the mesoporous SiO2-CaO-P2O5 microspheres develop an apatite like layer when reacting with simulated body fluid. Preliminary tests indicate the capability to load and release triclosan with kinetic profiles that depend on the pore structure, thus showing interesting features to be used in periodontal regenerative surgery and infection profilaxis.