Synthesis and characterization of mesoporous CaO-MO-SiO₂-P ₂O₅ (M = Mg, Zn, Cu) bioactive glasses/composites

Mesoporous CaO-MO-SiO₂-P₂O₅ (M = Mg, Zn, Cu) bioactive glasses/composites have been prepared by a one-pot synthesis route of simultaneous evaporation-induced self-assembly of Ca, P, Si and M sources. The effects of the substitution of CaO by MO in the mesoporous bioactive glasses/composites on the mesoporous structure and hydroxyapatite (HA)-forming ability were studied. The amorphous silicate can be detected on all the mesoporous CaO-MO-SiO₂-P₂O₅ (M = Mg, Zn, Cu) bioactive glasses/composites, and Zn₂SiO₄ and CuO can be clearly detected on bioactive glass with high Zn contents and all of the Cu-containing bioactive glasses/composites, respectively. The MgO-substituted bioactive glasses/composites show the highest surface area among all MO-containing glasses/composites and the presence of crystallized phases of Zn₂SiO₄ and CuO in the ZnO- and CuO-containing bioactive glasses/composites lead to the decreased surface area and pore volume. The substitution of Ca with Mg, Zn or Cu inhibits the formation of HA deposition on the surface of the mesoporous bioactive glasses/composites, especially at high MO contents. The presence of MgO, ZnO and CuO slowed down the deposition rate of HA following a sequence of Cu < Mg < Zn. Therefore, the HA crystallite size and morphology can be easily tuned by the incorporation of Mg, Zn and Cu, which facilitates the wide application of the mesoporous bioactive glasses/composites.