Effect of Aluminum Ion Incorporation on the Bioactivity and Structure in Mesoporous Bioactive Glasses

Author(s)

Melchers, S. ; Uesbeck, T. ; Winter, O. ; Eckert, H. ; Eder, D.

• Document type: Journal article
• Source: CHEMISTRY OF MATERIALS; v. 28, n. 10, p. 11-pg., 2016-05-24.

Abstract

work is dedicated to biokinetic and structural investigations of Al2O3 doping (0.5 to 15 mol %) in ordered mesoporous bioactive glasses (MBGs), based on the composition 80% SiO2-15% CaO-5% P2O5 (in mol %). The synthesis was performed with the sol gel method in combination with a structure directing agent (P-123) for the formation of mesopores. Structural investigations reveal that the incorporation of additional Al2O3 in a range of 1 to 10 mol % reduces the order of the mesostructure, whereas doping with 15 mol % Al2O3 creates well ordered mesopores again. Nitrogen adsorption-desorption isotherms show that specific surface area, pore volume, and pore diameter decrease only slightly upon incorporation of Al2O3. In vitro bioactivity tests exhibit a small decrease in bioactivity upon incorporation of small amounts and a sudden drop beyond 3 mol %. This can be related to the strong interaction of Al3+ and PO43-, which could be proven by multinuclear single and double resonance solid state nuclear magnetic resonance (NMR) spectroscopy. The number of P-O-Al linkages has been estimated by Al-27(P-31) rotational echo double resonance (REDOR) experiments. The interaction of Al3+ and PO43- and the trapping of Ca2+ required for charge compensation hamper the release of P, Ca, and Si ions and thus provide less PO43- and Ca2+ ions for the crucial formation of hydroxycarbonate apatite (HCA). (AU)

• FAPESP's process: 13/07793-6 - CEPIV - Center for Teaching, Research and Innovation in Glass
• Grantee: Edgar Dutra Zanotto
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC