[Zurück]

S. Melchers, T. Uesbeck, O. Winter, H. Eckert, D. Eder:
"Effect of Aluminium Ion Incorporation on the Bioactivity and Structure in Mesoporous Bioactive Glasses";
Chemistry of Materials, 28 (2016), 10; S. 3254 - 3264.

This work is dedicated to biokinetic and structural investigations of Al2O3 doping (0.5 to 15 mol %) in ordered mesoporous bioactive glasses (MBG), 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 27Al(31P) 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).

bioactive glasses mesopores block-copolymers doping solid-state NMR

http://dx.doi.org/10.1021/acs.chemmater.5b04117

http://publik.tuwien.ac.at/files/PubDat_251324.pdf