E164-01-2 - Forschungsgruppe Oberflächen-, Spurenanalytik und Chemometrie E165-02 - Forschungsbereich Molekulare Materialchemie E202-01 - Forschungsbereich Festigkeitslehre und Biomechanik E202-02 - Forschungsbereich Struktursimulation und Ingenieurholzbau
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Journal:
Journal of Materials Chemistry B: Materials for biology and medicine
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ISSN:
2050-750X
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Date (published):
9-Jan-2020
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Number of Pages:
10
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Peer reviewed:
Yes
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Keywords:
General Materials Science; General Medicine; Biomedical Engineering; General Chemistry
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Abstract:
B2O3 doped (0.5–15 mol%) ordered mesoporous bioactive glasses (MBG) with the composition 80% SiO2–15% CaO–5% P2O5 were synthesized via a sol–gel based evaporation-induced self-assembly process using the block-copolymer P123 as a structure directing agent and characterized by biokinetic, mechanical and structural investigations. Nitrogen physisorption isotherms and electron microscopy indicate no detrimental effect of B2O3 on the ordered hexagonal pore structure. Boron incorporation increases both the bulk modulus and hardness of the glasses. In vitro bioactivity tests reveal a rapid initial release of Ca2+ and PO43− ions, followed by formation of hydroxyapatite carbonate within a few hours. Contrary to the tight incorporation of Al in Al-doped MBGs, the rapid release of borate species into simulated-body-fluid suggests loosely bound species localized at the internal surfaces of the mesopores. 29Si, 11B, 31P, and 1H solid state NMR spectroscopy reveal that the majority of the borate is present as anionic BO4/2− species. The need for charge compensation leads to an increase in the average degree of polymerization of the phosphate species for high boron contents. 11B{31P} rotational echo double resonance NMR results reveal the absence of B–O–P linkages. This structural model explains the rapid release of borate and the enhanced dissolution kinetics of the Ca2+ and phosphate species.