Effect of boron incorporation on the bioactivity, structure, and mechanical properties of ordered mesoporous bioactive glasses

Author(s)

Deilmann, Leonie ^[1] ; Winter, Oliver ^[1] ; Cerrutti, Bianca ^[2] ; Bradtmueller, Henrik ^[2] ; Herzig, Christopher ^[3] ; Limbeck, Andreas ^[3] ; Lahayne, Olaf ^[4] ; Hellmich, Christian ^[4] ; Eckert, Hellmut ^{[2, 5]} ; Eder, Dominik ^[1]

Affiliation

^[1] Tech Univ Wien, Inst Mat Chem, Getreidemarkt 9-BC-02, A-1060 Vienna - Austria

^[2] Univ Sao Paulo, Inst Fis Sao Carlos, CEP 369, BR-13566590 Sao Carlos, SP - Brazil

^[3] Tech Univ Wien, Inst Chem Technol & Analyt, Getreidemarkt 9-164, A-1060 Vienna - Austria

^[4] Tech Univ Wien, Inst Mech Mat & Strukturen IMWS, Karlspl 13-202, A-1040 Vienna - Austria

^[5] WWU Munster, Inst Phys Chem, Corrensstr 28-30, D-48149 Munster - Germany

• Document type: Journal article
• Source: JOURNAL OF MATERIALS CHEMISTRY B; v. 8, n. 7, p. 1456-1465, FEB 21 2020.
• Web of Science Citations: 8

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. Si-29, B-11, P-31, and H-1 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. B-11[P-31] 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. (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