31P MAS-NMR spectra were measured for pulverized binary and ternary glasses containing Ca2+ ions after soaking in a simulated body fluid (Kokubo solution; pH = 7.25) for 1 d, and the chemical state of adsorbed phosphate ions were examined. The 31P chemical shift indicated that orthophosphate ions, HxPO4-(3-x) (0<x<3), were adsorbed on all the glasses but 60CaO·40Al2O3; pyrophosphate ions, HzP2O7-(4-z), were detected on the aluminate glass, indicating that orthophosphate ions in the Kokubo solution were dimerized on the glass surface. For the glasses such as 60CaO·40Al2O3, 40CaO·60B2O3, 40CaO·30B2O3· 30Al2O3 and 40CaO·30B2O3·30SiO2, those phosphate ions gave broad 31P MAS-NMR spectra, hence have a broad distribution by coordinating to the various surface sites of the glasses. On the other hand, sharp 31P MAS-NMR spectra as for a cortical bone (rabbit) were obtained for the rest of the glasses, 50CaO·50SiO2 and 40CaO·30B2O3·30TiO2, on which apatite formed in shorter soaking period in the Kokubo solution. It was thus concluded that presence of orthophosphate ions on the glass surfaces favored the deposition of apatite.
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry