Ion release from SrO-CaO-TiO2-P2O5 glasses in Tris buffer solution

Abstract

SrO-containing calcium phosphate invert glasses, (60-x)CaO•xSrO•30P2O5•7Na2O•3TiO2 (mol%, x = 0 -60), which are expected to inhibit bone resorption by osteoclast and enhance bone formation, were prepared and their ion release behaviors in Tris buffer solution were estimated. The glass containing 20 mol% of SrO showed the smallest amount of the dissolved ions in the present work. Laser Raman spectra showed that the peaks of phosphate groups and TiOy polyhedral groups red-shifted with increasing the SrO content in the glasses. The shift was suggested to be due to decrease in bonding strength between cations and phosphate groups or TiOy polyhedral groups in the glasses. In the case of the glasses containing SrO over 20 mol%, no shifts of Raman peaks due to the TiOy polyhedra were observed. The TiOy (y = 4 or 6) polyhedra in the glasses can coordinate with cations up to 18 mol% since they contain 3 mol% of TiO2. Sr 2+ ions are supposed from the shift behavior of the Raman peaks to preferentially coordinate with the TiOy polyhedra; the formation of this structure would induce decrease in the ion amounts released from the glasses containing 0 -20 mol% of SrO.

Structural and physico-chemical analysis of calcium/strontium substituted, near-invert phosphate based glasses for biomedical applications

“…[60,61]. This, correlated with the observation that the calcium free (Sr16) glass composition had to be cooled much more rapidly than the others to form a glass, agrees well with the work of Lee et al [61,62] who observed that a higher tendency of crystallisation occurred with increasing SrO content in a 30P 2 O 5 ·7MgO·3TiO 2 ·(60-x)CaO·xSrO and 30P 2 O 5 ·7Na 2 O·3TiO 2 ·(60-x)CaO·xSrO (mol %) glass system where x is 0-60. The narrowing of the thermal processing window with increasing SrO, may potentially make thermal post processing (such as extrusion and fibre drawing) of high strontium content phosphate glasses more difficult than for lower strontium containing formulations.…”

“…9) is lower for the mixed Sr/Ca compositions compared to the rate for the single cation glasses (P40 and Sr16) suggests a mixed mobile ion (MMI) effect [101]. [62]. This in turn would increase packing density and so decrease dissolution and hence ion release rates.…”

Effect of Partial Crystallization on the Structural and Luminescence Properties of Er3+-Doped Phosphate Glasses

“…The bands at around 700 cm −1 and at 1025 cm −1 correspond to the symmetric stretching bridging ν sym (O-P-O) of Q 2 groups and to the symmetric stretching ν sym (P-O) of terminal Q 1 groups, respectively [35]. The bands at 1170 and 1280 cm −1 can be ascribed to the symmetric and asymmetric stretching of non-bridging ν(PO 2 ) of Q 2 groups, respectively [36,37,38]. This spectrum clearly shows the typical structure of a metaphosphate glass [39].…”

Processing and characterization of novel borophosphate glasses and fibers for medical applications

“…The spectra exhibit bands at~690, 1010, 1175 and 1250 cm −1 and one shoulder at 1095 cm − 1 . The bands at around 1230 and 1175 cm −1 can be ascribed to the asymmetric and symmetric stretching of non-bridging ν(PO 2 ) of Q 2 groups, respectively [29][30][31]. The band at 1020 cm −1 can be related to the stretching ν(P-O) of terminal groups (Q 1 ) and the band at 690 cm −1 to the symmetric stretching of bridging ν s (O-P-O) of Q 2 groups [32].…”