Investigating the influence of Na+ and Sr2+ on the structure and solubility of SiO2–TiO2–CaO–Na2O/SrO bioactive glass

Abstract

This study was conducted to determine the influence that network modifiers, sodium (Na+) and strontium (Sr2+), have on the solubility of a SiO2-TiO2-CaO-Na2O/SrO bioactive glass. Glass characterization determined each composition had a similar structure, i.e. bridging to non-bridging oxygen ratio determined by X-ray photoelectron spectroscopy. Magic angle spinning nuclear magnetic resonance (MAS-NMR) confirmed structural similarities as each glass presented spectral shifts between -84 and -85 ppm. Differential thermal analysis and hardness testing revealed higher glass transition temperatures (Tg 591-760 °C) and hardness values (2.4-6.1 GPa) for the Sr2+ containing glasses. Additionally the Sr2+ (~250 mg/L) containing glasses displayed much lower ion release rates than the Na+ (~1,200 mg/L) containing glass analogues. With the reduction in ion release there was an associated reduction in solution pH. Cytotoxicity and cell adhesion studies were conducted using MC3T3 Osteoblasts. Each glass did not significantly reduce cell numbers and osteoblasts were found to adhere to each glass surface.

The impact of gallium content on degradation, bioactivity, and antibacterial potency of zinc borate bioactive glass

“…The normalized EDS spectra of the synthesized glasses after incubation in SBF revealed that the calcium and phosphorus on the surface of the incubated glass powders increase with immersion time (Figure ). Similar trends have been reported for incubated bioactive glasses . The observed increase in the intensity of the Ca, P, and Zn peaks in the EDS spectra can be seen as an indication of formation of CaP layer, where Ca seems to be partially replaced by Zn; this partial replacement of Ca with Zn has been previously reported for other bioactive glasses with Zn in their composition .…”

“…SEM images of the powders after 24 h immersion in SBF showed precipitations on the surface for all five compositions (Figure ). The morphology of the observed precipitations is comparable to CaP and HA precipitations on bioactive glasses reported in the literature . The normalized EDS spectra of the synthesized glasses after incubation in SBF revealed that the calcium and phosphorus on the surface of the incubated glass powders increase with immersion time (Figure ).…”

“…Similar trends have been reported for incubated bioactive glasses. 34,[39][40][41] The observed increase in the intensity of the Ca, P, and Zn peaks in the EDS spectra can be seen as an indication of formation of CaAP layer, where Ca seems to be partially replaced by Zn; this partial replacement of Ca with Zn has been previously reported for other bioactive glasses with Zn in their composition. [42][43][44][45][46] Further analyses such as FTIR and XRD can provide more information about the chemical composition and crystallinity of the observed precipitations.…”

“…The morphology of the observed precipitations is comparable to CaAP and HA precipitations on bioactive glasses reported in the literature. 34,[39][40][41] The normalized EDS spectra of the synthesized glasses after incubation in SBF revealed that the calcium and phosphorus on the surface of the incubated glass powders increase with immersion time (Figure 4). Similar trends have been reported for incubated bioactive glasses.…”

A Novel Bioactive Glass Containing Therapeutic Ions with Enhanced Biocompatibility

“…Furthermore, SrO and MgO amounts were kept unchanged from the Bio_MS composition because such oxides have been shown to further contribute to decrease the glass transition temperature T g and increase the crystallization temperature T c [ 19 , 20 , 21 , 22 ]. Nonetheless, the incorporation of SrO and MgO not only aims to improve thermal properties but it also aims to enhance the biological performance; it has been reported that Sr and Mg ions improve effectiveness for bone regeneration [ 23 , 24 , 25 , 26 ] and cell proliferation [ 27 , 28 ].…”