Effect of Ta2O5 content on the microstructural properties of 45S5 bioglass glass-ceramic scaffolds

Bioactive glasses are mainly used to repair bone defects since they stimulate the natural healing of damaged tissues, allowing the adhesion and proliferation of bone-forming cells. On the other hand, tantalum is known to have good chemical resistance and biocompatibility, with no adverse biological response in organisms. In the present work, 45S5 bioglass systems undoped and doped with Ta₂O₅ were prepared according to the following stoichiometric molar relationship (46 − x)SiO₂ − 26.9CaO − 24.4Na₂O − 2.6P₂O₅ − xTa₂O₅ (x = 0, 0.1, 0.5) by the conventional melt quenching technique. Subsequently, scaffolds from these glassy systems were prepared using the combined method of powder technology and polymer foaming. Both, glass powders and scaffolds, were physicochemical characterized. The results showed that the 0.5 mol% Ta₂O₅-doped scaffolds exhibited less contraction (36.53%) and higher porosity (84.24%) during sintering, with interconnected porosity, pore size in the range of 19–260 μm, and a greater surface area (17.431 ± 0.846 m²/g) than the scaffolds with no Ta₂O₅. Furthermore, the tantalum oxide promoted the formation of a sodium tantalum phosphate phase, along with the combeite and silicorhenanite present in the undoped-glass scaffolds. The maximum compressive strength of scaffolds ranged from 0.42 to 1.40 MPa and the elastic modulus (E) from 0.19 to 0.47 GPa.