Influence of ZnOAddition on the Structural and BiologicalProperties of Borate Bioactive Glasses for Bone Tissue Regeneration

This research evaluated the ZnO influence on the bioactivity of the vitreous system formulated as ((64-x) B2O3–2P2O5–18 CaO–16Na2O–xZnO, with x = 0, 1, 2.5, 5, 7.5, and 10 mol %). The glasses were synthesized by melt-quenching technique and characterized by density, molar volume, FTIR, N4, XRD, radiopacity, in vitro test in SBF, mass loss, SEM-EDS cellular viability, cell migration assay, and antibacterial activity. The volumetric density and N4 increased, and the molar volume decreased, indicating that the addition of ZnO changed the structure of the materials. DTA analysis showed that Tg did not vary significantly, Tx increased due to the ZnO addition, and all samples presented good thermal stability. The radiopacity level of the glass samples was enhanced with ZnO addition. Also, analyses of mass loss and pH measurements shown an increase in the chemical stability of samples with ZnO contents. After immersion in SBF, the XRD diffractograms and FTIR spectra of glasses indicated the bioactivity of the CaNaB, 2.5% ZnO, and 5% ZnO samples by the presence of peaks and bands characteristic of HA formation. By cell viability analysis using RAW-264.7 murine macrophages, all glasses were shown to be noncytotoxic. Bioactive glasses compositions preserve the intrinsic migratory capacity of human fibroblasts. All glass samples showed antibacterial activity against Gram-positive and Gram-negative bacteria. The results indicate the potential of glass samples for bone tissue regeneration.