ESTUDO DA INFLUÊNCIA DO ÓXIDO DE ZINCO NA BIOATIVIDADE DE VIDROS CÁLCIO-SÓDIO-BORATOS

Abstract

The occurrence of defects in bone tissues resulting from accidents, diseases and aging is increasingly common. Similarly, injuries to epithelial tissues often occur resulting from factors such as: burns, abrasions, cuts and ulcers. Metalic ions as Zn2+ can be added to borate glasses to improve their bioactive properties, once this ion has feature of stimulating osteogenesis, wound healing and antibacterial action. In this research, vitreous samples containing ZnO with concentration of 0-10 mol% ((64-x) B2O3–2P2O5–18 CaO–16Na2O–xZnO, x= 0, 1, 2.5, 5, 7.5 e 10 mol %)) were synthesized by the melt-quenching technique in order to confirm bioactivity and potential for application in the hard and soft tissues regeneration. An increase in density and decrease in molar volume were observed with the replacement of B2O3 by ZnO indicating that the addition of ZnO modified the structure of the materials. The results of differential thermal analysis (DTA) showed an increase in crystallization onset temperature (Tx) and thermal stability with increasing zinc insertion in the samples. By cell viability analysis, all glasses were shown to be non-cytotoxic. The diffractograms of samples confirmed their amorphous character and FTIR spectra showed characteristic bands of borate glasses. The radiographs showed that the samples are radiopaque and that the level of radiopacity increased as the ZnO concentration increased. The glasses were immersed in SBF for 7, 14, 21 and 28 days to attest their bioactivity. The pH values of SBF showed that there was a decrease in ionic exchange rate between the material and the SBF with the increasing addition of ZnO. The addition of ZnO increased the chemical stability of samples, which was observed by the decrease in their degradation rate, this behavior was indicated by the analysis of mass loss of glass samples after all periods of immersion in SBF. The DRX diffractograms and FTIR spectra of glasses after immersion in SBF indicated the bioactivity CaNaB, 2.5% ZnO and 5% ZnO samples by the presence of peaks and bands characteristic of HA formation. All vitreous samples showed antibacterial activity against Gram positive and negative bacteria. The results indicate the potential of vitreous samples for use in bone tissue regeneration and possible use in soft tissue regeneration.