Bioactive antibacterial borate glass and glass-ceramics

•The influence of thermal treatment on the bioactivity of borate glasses was investigated.•The results after SBF immersion show the conversion of the glasses into HA e FA.•The addition of Ag2O did not influence the in vitro bioactivity of the samples.•Bactericidal effect against E.coli and bacteriostatic activity against S. aureus was verified.•The crystallization does not inhibit bioactivity of the samples. This work aimed to study bioactive glass-ceramics obtained by controlled crystallization, as a function of the heat treatment time, in system 59.5B2O3-2P2O5-9.5CaO-19.5Na2O-9CaF2-0.5Ag2O (mol %). The samples were prepared by the melt-quench method, and thermally treated at 530 °C, with different times: 0, 4, 8, 12, 24 and 36 h. Results of DTA, XRD, FTIR, density and molar volume are shown. The results of XRD revealed the development of crystalline phases during the heat treatment (CaNaB5O9, Ca3(PO4)2, Na2B6O10 and Ag°). The percentage of crystallization and in the size of the crystallite show increases with the time of the heat treatment, as expected. In vitro bioactivity of the samples was analyzed by immersion in SBF for 7, 14, 21 and 28 days. XRD patterns and FTIR spectra after immersion proved HA precipitation. The pH results reveal a higher ion exchange rate for the crystallized samples. This can be associated with the microstructure changes that occur on the surface of the samples during the heat treatment and the solubility of the crystalline phases. In addition, glass and crystallized samples showed antibacterial action against E. coli, independently of the crystallization time. It is possible to conclude that glass-ceramics can potentially be used as biomaterials in the treatment of bone fractures.