LAUSR

Abstract In this work silica-based bioactive glass powders were doped with Cu++ ions by means of ion-exchange process and subsequently they were exposed to different chemical (tannic acid, ascorbic acid and NaOH) and physical processes (UV irradiation, thermal treatment in air or argon atmosphere) to promote the in situ reduction of Cu++ ions to Cu+ or Cu0. The obtained glasses were investigated by means of structural (X-Ray diffraction – XRD), morphological and compositional analyses (scanning-transmission electron microscopy equipped with energy dispersive spectroscopy (FESEM/STEM-EDS); moreover, glasses were subjected to in vitro bioactivity test in simulated body fluid up to 14 days to investigate the influence of the performed chemical and physical treatments on glass bioactivity. At the end of incubation time glasses were analyzed by means of FESEM-EDS and Fourier transformation infrared spectroscopy (FT-IR). The obtained results evidenced that, in general, the chemical treatments are useful to induce the formation of Cu0, while thermal treatment induce the nucleation of CuO (in air) or Cu2O (in argon). All samples maintained a bioactive behavior. At least, preliminary antibacterial effect evaluation by inhibition halo test evidenced that samples containing free Cu++ ions or Cu0 nanoparticles possess the best antibacterial effect.