Bioactive and Antibacterial Glass Powders Doped with Copper by Ion-Exchange in Aqueous Solutions

In this work, two bioactive glass powders (SBA2 and SBA3) were doped with Cu by means of the ion-exchange technique in aqueous solution. SBA2 glass was subjected to the ion-exchange process by using different Cu salts (copper(II) nitrate, chloride, acetate, and sulphate) and concentrations. Structural (X-ray diffraction-XRD), morphological (Scanning Electron Microscopy-SEM), and compositional (Energy Dispersion Spectrometry-EDS) analyses evidenced the formation of crystalline phases for glasses ion-exchanged in copper(II) nitrate and chloride solutions; while the ion-exchange in copper(II) acetate solutions lead to the incorporation of higher Cu amount than the ion-exchange in copper(II) sulphate solutions. For this reason, the antibacterial test (inhibition halo towards S. aureus) was performed on SBA2 powders ion-exchanged in copper(II) acetate solutions and evidenced a limited antibacterial effect. A second glass composition (SBA3) was developed to allow a greater incorporation of Cu in the glass surface; SBA3 powders were ion-exchanged in copper(II) acetate solutions (0.01 M and 0.05 M). Cu-doped SBA3 powders showed an amorphous structure; morphological analysis evidenced a rougher surface for Cu-doped powders in comparison to the undoped glass. EDS and X-ray photoelectron spectroscopy (XPS) confirmed the Cu introduction as Cu(II) ions. Bioactivity test in simulated body fluid (SBF) showed that Cu introduction did not alter the bioactive behaviour of the glass. Finally, inhibition halo test towards S. aureus evidenced a good antimicrobial effect for glass powders ion-exchanged in copper(II) acetate solutions 0.05 M.