Copper-doped and copper free bioactive glass nanopowders cytotoxicity and antibacterial activity assessment

The purpose of this study was to evaluate the antibacterial activity and cytotoxicity of copper-doped (Cu45SBG) and copper-free bioactive glass (45SBG) nanopowders. The antibacterial effect was studied using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus)bacteria. The BG nanopowders were synthesized by the sol-gel technique. Theywere characterized by various techniques and their cytotoxicity was evaluated by MTT assay. Chemical compositions of BGs were as the same as predicted compositions. The size of the BGs with an amorphous structure was measured around 100 nm. Both BG nanopowders have no antibacterial effect at broth concentrations less than 12.5 mg/ml. They demonstrated the similar antibacterial activity on E. coli with the minimum bactericidal concentration (MBC) of 12.5 mg/ml. Cu45SBG nanopowders with the MBC of 25 mg/ml were more efficient on S. aureous bacteria than 45SBG nanopowders with the MBC of 50 mg/ml. Cu45SBG showed much more cytotoxicity than 45SBG. The latter, demonstrated similar cells viability to the control. It was concluded that overcome cytotoxic effect, Cu content of BGs nanopowders must be lower than the amount which was used in this research. Therefore, 45SBG nanopowders with considerable antibacterial activity could be used as a good candidate for biomedical applications.