Synthesis, in vitro evaluation and biological studies of copper-containing 58S bioactive glass

Cu-substituted 58S bioactive glasses (0-10%mol CuO) were synthesized by sol-gel method and the effect of copper substitution for calcium on their biodegradability, bone-like apatite formation, cell proliferation, alkaline phosphatase activity of M3T3-E1 osteoblast cells and antibacterial efficiency were investigated. The results of x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) and surface analysis using SEM confirmed the formation of a layer of bone-like apatite on the BGs after 7 days of immersion in SBF. The surface analysis with SEM indicated that the addition of copper to the structure led to a reduction of the amount of apatite formed on the surface. The evaluation of cellular response by MTT assay and alkaline phosphatase activity showed that the proliferation and differentiation of MC3T3-E1 cells in 58S BG substituted with 5 mol% CuO had the highest value compared to other samples while, the substitution of 10 mol% CuO in composition led to a reduction in cell proliferation and differentiation and induction of cell cytotoxicity. In addition, Cu-substituted glasses showed significant antibacterial effect against Escherchia coli (E.coli) and Staphylococcus aureus (S.aureus) bacteria so that the antibacterial activity coefficient against E.coli in 58S containing 5 mol% CuO has doubled compared to base glass and was more than 99% (p<0.01). Taken together, 58S glass containing 5% mol CuO has been recommended for use in repair of bone defects in tissue engineering due to its in vitro bioactivity, stimulation of MC3T3-E1 cell proliferation and differentiation and excellent antibacterial activity.