Magnesium calcium silicate bioactive glass doped with copper ions; synthesis and in-vitro bioactivity characterization

Recent studies revealed that metallic ions have therapeutic effects on human bone metabolism and angiogenesis. Thus, in this study, a new magnesium-calcium-silicate glass powder, being doped with copper ions was synthesized through the sol-gel process; the material was termed as 60S7M2Cu. The glass was thermally treated at several temperatures up to 870 °C in order to induce crystallization, which would potentially enhance its mechanical and/or biological properties. Structural and morphological characterization, thermal analysis and in-vitro apatite forming ability evaluation were performed by X-ray diffraction-XRD, Scanning Electron Microscopy-SEM coupled with Energy Dispersion Spectrometry-EDS, Thermogravimetric Analysis, as well as Fourier Transformed Infrared-FTIR Spectrometry. Moreover, the elemental release was recorded by Inductively Coupled Plasma Atomic Emission Spectroscopy ICP-AES. Experimental results showed that a crystalline hydroxyapatite phase was developed after 3 days in the simulated body fluid (SBF) followed, after 15 days, by the growth of a carbon hydroxyapatite layer, in both untreated glass as well as treated glass-ceramics nearly at all temperatures. At lower temperatures, namely 770 and 800 °C, a whitlockite bioactive phase appeared after the immersion in SBF, while a wollastonite crystalline phase emerged when treated at 830 and 870 °C without having a negative effect on its apatite forming ability. Copper ions releasing from the glass and glass-ceramics materials was proved to be slow and stable during the whole period of soaking. In this study copper containing glass and glass-ceramics, which present apatite forming ability and according to literature possess the capability to induce the release of therapeutic ions with osteogenic and angiogenic capacity, were synthesized. Eventually, after further investigations, this glass composition could be applied in bone tissue engineering, where bioactive materials able to induce simultaneously both osteogenesis and angiogenesis constitute a constant demand.