Low Cost Strontium Silicate Nanoceramics Prepared in Water Glass Medium for Bone Tissue Repair: in Vitro Studies

This study aims to develop alternative economic materials for bone tissue repair. Bioactive material was prepared through the nominal composition of strontium silicate Sr0.5(Ca, Mg)0.5SiO3 with partial replacement of Sr0.5 with Ca0.5 or Mg0.5. Differential thermal gravimetery (DTG), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Transmission electron-microscope (TEM), Scanning electron-microscope (SEM/EDX) and nano-Zetasizer were utilized to evaluate their properties. Moreover, the in vitro assessments such as bioactivity, antimicrobial activities, cell compatibility (cell death mode) and alkaline phosphatase activity (ALP) against MG-63 cell line were also performed. Sr- silicate (SrSiO3), wollastonite (CaSiO3), enstatite (MgSiO3) and cristobalite (SiO2) were developed through the sintering process at 900 degrees C/2h. The microstructure shows nanoparticles of the later phases through TEM analysis whereas it accumulated in clusters that indicated by SEM photographs. Also, the zeta potential confirmed that all the nanoceramic particles carry negative charges on their surfaces. The in vitro results of the sintered specimens indicated a great progress in formation of apatite in nano-size scale, through the SEM/EDX microanalysis. However, the antimicrobial properties proved the superiority, of Ca- or Mg-free SrSiO3 sample, against tested microorganisms. Moreover, all nanoceramics demonstrated excellent cell viability. However, the concentrations between 6.25 and 100 mu g/ml in the range of (97 to 121) showed the highest viability percentages. These findings supported the beneficial effects of Si and transition metals (strontium, calcium, and magnesium) on cell survival. In addition, ALP results confirmed a good cells differentiation, which obviously revealed in SrCS sample. These results suggested that silicate ceramics prepared in this study and doped with selected transition metals are applicable to regenerate bone tissue.