Mechanical and in vitro degradation behavior of magnesium-bioactive glass composites prepared by SPS for biomedical applications.

In order to make magnesium (Mg) a successful candidate for fracture fixation devices, it is imperative to control the corrosion rate and enhance its elastic modulus. In the present work, we have prepared bioactive glass (BG) reinforced magnesium composite using spark plasma sintering (SPS). Simultaneous application of heat and pressure during SPS decreased the softening point of BG (600°C), allowing it to coat the Mg particles partially. As a result, BG was found along the Mg particle boundaries, which was confirmed by elemental mapping. Addition of BG improved microhardness and elastic modulus of Mg-BG composites. Corrosion behavior was studied by hydrogen evolution and immersion corrosion in phosphate buffered saline (PBS). After 64 h of immersion, Mg-10 wt % BG composite showed highest corrosion resistance. Quantitative micro-computed tomography (micro-CT) results indicated porosity increase in Mg-BG composites during immersion. The maximum increase in porosity (1.66%) was noticed for pure Mg while the minimum for Mg-10 wt % BG composite. MG63 cell-material interactions, using extract method, showed good cytocompatibility for Mg-10 wt % BG composite. The concentration of Mg ion in cell culture media was measured using atomic absorption spectroscopy after 24 h immersion of Mg/BG composites. The results indicated that using BG as reinforcement and SPS as sintering method; we can prepare corrosion resistant and high modulus Mg-BG composites that can be used for fabricating bone fracture fixation plates.