The role of titania on the microstructure, biocorrosion and mechanical properties of Mg/HA-based nanocomposites for potential application in bone repair

Bone defects are very challenging in orthopedic practice. The ideal bone grafts should provide mechanical support and enhance the bone healing. Biodegradable magnesium (Mg)-based alloys demonstrate good biocompatibility and osteoconductive properties, which are promising biomaterials for bone substitutes. However, the high rate of their biodegradation in human body environment is still challenging. For this scope, synthesis Mg-based composites with bioceramic additives such as HA and titania (TiO2) is a routine to solve this problem. The aim of this study was to evaluate the effect of addition TiO2 nanopowders on the corrosion behavior and mechanical properties of Mg/HA-based nanocomposites fabricated using a milling-pressing-sintering technique for medical applications. The microstructure of Mg/HA/TiO2 nanocomposites, in vitro degradation and biological properties including in vitro cytocompatibility were investigated. The corrosion resistance of Mg/HA-based nanocomposites was significantly improved by addition 15 wt% of TiO2 and decrease HA amount to 5 wt% this was inferred from the lower corrosion current; 4.8 µA/cm2 versus 285.3 µA/cm2 for the Mg/27.5 wt%HA, the higher corrosion potential; −1255.7 versus −1487.3 mVSCE, the larger polarization resistance; 11.86 versus 0.25 kΩ cm2 and the significantly lower corrosion rate; 0.1 versus 4.28 mm/yr. Compressive failure strain significantly increased from 1.7% in Mg/27.5HA to 8.1% in Mg/5HA/15TiO2 (wt%). The Mg/5HA/15TiO2 (wt%) nanocomposite possessed high corrosion resistance, cytocompatibility and mechanical properties and can be considered as a promising material for implant applications.