Effect of Ta2O5 nanoparticles on bioactivity, composition, structure, in vitro and in vivo behavior of PEO coatings on Mg-alloy

The present study investigates the physical and chemical characteristics, behavior in vitro and in vivo, and biocompatibility of coatings containing Ta2O5, which are obtained by plasma electrolytic oxidation (PEO) on MA8 magnesium alloy. The obtained coatings demonstrate in vivo biocompatibility and in vitro bioactivity. Compared to the base PEO coating, the layers containing Ta2O5 facilitate the development of apatite in simulated body fluid, suggesting that the inclusion of nanoparticles improves bioactivity of the coatings. It was found that incorporation of Ta2O5 nanoparticles increases roughness and porosity of the formed layers by increasing particle concentration in electrolytes for the PEO process contributing to sufficient soft tissue ingrowth in vivo. Based on in vivo studies, these coatings also provide favorable tissue response and minimal inflammatory reaction in comparison with the bare magnesium alloy due to protection of living tissues from deleterious corrosion events of magnesium implant such as local alkalization and intense hydrogen evolution. The results obtained in the present study concluded biocompatibility, tissue integration of the PEO coatings containing Ta2O5 nanoparticles making them a promising protective layer for biodegradable magnesium implants.