Corrosion Behavior and Osteogenic Activity of a Biodegradable Orthopedic Implant Mg-Si Alloy with a Gradient Structure

A gradient Mg-8 wt % Si alloy, which was composed of the agglomerated Mg2Si crystals coating (GMS8-1) and the eutectic Mg-Si alloy matrix (GMS8-2), was designed for biodegradable orthopedic implant materials. The bio-corrosion behavior was evaluated by the electrochemical measurements and the immersion tests. The results show that a significant improvement of bio-corrosion resistance was achieved by using the gradient Mg-Si alloy, as compared with the traditional Mg-8 wt % Si alloy (MS8), which should be attributed to the compact and insoluble Mg2Si phase distributed on the surface of the material. Especially, GMS8-1 exhibits the highest polarization resistance of 1610 omega, the lowest corrosion current density of 1.7 x 10(-6) A center dot cm(-2), and the slowest corrosion rate of 0.10 mm/year. In addition, GMS8-1 and GMS8-2 show better osteogenic activity than MS8, with no cytotoxicity to MC3T3-E1 cells. This work provides a new way to design a gradient biodegradable Mg alloys with some certain biological functions.

Automated summary

The gradient Mg-Si alloy designed for biodegradable orthopedic implant materials shows significant improvement in bio-corrosion resistance, with high polarization resistance, low corrosion current density, and slow corrosion rate. Additionally, the alloy exhibits good osteogenic activity and non-toxicity to cells.