Mesoporous Carbon as Galvanic-Corrosion Activator Accelerates Fe Degradation

Iron (Fe) has attracted intensive attention as a bone implant material because of its inherent biodegradability, favorable biocompatibility and mechanical properties. Nevertheless, it degrades too slowly in a physiological environment, which limits its further clinical application. In this work, mesoporous carbon (MC) was introduced into Fe bone implant manufactured via a laser-additive manufacturing process. Particularly, MC possesses a noble standard corrosion potential and excellent electrical conductivity, thus acting as an effective cathode and activating micro-galvanic corrosion in the Fe matrix. More importantly, its high specific surface area enhanced the area ratio between cathode and anode, which further enhanced the galvanic corrosion effect. As a consequence, the corrosion rate was enhanced from 0.09 to 0.24 mm/year based on immersion tests. Besides, Fe/MC composite exhibited good cytocompatibility, as well as excellent mechanical properties. The positive results proved that the Fe/MC composite shows great potential as a bone implant.