A dual redox system for enhancing the biodegradability of Fe-C-Cu composite scaffold

Fe-based biocomposites are emerging as temporary orthopedic implants due to natural biodegradability and high mechanical strength. Yet, the slow degradation kinetics restricts their biomedical applications. In this work, Cu-initiated redox system was established to accelerate the biodegradation of Fe-C composite scaffold prepared by selective laser melting. On the one hand, Cu induced micro-galvanic corrosion with Fe matrix due to their differences in potentials, accelerating the electron separation from Fe and further the dissolution of Fe matrix. On the other hand, Cu, as a good conductor of electron transfer, reduced the electron transfer impedance and increased the corrosion current density in Fe/C micro-galvanic cells. Consequently, the degradation rate of Fe-C scaffold was increased by 69% from 0.16 mm/y to 0.27 mm/y in the immersion tests. Additionally, the composite scaffold exhibited compression strength of 128 MPa and hardness of 148 HV, respectively. After co-culturing with the composite scaffold, MG-63 cells presented classical fusiform shape and good cell viability, indicating favorable biocompatibility. These results showed the potential applications of the developed redox systems as highly efficient initiator in accelerating the biodegradation of Fe-based biocomposites.