Corrosion behavior and degradation mechanism of micro-extruded 3D printed ordered pore topological Fe scaffolds

The fabrication of ordered pore topological structures (OPTS) with an improved biodegradation profile offers unique attributes required for bone reconstruction. These attributes consisted of fully interconnected porous structure, bone-mimicking mechanical properties, and the possibility of fully regenerating bony defects. Most of the biomaterials based on magnesium were associated with the problem of too fast degradation rate. Here, the present aim was based on the fabrication of ordered pore topological Fe structures (OPTFS) using micro-extrusion-based 3D printing followed by pressureless microwave sintering. Two different kinds of pore features namely randomly distributed interconnected micropores and designed interconnected macropores were investigated. Static in vitro degradation results inferred that the H-2 mm pore size of hexagonal based ordered pore topological Fe structures (H-OPTFS) exhibited the highest degradation rate of 6.45 mg cm^-2  day^-1 on the 28th day. Electrochemical results revealed that the corrosion current density of the T-1 Fe sample with 44% porosity increased nearly by a multiple of three times as compared to dense Fe (from 16.79 to 44.63  $$_. Similarly, these results showed more significance in H-2 mm pores size (with highest 66% porosity) of H-OPTFS as compared to H-1.75 mm and H-1.5 mm pore size of H-OPTFS (≈2 times higher degradation rate than H-1.5 mm pore size). Moreover, the MG63 osteoblast cell line was adhered to and proliferated significantly throughout the surface and illustrated more than 80% cell viability of the prepared porous Fe scaffold. The analyzed results have shown the potential of fabricated OPTFS could be considered for biomedical applications.