Exploring the Role of Manganese on the Microstructure, Mechanical Properties, Biodegradability, and Biocompatibility of Porous Iron-Based Scaffolds

In this work, the role that manganese plays in determining the structure and performance of sintered biodegradable porous Fe–Mn alloys is described. Powder metallurgy processing was employed to produce a series of biodegradable porous Fe- x Mn ( x = 20, 30, and 35 wt %) alloys suitable for bone scaffold applications. Increasing manganese content increased the porosity volume in the sintered alloys and influenced the ensuing properties of the metal. The Fe-35Mn alloy possessed optimum properties for orthopedic application. X-ray diffraction analysis and magnetic characterization confirmed the predominance of the antiferromagnetic austenitic phase and ensured the magnetic resonance imaging (MRI) compatibility of this alloy. The porous Fe-35Mn alloy possessed mechanical properties (tensile strength of 144 MPa, elastic modulus of 53.3 GPa) comparable to human cortical bone. The alloy exhibited high degradation rates (0.306 mm year –1 ) in simulated physiological fluid, likely due to its considerable Mn content and the high surface area inherent to its porous structures, while cytotoxicity and morphometry tests using mammalian preosteoblast cells (MC3T3-E1) indicated good cell viability in the Fe-35Mn alloy.