Mechanical and Biological Properties of Fe-P Scaffolds Fabricated by Powder Metallurgy Method for Bone Tissue Engineering Applications

In this research, Fe-P scaffolds were successfully fabricated by the powder metallurgy method for the first time, using NaCl as the space holder for bone tissue engineering applications, with apparent porosities of approximately 70%. The Fe3P powder was successfully synthesized by the mechanochemical method under an argon atmosphere using an initial mixture of Fe and P powders. The XRD patterns show that Fe3P was obtained after sintering the milled powders at 1000 °C. Fe, Fe3P, and Fe-50 wt% Fe3P composite scaffolds and bulk pellets were prepared by sintering the milled powder at 1000 °C. Furthermore, the mechanical properties (compression strength) and bioactivity of the Fe-P scaffolds were determined. According to the compression test results, the composite scaffold showed higher compressive strength, lower fracture strain, and higher elastic modulus than the Fe and Fe3P scaffolds, indicating that adding Fe3P to Fe improves the mechanical properties. Moreover, among the scaffolds prepared by sintering at 1000 °C, the Fe scaffold exhibited the highest corrosion rate compared to the Fe3P and composite samples, while the corrosion resistance of the composite sample was 3 times higher than that of the Fe sample. The ICP analysis showed that the amount of Fe released from the bulk pellets during soaking in PBS solution after four weeks was 3220 μg/dL, 4003 μg/dL, and 4774 μg/dL for the composite, Fe3P, and Fe samples, respectively. The composite sample showed the highest cell viability, while the Fe sample had the lowest. The compressive strength (12.62 MPa) and fracture strain (5.98%) of the porous sintered composite scaffold at 1000 °C were within the range of trabecular bone, while the compressive strength of the composite sample was 17 times higher than that of the Fe sample. Furthermore, the MTS test showed that all the samples had good viability, while the composite sample had the best cell viability. The scaffolds were not cytotoxic. It can be concluded that the mechanical and biological properties of the composite sample were superior to those of the Fe and Fe3P samples and that it may be a promising candidate for bone tissue engineering applications, especially for trabecular bone replacement.