3D Printed Fe Scaffolds with HA Nanocoating for Bone Regeneration.

Pure iron (Fe) has been investigated as a cardiovascular stent in recent years for its biodegradation property and blood compatibility. It also has great potential for bone healing, especially for load-bearing areas based on its inherent mechanical property which is high enough for bone regeneration. However, the conventional manufacturing methods restrict its application as bone scaffold for uncontrollable architecture and stiffness. Also, the cytotoxicity makes it impossible for in vitro culture as bone tissue engineering scaffold. To solve these deficiencies, in the present study, we applied 3D printing technique with a modified coating strategy together to precisely control the macropore structure and surface nanostructure of final scaffolds. Our results showed that the compressive mechanical properties of the 3D printed Fe scaffolds were in the natural bone range and the hydroxyapatite (HA) coating was highly bonded to the substrate, significantly improved the viability and alkaline phosphatase (ALP) activity and osteogenic differentiation of the rabbit bone marrow mesenchymal stem cells (rBMSCs) on the scaffold. This study indicates that the 3D printed Fe scaffolds with controllable nanostructured HA coating may be a promising candidate for bone tissue engineering applications.