Material Selection & Design for Lattice-Based Biodegradable Metal Implants for Bone Regeneration in Load-Bearing Bone Defects
Human bone is a dynamic tissue and has a natural ability to repair small fractures quickly; however, critical fractures below the waist require external mechanical aids to help bear loading while healing. These techniques are effective but tend to cause a lack of mobility and decrease quality of life. New materials focused on the biodegradability of implants have opened new avenues in implant design and fabrication, reducing previous concerns such as tunability of degradation rates in such materials. Furthermore, three-dimensional (3D) printed biodegradable metallic implants show promise as an alternative for expediting recovery and increasing mobility, especially with the growth of lattice-based design and better osseointegration techniques. This study discusses the development and testing of a functional AM implant that integrates load-bearing, biodegradability, biocompatibility, and osseointegration, with an eye toward clinical translation. Based on the desired material properties, an iron-manganese mixture is used, along with dopants to aid biocompatibility and improve degradation rates. Lattice-based design has been implemented to reduce material usage without affecting mechanical properties, and the implants have been printed using binder jetting. After fabrication, experiment analysis to evaluate mechanical properties, degradation rates and byproducts, in-vitro performance, and microstructure has been performed for validation, to prepare the implant for in-vivo testing, giving us a functional lattice-based biodegradable metal implant.