The mechanical strength of metallic biomaterials supports their application in the fabrication of bone fixation plates and in development of scaffolds for bone tissue engineering.
The introduction of porosity into metallic scaffold structures provides void volume to enable cell migration and tissue formation, while promoting mechanotransduction with surrounding bone tissue. However, some topologies present stress risers that deleteriously affect the mechanical properties of the porous scaffolds. Advances in recent years in additive manufacturing technologies, such as 3D printing, enable realization of mathematical function-defined porous architectures with continuous curvature that may decrease stress risers. A recent article by Kelly et al. applied selective laser melting (SLM) technology to fabricate porous titanium structures with mathematical function-derived triply periodic minimal surfaces (TMPS). The authors investigated the effects of microarchitecture, such as wall thickness, and SLM laser parameters on the compressive and tensile mechanical properties, including fatigue behavior. The authors fabricated titanium scaffolds with porosity ranges comparable to trabecular bone and presenting mechanical properties within the range of trabecular and cortical bone. The authors demonstrated that the mechanical properties could be modulated through adjustment of the microarchitecture and the laser parameters. Overall, the article suggests the potential of additive manufacturing to enable fabrication of metallic scaffolds with porosities and mechanical properties tuned for bone tissue engineering applications. The implications of the work may extend more broadly to inform metallic implant design in craniofacial and orthopedic bone fixation applications, where mechanotransduction and osseointegration may be desired.
Fatigue behavior of As-built selective laser melted titanium scaffolds with sheet-based gyroid microarchitecture for bone tissue engineering.
Kelly CN, Francovich J, Julmi S, Safranski D, Guldberg RE, Maier HJ, Gall K. Acta Biomater. 2019;94:610-626.