Porous shape-memory scaffolds as mechanically active bone implants, FHNW School of Life Sciences

Our aim is to develop smart medical implants that interact with the surrounding bone tissue. We are investigating porous shape-memory structures as future implantable biomaterial with improved bone-tissue to implant interaction and therefore improved clinical outcome. Porous structures of the shape-memory alloy (SMA) nickel-titanium (NiTi) are created by additive manufacturing and tested in-vitro and in-vivo.

Using selective laser melting (SLM) we are fabricating SMA structures as scaffolds for tissue engineering applications and implants. The applied method allows the production of complex-shaped metallic structures based on a virtual CAD model. The interactions of the structures with progenitor cells as well as their response to three-dimensional structures are investigated within a novel bioreactor model system. This compression perfusion bioreactor serves as an in-vitro model for an orthotopic implantation site which allows for the testing of the NiTi scaffolds under physiological conditions.

The damping properties of NiTi are associated with the martensite-austenite phase transformation. The results indicate that selective laser melting of NiTi is suitable for the fabrication of medical implants with ultra-high mechanical damping capacity.

The behaviour of the porous structures opens unknown perspectives and adaptations of the biofunctionality. The novelty of this technology lies in the fact that implantable structures can be produced with predefined physical and mechanical properties that can be optimized for specific functions in the body. In particular, the porous SMA structures can be associated with a better performance in bone tissue.

• From powder to complex-shaped NiTi structures by selective laser melting
• Fabricating NiTi shape memory scaffolds by selective laser melting
• Crystallographic phases of NiTi scaffolds fabricated by selective laser melting
• Fatigue behaviour of selective-laser-melted nickel-titanium scaffolds
• FEM analysis of porous titanium bone scaffold
• Ni release from rapid prototyped 3D NiTi scaffolds
• Smart NiTi constructs for 3D cell culture applications
• Properties of NiTi-structures fabricated by selective laser melting