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Fabrication and Mechanical Testing of Nitinol Scaffolds Regeneration of Bone
Puja Ruparel
Mentor: James Earthman
Osteoporosis causes bone to become porous and weak while also adversely affecting bone-healing
mechanisms. The healing process of bones is generally improved with the application of a structural
guide to keep the damaged bone in place and provide for the greater mechanical stimulation
necessary for bone growth processes. Porous scaffold implants have been used for this physical
guidance and stimulus. A Nitinol® mesh is being developed as a porous scaffold structure.
Polylactide-co-glycolide (PLGA). A biodegradable polymer is also being explored as an external
containment layer for the Nitinol mesh. In addition, particles of hydroxyapatite (HAP), a bioactive
ceramic, will be incorporated in the microstructure of the PLGA. The shape memory properties of
the Nitinol mesh allow it to expand to the desired shape and size following surgical placement as the
temperature rises due to body heat in vivo. The expansion of the Nitinol will exert pressure on the
PLGA/HPA layers which should then exert pressure on the surrounding bone triggering osteoblasts
and osteoclasts to start the bone repair process. The purpose of this research is to explore how
Nitinol wire meshes can be fabricated and compressed to a sufficiently small size for minimally
invasive surgical placement, and then expanded to fill the bone wound at physiological temperatures.
Another objective is to determine how much mechanical stimulus the mesh will transmit to the
surrounding bone as a function of mesh structure.