(595a) Self-Fitting, Shape Memory Polymer Scaffolds for Bone Defect Repair

Autografting is currently considered the gold standard in cranial bone defect treatment, yet procedures remain limited by the difficulty of shaping and fitting rigid grafts tightly within the defects. The resulting ill-fitting interface can lead to graft resorption and failure. Regenerative engineering could provide a promising alternative treatment but critically relies on a scaffold that is able to conformally “fit” within an irregular defect. Our group has proposed “self-fitting” bone tissue scaffolds based on poly(e-caprolactone) diacrylate (PCL-DA) that can be softened via exposure to warm saline and can then be easily press-fitted into bone defects with complex geometries. To accelerate the rate of scaffold degradation and encourage neotissue formation, we have formed these PCL-based scaffolds in conjunction with other polymers. For instance, scaffolds were prepared as semi-interpenetrating networks (semi-IPNs) comprised of “non-crosslinked” thermoplastic poly(lactic acids) (PLAs) within the “crosslinked” thermoset PCL-DA network. Siloxane-based polymers were formed as co-networks with PCL as well. The impact of composition on degradation rate and mechanical properties was evaluated. In addition, the ability of these SMP scaffolds to promote healing in calvarial defect models was also evaluated.