Fabrication and Characterization of Highly Porous Gyroid Scaffolds Composed of Deproteinized Bone Mineral

Current treatment methods for critical bone defects involve the implantation of large bone grafts, which are limited by tissue availability and failure to heal correctly with high complication rates. Bioengineered scaffolds have emerged, which deploy biodegradable, highly osteoconductive materials in porous structures to accommodate the high mass transport requirements of large bone defects. Ideal scaffold biomaterials require a balance between strength, composition, and osteoconduction, a balance which has yet to be discovered. Naturally derived materials like deproteinized bovine bone mineral (DBBM) have seen successful clinical use for decades as bone void fillers, but their granular or putty form lacks the interconnected porosity required to treat large defects. Leveraging the clinical success of DBBM, this paper presents the first fabrication of highly porous scaffolds composed of naturally derived, deproteinized bone mineral, for potential use in large bone defects. Ovine bone mineral powder was prepared from fresh ovine bone, fabricated into a photopolymeric slurry and 3D-printed using a photocasting process into 67% porous gyroid scaffolds. Ovine bone mineral composition, surface microstructure, compressive properties, and failure probability were evaluated and compared to gyroid scaffolds composed of tricalcium phosphate. Both scaffold types were similar, with characteristics in the low range of human cancellous bone.