Molecular Mass‐Dependent Resorption and Bone Regeneration of 3D Printed PPF Scaffolds in a Critical‐Sized Rat Cranial Defect Model

• Published in: Advanced healthcare materials 2019-09, Vol.8 (17), p.e1900646-n/a
• Main Authors: Nettleton, Karissa, Luong, Derek, Kleinfehn, Alex P., Savariau, Laura, Premanandan, Christopher, Becker, Matthew L.
• Format: Article
• Language: English
• Subjects: 3D printing; Biocompatibility; Bone growth; Bone mass; bone regeneration; Bone resorption; Computed tomography; cranial defects; Defects; degradation; Dental prosthetics; Formulations; Inflammation; Inflammatory response; Lamellar bone; poly(propylene fumarate); Polypropylene fumarate; Regeneration; Regeneration (physiology); Resins; Scaffolds; Skull; Surgical implants; Three dimensional printing
• ISSN: 2192-2640; 2192-2659
• DOI: 10.1002/adhm.201900646

The emergence of additive manufacturing has afforded the ability to fabricate intricate, high resolution, and patient‐specific polymeric implants. However, the availability of biocompatible resins with tunable resorption profiles remains a significant hurdle to clinical translation. In this study, 3D scaffolds are fabricated via stereolithographic cDLP printing of poly(propylene fumarate) (PPF) and assessed for bone regeneration in a rat critical‐sized cranial defect model. Scaffolds are printed with two different molecular mass resin formulations (1000 and 1900 Da) with narrow molecular mass distributions and implanted to determine if these polymer characteristics influence scaffold resorption and bone regeneration in vivo. X‐ray microcomputed tomography (µ‐CT) data reveal that at 4 weeks the lower molecular mass polymer degrades faster than the higher molecular mass PPF and thus more new bone is able to infiltrate the defect. However, at 12 weeks, the regenerated bone volume of the 1900 Da formulation is nearly equivalent to the lower molecular mass 1000 Da formulation. Significantly, lamellar bone bridges the defect at 12 weeks with both PPF formulations and there is no indication of an acute inflammatory response. The molecular mass variation between two scaffolds made from poly(propylene fumarate) and printed by stereolithography is investigated to elucidate the influence on bone regeneration in a rat critical‐sized cranial defect. The lower molecular mass polymer scaffold in this study facilitates a faster regeneration of bone at 4 weeks in vivo.