3D Printing of Biomaterials for Cranial Bone Tissue Engineering

Successful materials design for bone tissue engineering requires an understanding of the composition and structure of native bone tissue, as well as appropriate selection of biomimetic natural or tunable synthetic biomaterials, such as polymers, bioceramics, and composites. Scalable fabrication technologies that enable unparalleled control over construct architecture, such as 3D printing, can then be employed to process these biomaterials into suitable forms for bone tissue engineering. In this dissertation, an overview of materials design considerations for bone tissue engineering applications is provided. Additionally, demonstrated approaches for addressing the requirements of 3D printing with growth factors, including direct inclusion of growth factors with the biomaterial during printing or intermediary encapsulation of growth factors in delivery vehicles such as microparticles or nanoparticles, are described. Specifically, the 3D printing temperature is correlated to the bioactivity of osteogenic growth factor released from polymeric constructs. The effects of particulate delivery vehicle loading on 3D printing accuracy and scaffold degradation are also characterized. Subsequently, scaffolds composed of different ratios of β-tricalcium phosphate to hydroxyapatite were characterized for calcium and phosphate ion release under aqueous conditions, and for autologous bone-forming capacity in vivo in a rat bone augmentation model involving implantation of 3D printed bioceramic scaffolds against the calvarial periosteum. Finally, unmet needs and current challenges in the development of ideal materials for bone tissue regeneration are discussed, and emerging strategies in the field of bone tissue engineering are highlighted