Designed Biodegradable and Osteoconductive Porous Scaffolds for HumanTrabecular Bone.

Bone Tissue Engineering;Scaffold;Solid Freeform Fabrication;Biodegradable;Biomineral Coating;Biomedical Engineering;Engineering;Biomedical Engineering

Saito, EijiTakayama, Shuichi ;

University of Michigan

关键词: Bone Tissue Engineering;    Scaffold;    Solid Freeform Fabrication;    Biodegradable;    Biomineral Coating;    Biomedical Engineering;    Engineering;    Biomedical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/89789/esaito_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Current bone graft substitutes, such as calcium phosphate and metals, do not have proper mechanical properties to match native bone tissues and/or permanently stay in the body, which leads to stress shielding and chronic inflammation.As an alternative approach, synthetic biodegradable polymer scaffolds, including Poly (lactic-co-glycolic acid) (PLGA), poly (L-lactic acid) (PLLA) and poly (ε-caprolactone) (PCL), have been developed using conventional fabrication techniques, such as porogen leaching and phase separation techniques.However, these scaffolds still have some limitations, including poor mechanical properties, poorly interconnected porous architectures, and lack of osteoconductivity.We developed osteoconductive porous biodegradable scaffolds using indirect solid freeform fabrication (SFF) and a biomineral coating techniques to match bone properties and enhance bone formation. First, two designs of 50:50PLGA scaffolds were fabricated that achieved mechanical properties within those of human trabecular bone.Micro-computed tomography (µ-CT) data confirmed that the fabricated scaffold architectures matched the designs.The µ-CT data was further utilized to computationally simulate scaffold mechanical properties using a voxel-based finite element method.Secondly, the effect of scaffold architectures and materials on bone formation was examined.Three types of scaffolds were designed and fabricated using 50:50PLGA and PLLA, and bone formation in the scaffolds were tested in vivo.50:50PLGA scaffolds did not support bone formation/ingrowth into scaffolds due to their rapid degradation, while PLLA scaffolds maintained their architectures and supported bone ingrowth.However, there was no effect of scaffold pore architecture on bone formation.Thirdly, we examined the effect of PLLA scaffolds architectures on long term in vivo degradation. We found that the scaffolds’ degradation rates were determined by their initially designed architectures.Lastly, to achieve better bone formation on and into scaffolds, PLLA and PCL scaffolds were coated with calcium phosphate biomineral layers using a modified simulated body fluid technique.In vivo data showed that the biomineral coated scaffolds had improved bone ingrowth compared with the uncoated scaffolds.Furthermore, advanced bone ingrowth supported mechanical properties of the coated PLLA scaffolds.Overall, this study provides beneficial information to develop bone scaffolds with enhanced bone formation as well as controlled scaffold degradation for craniofacial, orthopaedic and spinal applications.