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Patient-specific orthopedic implant design and production with tissue engineering method

Büyüksungur, Senem
Customized and patient specific, tissue engineered constructs are needed for the treatment of irregular shaped bone defects. This study presents the preparation of two different 3D printed scaffolds. 1) PCL-based scaffolds modified with nanohydroxyapatite (HAp) and poly(propylene fumarate) (PPF), and 2) Cell carrying hybrid scaffolds of PCL/GelMA. 3D printed, PCL-based scaffolds were coated with HAp or HAp/PPF before cell seeding and their presence enhanced osteoconductivity and compressive mechanical strength of the scaffold, respectively. Cytotoxicity, irritation and implantation tests showed the biocompatibility of the scaffolds. These scaffolds were implanted into femurs of rabbits either with or without seeding Rabbit Bone Marrow Stem Cells (BMSCs). Bone regeneration was studied with micro CT, and mechanical and histological tests after 4 and 8 weeks of implantation. Tissue regeneration on BMSC seeded PCL/HAp/PPF scaffolds was improved significantly, and after 8 weeks of implantation, compressive and tensile stiffness of femurs (394±25 and 463±10 N/mm) were significantly higher than that of the healthy rabbit femur (316±10 and 392±10 N/mm). The results demonstrate compatibility of the scaffold with bone, and thepotential of the scaffold for use in the production of patient-specific implants for effective bone regeneration. PCL/GelMA hybrid scaffolds were fabricated by printing the polymers side-by-side. The compressive moduli of the scaffolds (102±10 MPa) were comparable with that of human trabecular bone (50–100 MPa). Dental pulp stem cells (DPSCs) were loaded in GelMA and printed between PCL fibers. After printing, 90% of DPSCs were alive and mineralized nodules were observed on day 21 demonstrating osteogenic differentiation.