Design and Fabrication of Multi-Component Scaffolds for Bone Tissue Engineering, 01-R8078
Inclusive Dates: 07/07/09 01/07/11
Background — The ideal bone scaffold should have a modulus match to that of bone, while also biodegradable, tough, cheap, easily processable and biocompatible. Moreover, the scaffold itself should be able to stimulate bone-like tissue growth and accommodate intrinsic or external osteo-inductive factors. In light of these requirements and challenges to repair and regenerate bone defect, this research project aims to develop Mg alloy-based scaffolds to stimulate bone growth.
Approach — To develop an ideal bone scaffold, SwRI researchers have developed a three-dimensionally coated, cylindrical, wrapped Mg alloy scaffold with interlayer spaces and lumen (Fig. 1a); in-vitro biocompatiblity testing methods using mesenchymal stem cells (MSCs, Fig. 1b) and in-vitro corrosion testing (electrochemical corrosion, mass, pH, etc.); and in-vivo testing methods using both rat and rabbit models. X-ray radiographs and micro-CT imaging, blood CPK measurement, SEM/EDX analysis and biomechanical testing have been used to characterize the implantation outcome.
Accomplishments — Without any external osteoinductive factors (BMP2, thrombin peptide TP508, gene transfer of BMP-6, platelet-rich plasma, stem cells and anabolic drugs), SwRI's Mg alloy scaffolds resulted in partial-to-full regeneration of rabbit critical-size ulna defects within 12 weeks. The statistical analysis showed that, on average, the intact ulnae and the implant-treated ulnae exhibited a similar biomechanical performance in one group. Radiograph (Fig. 1c-d), SEM/EDX and Micro-CT analysis (Fig. 1e) indicated that bone-like tissue grows inside and outside the scaffold. This study suggests the SwRI-designed and fabricated Mg alloy scaffold is promising for bone regeneration.