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Purpose-The purpose of this work was to investigate the effects of triisocyanate composition on the biological and mechanical properties of biodegradable, injectable polyurethane scaffolds for bone and soft tissue engineering.Methods-Scaffolds were synthesized using reactive liquid molding techniques, and were characterized in vivo in a rat subcutaneous model. Porosity, dynamic mechanical properties, degradation rate, and release of growth factors were also measured.Results-Polyurethane scaffolds were elastomers with tunable damping properties and degradation rates, and they supported cellular infiltration and generation of new tissue. The scaffolds showed a two-stage release profile of platelet-derived growth factor, characterized by a 75% burst release within the first 24 h and slower release thereafter.Conclusions-Biodegradable polyurethanes synthesized from triisocyanates exhibited tunable and superior mechanical properties compared to materials synthesized from lysine diisocyanates. Due to their injectability, biocompatibility, tunable degradation, and potential for release of growth factors, these materials are potentially promising therapies for tissue engineering.

Articular cartilage has a limited capacity for self-renewal. This article reports the development of a porous hydroxyapatite/ collagen (HAp/Col) scaffold as a bone void filler and a vehicle for drug administration. The scaffold consists of HAp nanocrystals and type I atelocollagen. The purpose of this study was to investigate the efficacy of porous HAp/Col impregnated with FGF-2 to repair large osteochondral defects in a rabbit model. Ninety-six cylindrical osteochondral defects 5 mm in diameter and 5 mm in depth were created in the femoral trochlear groove of the right knee. Animals were assigned to one of four treatment groups: porous HAp/Col impregnated with 50 ml of FGF-2 at a concentration of 10 or 100 mg/ml (FGF10 or FGF100 group); porous HAp/Col with 50 ml of PBS (HAp/Col group); and no implantation (defect group). The defect areas were examined grossly and histologically. Subchondral bone regeneration was quantified 3, 6, 12, and 24 weeks after surgery. Abundant bone formation was observed in the HAp/Col implanted groups as compared to the defect group. The FGF10 group displayed not only the most abundant bone regeneration but also the most satisfactory cartilage regeneration, with cartilage presenting a hyaline-like appearance. These findings suggest that porous HAp/Col with FGF-2 augments the cartilage repair process. ß

These results suggest that global 2D strain might provide useful information on myocardial fibrosis and cardiac events in HCM patients with normal chamber function.

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