In vitro tissue engineering to generate a human-sized auricle and nasal tip

Objectives/Hypothesis: Tissue engineering has successfully generated cartilage in a xenograft and an autograft model. However, challenges remain with both of these in vivo techniques before clinical application can be realized. We hypothesized that a human-sized cartilaginous structure could be generated completely in vitro as a complementary or an alternative technique. Methods: Scaffolds were created in the shape of five fall-sized human auricles and five nasal tip cartilaginous skeletons. Bovine shoulder chondrocytes at a concentration of 50 million cells/mL were seeded onto the scaffolds and were grown for 12 weeks in vitro. Two of the auricular scaffolds had internal support provided by soft acrylic sheets and were later implanted into nude rats. Results: All of the scaffolds maintained shape and size through 12 weeks of in vitro culture. On gross examination the scaffolds were progressively replaced by cartilage, which was confirmed by histological and biochemical analysis. The auricular scaffolds with the acrylic internal support had the most natural rigidity, which was observed by gentle palpation. The nasal scaffolds maintained excellent definition even without internal support. Conclusion: An adult human-sized auricle and nasal tip cartilaginous structure can be grown entirely in vitro using principles of tissue engineering.