Scaffold-free cartilage by rotational culture for tissue engineering

Our objective was to investigate the hypothesis that tissue-engineered cartilage with promising biochemical, mechanical properties can be formed by loading mechanical stress under existing cell–cell interactions analogous to those that occur in condensation during embryonic development. By loading dedifferentiated chondrocytes with mechanical stress under existing cell–cell interactions, we could first form a scaffold-free cartilage tissue with arbitrary shapes and a large size with promising biological, mechanical properties. The cartilage tissue which constituted of chondrocytes and ECM produced by inoculated dedifferentiated chondrocytes to a high porous simple mold has arbitrary shapes, and did not need any biodegradable scaffold to control the shape. In contrast, scaffold-free cartilage tissue cultured under static conditions could not keep their shapes; it was fragile tissue. The possibility of scaffold-free organ design was suggested because the cartilage tissue increases steadily in size with culture time; indeed, the growth of cartilage tissue starting from an arbitrary shape might be predictable by mathematical expression. For tissue-engineered cartilage formation with arbitrary shapes, biochemical and mechanical properties, loading dedifferentiated chondrocytes with mechanical stress under existing cell–cell interactions has prominent effects. Therefore, our scaffold-free cartilage model loaded mechanical stress based on a simple mold system may be applicable for tissue-engineered cartilage.