A static, closed and scaffold-free bioreactor system that permits chondrogenesis in vitro

Objective: To characterise in vitro engineered cartilaginous constructs made employing a novel static, scaffold-free and closed chamber system. Design: Chondrocytes derived from slaughter age pigs (3–6 months) were seeded at high density (20×10 6) into cylindrical chambers (1.0×0.5 cm) and were maintained between an upper and a lower membrane (100 kDa) for 21 days and subsequently cultured in open culture for 7 additional days. Results: Viable constructs produced were approximately 10 mm×2 mm in size and were stable enough to be handled by surgical pincers. Histology and electron microscopy evaluations revealed a neo-cartilage structure of high cell density with a comprehensive extracellular matrix. Predominately collagen type II and negligible amounts of collagen types I and X were detected using RT-PCR and SDS-PAGE analyses. Conclusions: In this study, we provide evidence of a scaffold-free system that can produce immature hyaline-like cartilaginous constructs suitable for in vivo implantation, or that may be useful for in vitro studies of events related to the process of chondrogenesis.