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 x 10(6)) into cylindrical chambers (11.04.5 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 mmx2 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. (C) 2003 Published by Elsevier Science Ltd on behalf of OsteoArthritis Research Society International.