A Novel Through-Thickness Perfusion Bioreactor for the Generation of Scaffold-Free Tissue Engineered Cartilage

The objective of this study was to characterize our designed through-thickness perfusion bioreactor which could generate large scaffold-free tissue engineered cartilage constructs. The hypothesis being that through-thickness perfusion could accelerate maturation of scaffold-free tissue engineered cartilage, grown in transwell culture inserts large enough to repair typical size chondral lesions in the human knee. Internal cell culture media temperature and pH were examined over time, upon implementation of the bioreactor perfusion system inside a CO2 incubator, to ensure adequate regulation conducive to cell viability. Results indicate that temperature and pH both equilibrate within approximately 3 h. The bioreactor was tested for its efficacy to support formation of 4.5 cm2 constructs by porcine neonatal chondrocytes. Tests were conducted under three conditions: immediate perfusion with flow from bottom to top, immediate perfusion with media flow from top to bottom, and bottom to top perfusion after four weeks of static culture, giving the cells time to self-aggregate into a consolidated construct prior to perfusion. The best cell culture results were obtained when perfusion was delayed for four weeks relative to the immediate perfusion of the other methods, and this should be further investigated.