EFFECTS OF MIXING ON THE COMPOSITION AND MORPHOLOGY OF TISSUE-ENGINEERED CARTILAGE

Cartilage constructs were grown using isolated chondrocytes and biodeg radable polymer scaffolds made of fibrous polyglycolic acid in the for m of 1-cm-dia X 5-mm-thick discs. The scaffolds were seeded in a mixed cell suspension and cultured for up to 8 weeks under static or mired tissue culture conditions in petri dishes and spinner flasks. Turbulen t mixing significantly improved the biochemical compositions and alter ed morphologies of the cartilage constructs, which were the thickest o nes cultured to date in vitro. Constructs from mired cultures were mor e regular in shape and contained up to 70% more cells, 60% more sulfat ed glycosaminoglycan, and 125% more total collagen when compared to co nstructs from static cultures. Mixing also induced the formation of an outer capsule with multiple layers of elongated cells and collagen fi brils around the inner tissue phase, while statically grown constructs consisted of round cells embedded in cartilaginous matrix. Mixing dur ing cell seeding and tissue culture is thus an important parameter for the cultivation of tissue-engineered cartilage in a range of sizes, s hapes and compositions for a variety of clinical applications (e.g, fi brous cartilage for reconstructive surgery or articular cartilage for joint resurfacing).