Concentric Cylinder Bioreactor for Production of Tissue Engineered Cartilage:Effect of Seeding Density and Hydrodynamic Loading on construct development

摘要

A concentric cylinder bioreactor has been developed to culture tissue engineered cartilage constructs under hydrodynamic loading.This bioreactor operates in a low shear stress environment has a large growth area for construct production allows fro dynamic seeding of constructs,and provides for a uniform loading environment.Porous poly-lactic acid constructs,seeded dynamically in the bioreactor usign isolated bovine chondroxytes,were cultured for 4 weeks at three sedding densities (60,80 100 x 10~6 cells per bioreactor) and three different shear stresses (imposed at 19,38,and 76 rpm) to characterize the effect of chondrocyte density and hydrodynamic loading on construct growth.Construct seeding efficiency with chongrocytes is greater than 95% within 24 h Extensive chondrocyte proliferation and matrix deposition are achived so that after 28 days in culture constructs from bioreactors seeded at the highest cell densities contain up to 15 X 10~6 cells 2 mg GAG and 3.5 mg collagen per construct and exhibit morphology mimilar to that fo native carttilage.In cultures under different staedy hydrodynamic dlading the date demonstrate that higher shear stress suppresses matriz GAG deposition and encourages collagen incorporation In contrast under dynamic hydrodynamic loading conditions,cartilage constructs exshibit robust matrix collagen and GAG deposition.The date demonstrate that the concentric cylinder bioreactor providws a favorable dydrodynamic environment for cartilage construct growth and differentiation Notably construct matrix accumulation can be manipulated by hydrodynamic loading.This bioreactor is useful for fundamental studies of construct prowth and to assess the significance of cell density nutrients and hydrodynamic loading on cartialge development.In addition studies of cartilge sissue engineering in the well-characterized uniform envirpoment of the concentric cylinder bioreactor will develop important knowledge of bioprocessing parameters critical for Large-scale production of engineered sissues.