(Dr. Paul Neitzel, advisor)

"Flow Characterization and Tissue Growth Modeling of Cartilage Growth in Bioreactors"

Abstract

Bioreactors are devices used for the growth of tissues in a laboratory environment. They exist in many different forms, each designed to enable the production of high-quality tissues. The dynamic environment within bioreactors is known to significantly affect the growth and development of the tissue. Chondrocytes, the building blocks of articular cartilage, for example, are stimulated by mechanical stresses such as shear, as compared with those in tissues grown under static incubation conditions. On the other hand, high shear can damage cells. Consequently the shear-stress level has to be controlled in order to optimize the design and the operating conditions of bioreactors.

Spinner flasks and rotating-wall vessels (RWV) have been used for the production of articular cartilage in vitro. The present research focuses on the characterization of the flow field within these bioreactors, with respect to their use for the production of articular cartilage. Experimental measurements of the flow field will be carried out in a model bioreactor using particle-image velocimetry (PIV). The experimental results will be compared with numerical simulations performed with the commercial CFD package FLUENT. Finally, the fluid-dynamic models will be used to develop a tissue-growth model for use in aiding the optimization of existing devices, and in the design of new ones.