(Dr. Paul Neitzel, advisor)
"Characterization of Flow within a Polymer Scaffold in a Compression-Perfusion Bioreactor"
This thesis addresses an experimental study of the flow environment within the tissue construct of a compression-perfusion bioreactor developed for the growth of articular cartilage. A model bioreactor was designed and built to faithfully reproduce the fluid dynamics within the prototype, as determined by the requirements for dynamic similarity. Refractive-index matching was employed to allow visualization of flow without distortion within the felt, and more particularly in the immediate vicinity of the fibers. A Particle Image Velocimetry (PIV) method was improved and used to quantify the velocity and shear-stress fields induced by perfusion and combined application of perfusion and dynamic compression. The comparison of the scaled results suggests that simultaneous perfusion rate of 82 mL/min and dynamic compression (5% strain; static offset of 10%; 0.5 Hz frequency) give an average of the maximum wall-shear stress value at 9.46 N/m2 that is higher than the one found when only perfusion is applied (i.e. 6.78 N/m2). When compared with the prototype, this would imply that a maximum wall-shear stress at 0.36 N/m2 gives better cartilage growth conditions than a one at 0.20 N/m2.