Influence of Diffusion in Tissue Engineering Bioreactors

Abstract

Flow-through reactor configuration has been studied earlier for developing high aspect ratio tissues. However, flow-through configuration is limited by the range of flow rates that can be used. Hence, split channel parallel flow reactor configurations were evaluated. The objective was to minimize the pressure drop and shear stresses values in the bioreactor which can be used for growing tissues having a diameter of 100 mm. Simulations were performed using COMSOL Multiphysics 3.5a. In the new designs, nutrient mass transport through the scaffold was determined to be diffusion dominated. Hence, the effect of diffusivity changes during tissue regeneration was incorporated into the new designs and changes in nutrient transport were further studied. To reduce the effect of diffusivity changes on nutrient sufficiency throughout the reactor, new flow configurations were considered. These new designs were assessed for regeneration of thick scaffolds. New designs were also compared with previous designs for the possibility of regenerating thick tissues.