(516au) Simulation and Validation of Nutrient Transport Models in Tissue Engineering Scaffolds

Mass transfer is an important aspect of tissue engineering that is often overlooked when designing scaffold materials. Nutrient mass transfer limitations lead to a host of problems during tissue regeneration. The issue is complicated further when using composite materials reinforced with impermeable membranes. One such composite has been developed to mimic the mechanical properties of small intestinal submucosa, a natural material clinically used in regeneration. The composite is a sandwich configuration with porous natural polymers surrounding a synthetic polymer membrane [1]. The synthetic membrane creates a transport barrier within the scaffold.

In this study, mass transport of nutrients (oxygen as a marker) within 2 mm thick porous scaffolds was simulated using the computational fluid dynamics package CFX (ANSYS Inc, Canonsburg, PA.). Parallel plate reactor assembly with a length of 8 cm and a width of 2.5 cm which are spaced 2 mm apart was drawn with three different entrance and exit designs.

Simulation results were experimentally validated using a parallel plate reactor of dimension described above. Oxygen distribution within the bioreactor can be effectively measured by using a ruthenium-coated glass slide as the ruthenium fluorescence is deactivated in the presence of oxygen, thereby allowing the correlation of the amount of oxygen present in the flow system. The reactor is set on an optics system utilizing a digital camera to visualize fluid flow. Flow profiles and residence time distributions in the reactor are calculated using the camera output and concentration data at the reactor outlet. These results provide new insights into designing composite scaffolds with minimal transport limitations.

Reference:

[1]. Lawrence B, Maase E, Lin H, Madihally S. Multilayer Composite Scaffolds With Properties Similar To Small Intestinal Submucosa. Biomaterials (submitted) 2007..