Nutrient transport in biomimetic tissue engineering scaffolds*

To engineer functional tissue, appropriate biomechanical and biochemical cues must be provided to cells to promote growth. Our collaborators have developed a deformable porous hollow fibre membrane scaffold that mimics the mechanical properties of human vasculature. Cells are seeded on the outer surface of these fibres which are then cultured in a bioreactor. Nutrients and growth factors are delivered to the system via flow into the fibre lumen, and they transport to the cells by advection and diffusion through the porous membrane wall.

We develop an axisymmetric fluid-structure interaction model to capture fluid flow and scaffold deformation. We consider steady Stokes flow in and around the membrane which is modelled using linear poroelasticity. We derive a reduced model by exploiting the small aspect ratio of bioreactor radius to length and the large stiffness of the membrane fibre relative to typical fluid pressures. We couple this reduced model to advection-reaction-diffusion equations for nutrient transport and reveal how nutrient delivery to cells depends on membrane permeability. We then determine how spatial variations in scaffold permeability can be established to tune nutrient delivery to the cells.