Model to design multilayer tissue engineering scaffolds

In tissue engineering scaffolds, nutrient transport to cells is a major hurdle for building viable 3D tissue scaffolds. In vivo, a complex network of blood vessels and capillaries delivers nutrients and oxygen to the tissue. For in vitro build constructs the distance to the main nutrient source is often long resulting in nutrient gradients over the scaffold and decreased cell proliferation or even cell death in parts of the scaffold. This work describes a numerical model for designing a multilayer scaffold for tissue engineering by stacking sheets featuring microchannels. These sheets fabricated by phase separation micromolding (PSμM) allow nutrient perfusion through the 3 ^D scaffold whereas inner-porosity of the sheets guarantees diffusion between layers. The model predicts significant nutrient limitation occurs under static conditions for scaffolds having over 3 sheets. The situation can improve dramatically under dynamic conditions when perfusion occurs through the microchannels.