Fig. 8.

Methods for introducing fluid flow to an epithelial submucosal tissue model. With certain complex tissues consisting of an epithelial layer and a stromal compartment there are many possible ways to introduce flow. (A) Flow along the epithelial surface such as that found in the intestinal lumen (B) Flow along the stromal surface partially mimicking blood supply to a tissue (C) Flow across all surfaces of the model (D) Flow perfused through the tissue which can be used to improve the diffusion of nutrients such as oxygen to the centre of thicker tissue constructs. (E) Pulsatile flow, such as that produced by a peristaltic pump, can be used to mimic the pumping motion of the heart for modelling structures such as arteries. (F) Reciprocal oscillatory flow, which changes direction over a set period, allows convective mixing to be introduced using typically very simple apparatus such as a mechanical rocker.