Stem cell research has the potential to produce novel treatments for previously incurable diseases and injuries. The application of controlled shear flow to undifferentiated embryonic stem cells promotes enhanced expansion of cell lines (Fok, E. and Zandstra, P., 2005). Shear stress provides a stimulus for differentia- tion, particularly for cell types that naturally respond to physiological shear such as endothelial cells (Yamamoto et al 2003; Illi et al 2005;Wang et al 2005;Yamamoto et al 2005). Differentiation of cells into specific cell types and subsequent production of biomaterials is also facilitated by mechanical shear force. One example of this would be chondrocytes used to produce cartilage (Shuman et al 2006).