Generating oxygen gradients across the tissue cultures
resembles the in vivo conditions more than that across single
layer cell cultures. Most of the devices are dependent on the
same gas infusion methods [9, 10]. However, their
operation requires fluid flow velocities higher than those
found in normal interstitium. This inevitably deranges
physiologic concentration gradients of cell signals and other
chemicals, and induces shear stress on the cells. The
resultant release of inflammatory markers and changes in
cellular metabolism skew the data [