Figure 1.

Constant perfusion of oxygen and nitrogen compressed gasses into microchannels separated by a diffusion gap exposes cells to a spatial linear oxygen gradient. (A) A schematic cross-sectional view of the microchannel device demonstrates diffusion from an oxygen channel and a nitrogen channel across a thin PDMS membrane establishes an oxygen gradient to which cells cultured on the membrane are exposed. (B) The experimental setup schematic for gas perfusion shows flow from a compressed gas tank to a glass tube rotometer and then through a mini gas regulator and into a microchannel of the device. The connection of a manometer by a three-way valve is used to monitor that pressure remains equal within each microchannel.