"Microcanals" for modulation of the microfluidic environment of cultured cells

Cell culture perfusion systems are widely used for studying the response of cells to changes in cell culture medium composition or the response of cells to flow. Present perfusion systems consume large volumes of reagents, require manual mixing of reagents prior to introduction into the system inlet, and cannot perfuse different areas of the substrate with dissimilar mixtures. Some of these limitations have been overcome already with perfusion systems based on confining the cells to addressable microchannels. However, cells confined to microchannels suffer from either 1) exposure to shear stress exerted by the flow, or 2) oxygen/nutrient depletion and pH rises in the microenvironment. We have devised a novel, high-throughput perfusion system that will allows us to modulate the fluidic microenvironment of cells based on confining the fluids to microcanals, i.e. microchannels without a roof. Here we demonstrate that fluid flow can indeed be confined by three walls and by a "virtual roof" held by the surface tension of the fluid at the air-fluid interface.