Open environment micro device for integration of patch clamp instrumentation with targeted microfluidic chemical delivery

We describe a technique for the fabrication and use of a microfluidic flow device that has portions that are open to the external environment. Matching inlet and outlet flow rates in the device forms virtual walls through surface tension at the liquid-air interface. Traditional instrumentation, such as the patch-clamp pipette, can be introduced into the flow stream through the surface-tension walls, thereby combining decades of electrophysiology techniques with the benefits of microfluidic environmental control of in-vitro tissue samples such as neural cultures and brain slices.