Microfluidic chamber with active suction ports for localized chemical stimulation of brain slices

We report a novel microfluidic chamber with active suction ports to locally deliver soluble neuromodulators into a brain slice in a precisely controlled manner. A two-level soft-lithography process is developed to fabricate injection/suction port assemblies integrated with microchannels. Fluorescence imaging is used to characterize the flows around an injection port while switching the suction port on and off. To demonstrate biological applicability of the chamber, we use a focal delivery of potassium chloride solution to induce cortical spreading depression (CSD) in mice brain slices.