Fabrication of two-layer poly(dimethyl siloxane) devices for hydrodynamic cell trapping and exocytosis measurement with integrated indium tin oxide microelectrodes arrays

The design, fabrication and test of a microfluidic cell trapping device to measure single cell exocytosis were reported. Procedures on the patterning of double layer template based on repetitive standard photolithography of AZ photoresist were investigated. The replicated poly(dimethyl siloxane) devices with 2.5 μm deep channels were proved to be efficient for stopping cells. Quantal exocytosis measurement can be achieved by targeting single or small clumps of chromaffin cells on top of the 10 μm × 10 μm indium tin oxide microelectrodes arrays with the developed microdevice. And about 72 % of the trapping sites can be occupied by cells with hydrodynamic trapping method and the recorded amperometric signals are comparable to the results with traditional carbon fiber microelectrodes. The method of manufacturing the microdevices is simple, low-cost and easy to perform. The manufactured device offers a platform for the high throughput detection of quantal catecholamine exocytosis from chromaffin cells with sufficient sensitivity and broad application.