On-Chip Amperometric Measurement of Quantal Catecholamine Release Using Transparent Indium Tin Oxide Electrodes

• DOI: 10.1021/ac052037d
• Publication Date: 2006-04-17T04:32:52Z
• Authors: Xiuhua Sun; Kevin D. Gillis
• Keywords: Amperometry; Indium tin oxide

Carbon-fiber amperometry has been extensively used to monitor the time course of catecholamine release from cells as individual secretory granules discharge their contents during process quantal exocytosis, but microfabricated devices offer promise higher throughput. Here we report development a microchip device that uses transparent indium tin oxide (ITO) electrodes measure exocytosis in microfluidic channels. ITO films on glass substrate were patterned 20-μm-wide stripes using photolithography and wet etching then coated with polylysine facilitate cell adherence. Microfluidic channels (100 μm wide by 100 deep) formed molding poly(dimethylsiloxane) (PDMS) photoresist reversibly sealing PDMS slab ITO−glass substrate. Bovine adrenal chromaffin loaded into channel adhered electrodes. Cells stimulated secrete perfusing depolarizing "high-K" solution while monitoring oxidation catecholamines electrode beneath amperometry. Amperometric spikes charges ranging 0.1 1.5 pC recorded signal-to-noise ratio comparable carbon-fiber Further this approach will enable high-throughput measurement simultaneously optical measurements such fluorescence.