title: Lithographic Microfabrication of a 16-Electrode Array on a Probe Tip for High Spatial Resolution Electrochemical Localization of Exocytosis.
abstract: We report the lithographic microfabrication of a movable thin film microelectrode array (MEA) probe consisting of 16 platinum band electrodes placed on top of a supporting borosilicate glass substrate. These 1.2 μm wide electrodes were tightly packed and positioned parallel in two opposite rows within a 20 μm × 25 μm square area and with a distance less than 10 μm from the edge of the glass substrate. We demonstrate the ability to control and place the probe in close proximity to the surface of adherent bovine chromaffin cells and to amperometrically record single exocytosis release events with high spatiotemporal resolution. The two-dimensional position of single exocytotic events occurring in the center gap area separating the two rows of MEA band electrodes and that were codetected by electrodes in both rows was determined by analysis of the fractional detection of catecholamine released between electrodes and exploiting random walk simulations. Hence, two-dimensional electrochemical imaging recording of exocytosis release between the electrodes within this area was achieved. Similarly, by modeling the current spikes codetected by parallel adjacent band electrodes positioned in the same electrode row, a one-dimensional imaging of exocytosis with submicrometer resolution was accomplished within the area. The one- and two-dimensional electrochemical imaging using the MEA probe allowed for high spatial resolution of exocytosis activity and revealed heterogeneous release of catecholamine at the chromaffin cell surface.
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden.
authors.forename: Joakim
authors.initials: J
authors.lastname: Wigström
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Dunevall
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden.
authors.forename: Neda
authors.initials: N
authors.lastname: Najafinobar
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden.
authors.forename: Jelena
authors.initials: J
authors.lastname: Lovrić
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Ewing
authors.affiliation: Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden.
authors.forename: Ann-Sofie
authors.initials: AS
authors.lastname: Cans
mesh_terms: D000818:Animals; D002244:Carbon / Q000737:chemistry; D000077482:Carbon Fiber; D002417:Cattle; D019439:Chromaffin Cells / Q000166:cytology / Q000378:metabolism; D055664:Electrochemical Techniques; D004566:Electrodes; D005089:Exocytosis / Q000502:physiology*; D055616:Microtechnology; D010984:Platinum / Q000737:chemistry
chemical_list: D000077482:Carbon Fiber; D010984:Platinum; D002244:Carbon