The use of SU-8 topographically guided microelectrode array in measuring extracellular field potential propagation

The microelectrode array (MEA) can be used to study extracellular field potentials (exFPs) of electrogenic cells. Microcontact printing, which must be repeated after each experiment, is often used to promote accurate positioning of cells onto electrodes. The present study used MEAs with evenly spaced detection electrodes aligning along permanent SU-8 topographical guidance channels to measure propagation direction and speed. Chronotropic agents, isoproterenol (ISO, 1 nM-1 mM), and verapamil (VP, 1 nM-10 μM); and potassium channel openers (KCOs), pinacidil (PIN), and SDZ PCO400 (SDZ), were used to characterize these MEA chips. ISO (1 mM) enhanced the propagation speed from 247.25 ± 50.58 μm/ms 381.29 ± 92.01 μm/ms (n = 9, p < 0.05), whereas VP (10 μM) reduced the propagation speed completely (n = 12, p < 0.001). PIN (1 mM) significantly reduced the propagation speed from 278.6 ± 43.7 μm/ms to 49.7 ± 27.7 μm/ms (n = 10, p < 0.001), whereas SDZ (1 mM) completely stopped the propagation (n = 9, p < 0.001). Both KCOs induced conduction pattern changes similar to those observed in cardiac arrhythmia. The MEA chips with SU-8 guidance channels may be used to study cardiovascular diseases that are related to conduction disruption.