Microelectrode Array Designing for Dummies: Contribution of the Tracks to the Impedance Behavior and the Noise Level

Whether it is about harnessing living cells as sensing elements or just basic cell research, microelectrode arrays (MEAs) can be used for recording electrical response of various cell types in vitro, especially cardiac and neuronal cells. Even if commercial MEAs with standard layouts are easily available, several research groups end up fabricating or at least designing their own MEAs to meet better the needs of their specific research questions. In theory, the resistance of the tracks that connect the electrodes to the contact pads is several orders of magnitude smaller than the total electrode impedance, and thus there should be plenty of room to play with the track dimensions and conductivity. Still, relatively large track widths, thicknesses and highly conductive (= expensive) track materials are usually favored - "just in case". In this study, we tested several track widths, thicknesses and materials. The results confirmed that playing too safe with the tracks has been unnecessary and, on the other hand, one cannot gain any benefit by exaggerating the track dimensions or conductivity. On the contrary, by reducing the track dimensions and choosing less conductive materials one could e.g., get better visibility and cost savings as well as improve the adhesion of microfluidic add-ons.