Figure 7.

Effect of corroded insulation on signal amplitude. (a) Neuronal network in BPH medium on a BMT MEA well with a badly corroded insulation layer after 21 days in adherent culture and corresponding spike waveforms from day 22 recordings from two representative electrodes (2 and 5). (b) Neuronal network in NDM medium at 17 days in adherent culture and recorded waveforms (6 and 9) from day 20 on a BMT MEA still with a proper insulation layer. The boxes are ±50 μV and 3 ms. (c) Example of insulator layer corrosion in BMT MEA after 3 weeks of cell culture in BPH medium. The green arrows indicate examples of fully corroded areas, demonstrating that most of the tracks have lost their insulation. (d) Example of insulator layer corrosion in BMT MEA after 3 weeks of cell culture in NDM medium. The insulator layer may have thinned all around, but it is fully corroded only from a small, barely visible area near the electrode as indicated by the red arrow.