Fig. 3
Characterisation of the electrodes and electric field during electrical stimulation (ES). A Voltage measurements over the course of the 2 ES. The colour code indicates the voltage over time. FunGen = 20 Hz frequency provided by the function generator. B Cyclic voltammetry (CV) was performed with a range from − 0.6 V to + 0.9 V. C Cyclic voltammogram within the voltage range of − 0.6 V to + 0.9 V (blue) compared to the extended range from − 1.6 V to + 2 V (red). Note that high currents appear at extended range. D Bode plot of electrochemical impedance spectroscopy (EIS). EIS was performed with input voltages from 10 mVrms to 1 Vrms. Note that, with input voltages of 0.5 and 1 Vrms, the measured impedance (│Z│) changes. E Prediction of voltage flow from impedance measurements with 50 mV (orange), 1 V (green), 1 V and an arbitrary offset to match the data (red) in comparison to measured voltage flow during experiments (blue). Note that the simulation predicted the waveforms well, when EIS data with 1 Vrms input voltage was used. F Time-dependent simulated electric field strength in the centre of the well. G Simulated electric field distribution in the well. Note that the field is homogeneous except in close proximity to the electrodes