FIG. 3.

Cyclic voltammograms recorded in a PBS phosphate buffer solution (10 mM and pH = 7.4) with a scan rate of 50 mV/s during steps 1 and 2 (a) for a macroelectrode and (b) inside the chip; Nyquist plots obtained in the frequency range from 10 kHz to 0.5 Hz by applying 10 mV (AC mode) in 10 mM [Fe(CN)₆]^3−/4−: (c) for the macroelectrode at the fixed potential 0.25 V vs. Ag/AgCl and (d) for the electrode integrated in the fluidic channel at 0.25 V vs. Fc/Fc⁺. The symbols are the experimental data and the solid lines are the fitted curves using the equivalent circuit showed in inset. EIS data have been satisfactorily fitted by the equivalent circuits that are reported in supplementary material SI.3.⁴³