Fig. 6: Electrochemical impedimetric characterization of the simplified fabrication of the antibody-conjugated IDE.
a Compilation of all impedimetric recordings from the various states of the IDE. b Impedance data from a, including fitted models for each state, derived from the equivalent circuit shown in the inset. The “Plain” IDE state was fitted utilizing the equivalent circuit shown in Fig. 4b, as the fabrication of the sensor up to this point is identical. c Enhanced data from b, showing the 1–4 MHz region of interest, where changes in the faradaic reactions at the electrode surface are apparent. Here, as opposed to that shown by the temperature sensor, a clear increasing impedance trend is observed. d Nyquist plot variation of the data from b and c plotted as the imaginary impedance against the real impedance. The curve shown corresponds to the first faradaic reactions governed by the initiation of the equivalent circuit, present at the higher frequencies indicated. The curve here is governed by R1**, R2**, and CPE1** and confirms the increase in real impedance shown in c. Additionally, a change in the curve shape is observed, owing to the capacitive elements imposed on the IDE surface from antibody conjugation and analyte binding
