A) The charge transfer resistance (Rct) of SpyDirect‐ and HDT SAM‐based gates. The impedance measurements were performed with 10 mm [Fe(CN)6]3−/4− in 10 mm PBS, pH 7.4. The Randles circuit model was used to fit the impedance spectra. The biofunctionalized gates were stored in 10 mm PBS, pH 7.4 at 4 °C for 3, 7, and 14 days before use. XPS spectra of C 1s, O 1s, and N 1s of B) SpyDirect‐ and C) HDT SAM‐based gates before and after 7‐day storage in 10 mm PBS, pH 7.4 at 4 °C. D) The response of OECTs gated with SpyDirect‐based electrodes prepared from dried cysteine peptide. The peptide‐modified gates were stored for 7 days in ambient conditions before the nanobody immobilization. All electrode and sensor measurements were done with at least three electrodes.