Pgstat 100 n

For the cyclic voltammetry (CV) experiments, a three-electrode glass cell was used with a platinum wire as a working electrode, a platinum wire spiral as a counter electrode, and a silver wire reference using 0.1 M NBu₄PF₆ (TCI Europe) electrolyte solution in dichloromethane (DCM) (Sigma-Aldrich (Poznan, Poland), Chromasolv, HPLC). The potential sweeps were controlled by a MetrohmAutolab PGSTAT 100 N potentiostat. The potential of the silver electrode was determined using a ferrocene redox couple (Fc/Fc⁺) for each measurement set, under the same conditions as the measured samples. The solutions were de-aerated with argon before, and argon kept flowing into the cell, above the solution surface, during measurements. A concentration of 1 mmol/dm³ of the monomers was used for both the measurements and polymerization.

The SPCE was fabricated using a commercial screen printer (ATMA CHAMP Ent. Corp., Taoyuan, Taiwan). A tabletop electrochemical station (PGSTAT100N, Metrohm Autolab, Utrecht, Netherlands) was used for electropolymerization of PANI and electrodeposition of AuNCs. The same electrochemical station was used to perform EIS measurements for each step during electrode modification and after immunosensing. The surface morphology of the SPCE before and after surface modification with PANI/AuNCs nanocomposite film was characterized using a field emission scanning electron microscope (Hitachi SU-8010, Tokyo, Japan) operated at an accelerating voltage of 15 kV.