A novel hybrid platform for the preparation of disposable enzyme biosensors based on poly(3,4-ethylenedioxythiophene) electrodeposition in an ionic liquid medium onto gold nanoparticles-modified screen-printed electrodes

A novel electrochemical platform for the preparation of disposable enzyme biosensors is reported in this work. This platform is constructed by electrodeposition of poly(3,4-ethylenedioxythiophene) (PEDOT) using the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) as the electropolymerization solvent onto gold nanoparticles-modified screen-printed carbon electrodes (SPCE). The enzymes alcohol dehydrogenase (ADH) or Tyrosinase were entrapped onto the electrode surface during the electropolymerization step. The potentiostatic electropolymerization process of PEDOT on gold nanoparticles-modified SPCE was optimized and the resulting modified electrodes characterized voltammetrically and by electrochemical impedance spectroscopy (EIS). The NADH amperometric detection at PEDOT/nAu/SPCE was also optimized and compared with that produced at a PEDOT/SPCE. ADH/PEDOT/nAu/SPCEs were constructed. The measured current for ethanol was 30% larger than that obtained using ADH/PEDOT/SPCEs. At a detection potential of +300 mV, a calibration graph for ethanol with a linear range between 5 and 100 μM was obtained with a detection limit of 2 μM. The PEDOT/nAu/SPCEs electrodes were also tested for the preparation of Tyrosinase biosensors. Using a detection potential of −150 mV, a linear calibration graph for phenol was constructed over the 0.1–50 μM concentration range, with a limit of detection of 0.02 μM.