It was shown that the sensitivity and detection limit of the developed Pt-based biosensors depend on the amount of PPO and Fc incorporated into the PPY membrane, and also on their ratio. The modification of the biosensor by a Nafion membrane offered three benefits: an increase in sensitivity, an improvement in detection limit, and a significant minimization of the AA interference. An optimum biosensor architecture was made by polymerizing PPY for 40 minutes from a pyrrole solution containing 2,400 U mL-1 of PPO and 10 mM of Fc, on top of which a thin Nafion film was formed. Using chronoamperometry as a detection technique, this biosensor yielded a DA detection limit of 20 nM, which makes it suitable for monitoring DA levels in brain. Even a lower detection limit, 10 nM, and higher sensitivity were achieved by using electrochemical impedance spectroscopy (EIS) as a detection technique. Unfortunately, the developed biosensor lacked operational stability, predominately due to the leakage of PPO and Fc into the storage solution.