PEDOT:PSS – A suitable interface for the enzyme PQQ-GDH on electrodes

-value of 0.16 ± 0.03 mM. The catalytic signal can be tuned by adjusting polymer thickness and enzyme loading, while remaining stable across a pH range of 5.5 to 7.2. A less commonly used, but powerful method - faradaic impedance spectroscopy (f-EIS) - was successfully employed to monitor the enzymatic activity on the polymer layer. These findings support mediator-free bioelectrocatalysis and are consistent with direct electron transfer (DET) of the enzyme at the polymer-modified electrode. Our work opens new possibilities for biosensing applications, including flexible and stretchable field-effect transistor (FET) electronics where PEDOT:PSS is widely used.