Palladium nanoparticles (Pd-NPs) have been approved as an effective catalyst for hydrogen peroxide
decomposition which is released during specific enzymatic reactions. However, the general operational
principles and electrochemical performance of Pd-NPs-based nanobiosensors have been poorly
exploited. Here, the electrochemical behavior of oxidase-associated peroxide oxidation co-catalysis of
the modelled microanalytical system based on screen-printed electrodes modified by electroplated PdNPs as an electrocatalyst, glucose oxidase (GOx) or alcohol oxidase (AOx) as a bioreceptor and the
ionomer Nafion as a polymeric binding agent was studied in detail. The impact of palladium surface
oxides and adsorbed oxygen on the activity and product selectivity in an oxidase type of nanobiosensor
was ascertained. To avoid PdO and oxygen electroreduction affecting the entire amperometric response
of Pd-NPs-based nanobiosensors, a special two-step polarization procedure was proposed. Under the
established electrochemical conditions, Pd-NPs-based nanobiosensors with encapsulated oxidases
showed a wide dynamic range towards selective bioanalyte detection, excellent basic line stability, accuracy and resistance to the presence of interfering electrochemical species. This work can serve as a
guideline for the search and validation of operational principles of novel biosensors based on
nanoparticles
