Synthesis and characterization of electrochemically polymerized indole on screen-printed Ag-conductive transparency...

A flexible, lightweight and low-cost enzymatic bioanode was developed using a screen-printed silver conductive transparency sheet for enzymatic biofuel cell (EBFC) applications. In this work, indole was electrochemically polymerized directly onto the conductive substrate to form a polyindole (PIn) matrix capable of simultaneously entrapping glucose oxidase (GOx) and redox mediator vitamin K₃ (VK₃). The study integrates a disposable transparency-sheet platform with an electroactive PIn network that promotes efficient enzyme immobilization and enhanced electron transfer for glucose bioelectrocatalysis. The synergistic interaction between PIn, VK₃ and GOx significantly improved charge-transfer kinetics and stabilized the bioelectrocatalytic interface, resulting in enhanced electrochemical performance. The fabricated PIn/VK₃/GOx bioanode exhibited a current density of 1.18 mA cm^- 2 in 40 mM glucose solution, demonstrating efficient glucose-dependent electrocatalytic activity. The conductive PIn framework facilitated rapid electron transport between the buried active sites of GOx and the electrode surface, while VK₃ acted as an efficient and biocompatible electron shuttle. The bioanode also displayed good electrical stability, semiconducting behavior, and favorable electrochemical characteristics, highlighting its suitability for flexible and wearable bioelectronic applications.