Abstract
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.