Tuning Structural Changes in Glucose Oxidase for Enzyme Fuel Cell Applications

Area of Science:

• Bioelectronics
• Enzyme immobilization
• Electrocatalysis

Background:

• Stabilization and electrical contacting of redox enzymes are crucial for bioelectronic devices like biosensors and enzyme fuel cells (EFCs).
• Achieving long-term enzyme stability and efficient electron transfer to electrodes remains a challenge in device development.

Purpose of the Study:

• To investigate the stabilization of glucose oxidase (GOx) using Nafion immobilization.
• To evaluate the impact of Nafion on GOx conformation, activity, and stability.
• To assess the performance of a Nafion-immobilized GOx system in a prototype enzyme fuel cell (EFC).

Main Methods:

• Immobilization of glucose oxidase (GOx) using Nafion.
• Characterization of GOx conformation and activity post-immobilization.
• Assembly of a prototype EFC using a GOx/Nafion system interfaced with a carbon cloth electrode.
• Performance evaluation of the EFC through polarization and power density measurements.

Main Results:

• Nafion immobilization significantly increased GOx stability, maintaining activity for over 120 days.
• The immobilization process altered GOx conformation but did not compromise its catalytic activity.
• The GOx/Nafion system successfully generated power in a prototype EFC, demonstrating Nafion-assisted electron transfer.
• Enzyme structure and active site behavior were influenced by pH-dependent conformational equilibrium.

Conclusions:

• Nafion is an effective material for stabilizing glucose oxidase, leading to durable and high-performing enzyme fuel cells.
• The protective effect of Nafion can be tuned by adjusting parameters like pH, allowing for optimization of EFCs.
• This study provides a pathway for fabricating robust bioelectronic devices with enhanced electrocatalytic properties.