Cross-linked glucose oxidase clusters for biofuel cell anode catalysts

Area of Science:

• Biotechnology
• Electrochemistry
• Materials Science

Background:

• Efficient enzyme immobilization on conductive scaffolds is crucial for developing enzyme-based biofuel cells.
• Direct electron transfer from enzyme active sites to scaffolds is key for bioanode performance.

Purpose of the Study:

• To create and evaluate cross-linked enzyme clusters (CECs) of glucose oxidase (GOx) immobilized on functionalized carbon nanotubes (CNTs).
• To assess the potential of CEC-CNTs for developing GOx-based bioanodes utilizing direct electron transfer.
• To optimize GOx:CNT ratios for enhanced enzymatic activity and bioanode performance.

Main Methods:

• Generation of CEC-CNTs using various weight-to-weight ratios of GOx to CNT.
• Enzymatic activity assays comparing CEC-CNTs to free GOx.
• Scanning transmission electron microscopy (STEM) for visualizing CEC cluster size and localization.
• Electrochemical analysis to confirm direct electron transfer and measure biofuel cell performance.

Main Results:

• CEC-CNTs generated from a 100% GOx solution exhibited the highest enzymatic activity.
• STEM analysis showed localized CEC clusters of approximately 78 µm² on the CNT surface.
• Electrochemical tests confirmed direct electron transfer between GOx and the CNT scaffold.
• Biofuel cells utilizing GOx CEC-CNT bioanodes achieved a peak power density of approximately 180 µW cm⁻².

Conclusions:

• Nano-to-micro-sized active enzyme clusters are a promising strategy for designing enzyme-specific biofuel cells.
• CEC-CNTs offer an effective platform for enhancing enzyme activity and direct electron transfer in bioanodes.
• This approach supports the development of powered implantable devices using enzyme-based biofuel cells.