Biosynthetic Electronic Interfaces for Bridging Microbial and Inorganic Electron Transport

Area of Science:

• Bioelectronics
• Materials Science
• Microbiology

Background:

• Electron transport in biological and inorganic systems presents a fundamental challenge for bioelectronic device development due to mismatches in structure and thermodynamics.
• Effective coupling at the biotic/abiotic interface is crucial for advancing bioelectronic devices for engineering applications.

Purpose of the Study:

• To develop a bottom-up, biosynthetic approach to enhance electron transport and coupling at the biotic/abiotic interface.
• To investigate the use of graphene oxide as a respiratory electron acceptor for electrochemically active bacteria.

Main Methods:

• Utilized electrochemically active bacteria, specifically *G. sulfurreducens*, as a model system.
• Employed graphene oxide as a direct respiratory electron acceptor, facilitating extracellular electron transfer.
• Analyzed the biofilm/electrode interface using cyclic voltammetry to assess electron transfer kinetics.

Main Results:

• Achieved direct reduction of graphene oxide by *G. sulfurreducens*, closely coupled with outer membrane cytochromes.
• Reduced contact resistance at the biofilm/electrode interface by 90%.
• Transformed electron transfer from a low-current, rate-limited profile to a high-current, diffusion-limited profile, indicating minimized charge transfer barriers.

Conclusions:

• The integration of reduced graphene oxide (rGO) effectively minimizes charge transfer barriers at the biofilm/electrode interface.
• This strategy enables seamless integration of biological and artificial electronics, offering insights into biological electron transport.
• Opens new opportunities for applications in biosensing, biocomputing, and bioenergy conversion.