Conductive Protein Nanowires Aerobic E. coli Production
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Solution Overview
Problem
The production of electrically conductive protein nanowires is limited by the lack of efficient methods for large-scale production and the high cost of peptide monomers required for in vitro assembly, which restricts their implementation in electronic devices.
Innovation Solution
Genetically modified E. coli cells are used to produce electrically conductive protein nanowires by introducing a polynucleotide encoding a non-native pilin monomer, allowing for aerobic growth and simplified filtration-based harvesting, overcoming the limitations of anaerobic growth and costly synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If in vitro assembly of peptides is used to produce conductive nanofilaments, then conductive protein nanowires can be produced, but the filaments agglomerate into gels at high concentrations and synthesis is expensive
Solution Approach 1:
The patent utilizes the bacterium's own cellular machinery to self-assemble the conductive protein nanowires. The engineered E. coli cells express the pilin monomers and use their native type IV pilus assembly system to automatically polymerize them into conductive nanowires, eliminating the need for external in vitro assembly processes and reducing costs.
Solution Approach 2:
The patent extracts the pilin monomer gene from Geobacter sulfurreducens and transfers it into E. coli, separating the monomer production from the nanowire assembly process. This allows the use of a different, more manufacturable host organism while maintaining the desired nanowire properties.
2Reliability
If Geobacter sulfurreducens is used to produce protein nanowires, then conductive nanowires are obtained, but anaerobic growth conditions are required which complicate large-scale production
Solution Approach 1:
The patent copies only the essential pilin monomer gene from Geobacter sulfurreducens and transfers it into E. coli, rather than using the entire Geobacter system. This allows replication of the nanowire production capability while eliminating the need for complex anaerobic growth conditions required by the native host.
Solution Approach 2:
The patent uses E. coli as an intermediary host organism that can express the Geobacter pilin monomer under simple aerobic conditions. The E. coli type IV pilus assembly machinery serves as the mediator to assemble the heterologous pilin monomers into functional nanowires without requiring the original Geobacter cellular environment.
3Ease of manufacture
If peptide monomers are synthesized for in vitro assembly, then conductive nanowires can be formed, but the cost is high which limits affordability
Solution Approach 1:
The bacterial cells serve as living factories that automatically produce and assemble the nanowires using their metabolic resources. This eliminates the need for expensive external peptide synthesis and purification processes, significantly reducing production costs.
Solution Approach 2:
The patent changes the production parameter from chemical peptide synthesis to biological expression within living cells. This fundamental parameter change exploits the cost-effectiveness of microbial fermentation and natural protein synthesis pathways compared to chemical peptide manufacturing.
Data Source
AI summary
The present invention provides, in various embodiments, genetically modified aerobic bacteria, polynucleotides and methods for expressing and/or harvesting electrically conductive protein nanowires (e-PNs). The present invention also provides e-PNs produced using the genetically modified aerobic bacteria, polynucleotides and methods.