Scientists Discover Bacteria Growing Microscopic “Electrical Wires” With Extraordinary Conductivity

Scientists have discovered that certain bacteria can conduct electricity over long distances, with conductivity levels comparable to electronic inks. The bacteria, known as cable bacteria, have been found to have a network of nickel-rich nanoribbons arranged as a natural electrical cable. The structure is unlike conventional biological electron transfer systems and may represent the first known example of a metal-organic framework produced by a living organism. The study found that each conductive fiber contains roughly 11 thin nanoribbons, about 1.4 nanometers wide, made from nickel bis-dithiolene complexes. The nanoribbons are arranged in an extended, highly ordered electrical pathway, allowing charge to spread across overlapping molecular networks. The discovery could lead to the development of flexible, biodegradable electronics that organisms can manufacture themselves.

• The study was published in Nature Communications.
• The research team used electron microscopy, X-ray fluorescence, Raman spectroscopy, and computer modeling to analyze the structure.
• The conductivity of the nanoribbons was measured up to 15,000 siemens per centimeter, which is among the highest reported for any metal-organic structure.
• The findings could provide a biological blueprint for creating flexible, biodegradable electronics.

The discovery of cable bacteria's electrical conductivity challenges existing models of electron transfer in biology. Previous research suggested that electron conduction in bacteria relied on proteins containing iron-containing cofactors, but cable bacteria use sulfur-bound nickel rather than iron. The new structural work may help explain how the bacteria achieve such high conductivity. The arrangement of the nanoribbons creates extensive electronic interaction and delocalization, allowing charge to spread across overlapping molecular networks. The structure also offers mechanical advantages, such as strength and flexibility, which may help the bacteria navigate through sediment while maintaining electrical contact between cells. The discovery could broaden scientists' understanding of what biology can manufacture, as metal-organic frameworks are typically designed by chemists, not living organisms. The study suggests that nature may have found a way to overcome the trade-off between electrical performance and mechanical robustness.

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