Une surprenante découverte de nanofils bactériens pourrait conduire à des circuits électriques vivants et auto-réparateurs

Bactéries produisant des nanofils de cytochrome OmcS

Bactéries produisant des nanofils constitués de cytochrome OmcS. Crédit : Ella Maru Studio

Le refroidissement accélère les électrons dans les nanofils bactériens

Le sol sous nos pieds et sous le plancher océanique est un réseau électriquement chargé créé par des bactéries qui “expirent” des électrons en excès à travers de minuscules nanofils dans un environnement pauvre en oxygène. En identifiant le mécanisme de circulation des électrons, Yale University researchers have been studying ways to improve this natural electrical conductivity within nanowires 1/100,000th the width of a human hair.

In a new study published today (May 11, 2022) in Science Advances, a team led by graduate student Peter Dahl with Nikhil Malvankar, Assistant Professor of Molecular Biophysics and Biochemistry in the Microbial Sciences Institute, and Victor Batista, Professor of Chemistry, found that nanowires move 10 billion electrons per second without any energy loss. This research explains the remarkable capacity of these bacteria to send electrons over long distances.

The researchers also found that cooling the environment around the nanowires of the bacteria Geobacter from room temperature to freezing increases conductivity 300-fold. This is very surprising because cooling typically freezes electrons and slows them down in organic materials. By combining experiments with theory, the researchers found that colder temperatures restructure hydrogen bonds and flatten heme proteins within nanowires, thus enhancing the flow of electricity.

Leveraging this naturally occurring electrical grid might one day lead to the development of living and self-repairing electrical circuits, new sources of electricity, and bioremediation strategies.  

Reference: “300-fold conductivity increase in microbial cytochrome nanowires due to temperature-induced restructuring of hydrogen bonding networks” 11 May 2022, Science Advances.
DOI: 10.1126/sciadv.abm7193

Other authors include Sophia Yi, Yangqi Gu, Catharine Shipps, Jens Neu, Patrick O’Brien, Dennis Vu and Sibel Ebru Yalcin from the Malvankar Lab, and Atanu Acharya, Uriel Morzan, and Subhajyoti Chaudhuri from the Batista Lab.

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