An Ordered and Fail‐Safe Electrical Network in Cable Bacteria

Cable bacteria are an emerging class of electroactive organisms that sustain unprecedented long‐range electron transport across centimeter‐scale distances. The local pathways of the electrical currents in these filamentous microorganisms remain unresolved. Here, the electrical circuitry in a single cable bacterium is visualized with nanoscopic resolution using conductive atomic force microscopy. Combined with perturbation experiments, it is demonstrated that electrical currents are conveyed through a parallel network of conductive fibers embedded in the cell envelope, which are electrically interconnected between adjacent cells. This structural organization provides a fail‐safe electrical network for long‐distance electron transport in these filamentous microorganisms. The observed electrical circuit architecture is unique in biology and can inspire future technological applications in bioelectronics. Long before the age of microelectronics, a group of filamentous microorganisms named cable bacteria developed an electrical network within their own cell structure. In this work, the local electrical pathways for cable bacteria are revealed using conductive atomic force microscopy, showing a fail‐safe electrical structure conducted by parallel and electrically interconnected biological fibers.