Cable bacteria achieve centimeter-scale electron transport through periplasmic fibers containing intertwined nanoribbons composed of axially aligned oligomeric nickel bis(dithiolene) complexes with an ethene tetrathiolate configuration, forming a biologically unprecedented one-dimensional metal-organic framework that attains conductivities of 10²-10⁴ S cm⁻¹, exceeding synthetic polymeric analogs by two orders of magnitude.

Multi-cellular cable bacteria have evolved a unique machinery that efficiently transports electrons across centimetre-scale distances. Currents flow through a parallel network of periplasmic fibres, which display an extraordinary conductivity for a biological material. However, the conduction mechanism remains elusive as the molecular structure of the fibres has not been resolved. Here, we demonstrate that each fibre embeds a bundle of intertwined nanoribbons, which are built from Nickel Bis(Dithiolene) (NiBiD) repeat units that are formed by linking nickel centres with ethenetetrathiolate ligands. The planar and conjugated NiBiD complexes are aligned and stacked to form an elongated supramolecular coordination network, thus explaining the observed organo-metal electronic properties of the fibres. Our results hence demonstrate that biology is capable of producing extensive metal organic frameworks. These structures enable highly conductive one-dimensional conduits, ensuring efficient charge transport over macroscale distances, thus providing a novel design principle for bio-based, sustainable organo-electronic materials.