Bacterial nanowires could create conducting organic materials
Researchers from the University of Massachusetts Amherst have observed a nifty species of bacteria using a biofilm to conduct an electrical charge, just like a metal wire. The find could lead to naturally-formed nanomaterials.
The bacteria is called Geobacter sulfurreducens and it uses a matrix of nanowires (protein filaments), spread throughout a thick biofilm (a cohesive aggregate of billions of cells), to transfer electrons onto iron oxides.
It does this to “breathe”. The anaerobic organism grows on iron minerals in aquatic soils and sediments, and harnesses those oxides in the same way that humans breath oxygen.
The microscopic critter can also extend the biofilm by centimetres, thousands of times the bacterium's length. “What Geobacter can do with its nanowires is akin to breathing through a snorkel that's 10 kilometers long,” said physicist Nikhil Malvankar.
The researchers say that this is the first time that a metallic-like conduction of electrical charge along a protein filament has been observed in the natural world. Not only that, but it’s incredibly powerful — moving charge as efficiently as the synthetic organic metallic nanostructures that are used in the electronics industry.
Mark Tuominen, the lead physicist, said, “This discovery not only puts forward an important new principle in biology, but in materials science. We can now investigate a range of new conducting nanomaterials that are living, naturally occurring, nontoxic, easier to produce and less costly than man-made.”
"They may even allow us to use electronics in water and moist environments. It opens exciting opportunities for biological and energy applications that were not possible before.”
Lead microbiologist Derek Lovley quipped, “We’re basically making electronics out of vinegar. It can’t get much cheaper or more ‘ green' than that.”