New Conducting Properties Discovered in Bacteria-Produced Wires
The discovery of a fundamental, previously unknown property of microbial nanowires in the bacterium Geobacter sulfurreducens that allows electron transport across long distances could revolutionize nanotechnology and bioelectronics, says a team of physicists and microbiologists at the University of Massachusetts Amherst.
Their findings reported in the Aug. 7 advance online issue of Nature Nanotechnology may one day lead to cheaper, nontoxic nanomaterials for biosensors and solid state electronics that interface with biological systems.
Lead microbiologist Derek Lovley with physicists Mark Tuominen, Nikhil Malvankar and colleagues, say networks of bacterial filaments, known as microbial nanowires because they conduct electrons along their length, can move charges as efficiently as synthetic organic metallic nanostructures, and they do it over remarkable distances, thousands of times the bacterium’s length.
Networks of microbial nanowires coursing through biofilms, which are cohesive aggregates of billions of cells, give this biological material conductivity comparable to that found in synthetic conducting polymers, which are used commonly in the electronics industry.
Lovley says, “The ability of protein filaments to conduct electrons in this way is a paradigm shift in biology and has ramifications for our understanding of natural microbial processes as well as practical implications for environmental clean-up and the development of renewable energy sources.”
The discovery represents a fundamental change in understanding of biofilms, Malvankar adds. “In this species, the biofilm contains proteins that behave like a metal, conducting electrons over a very long distance, basically as far as you can extend the biofilm.”
Tuominen, the lead physicist, adds, “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 human-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.”