Recent study carried out by UMass Amherst researchers has showed that
electric charges propagate along microbial nanowires of the microbe Geobacter
just as they do in carbon nanotubes.
Physicists affirmed
that injection of electrons at one end in the microbial nanowires lit up the
whole filament as the electrons propagated through the nanowire, similar to the
other highly conductive materials. The technique applied here is known as
electrostatic force microscopy (EFM). This technique has immense environment implications
as conversion of waste to biogas is possible by conducting electricity through these
wires. The nanowires permit Geobacter to live on iron and other metals in the
soil, significantly changing soil chemistry and playing an important role in
environmental cleanup. Microbial nanowires are also key components in the
ability of Geobacter to produce electricity, a novel capability that is being
adapted to engineer microbial sensors and biological computing devices.
In biological
materials, electrons typically move by hopping along discrete biochemical
stepping-stones that can hold the individual electrons. By contrast, electrons
in microbial nanowires are delocalized, not associated with just one molecule,
leading to metallic-like conductivity phenomena.
This investigation not only brings up an important new
principle in biology but also in materials science. Natural amino acids, when
arranged correctly, can propagate charges similar to molecular conductors. It
opens exciting opportunities for protein-based nanoelectronics due to the fact
that manipulating microbes for electrical application seems feasible. Efforts
are also directed towards building electronic sensors to detect environmental
contaminants and microbiological computers using Geobacter.
