DISPATCHES FROM THE FRONTIERS OF SCIENCE, TECHNOLOGY AND MEDICINEJOIN THE CONVERSATION ONLINE Visit Scientific American on Facebook and TwitterINSIDE- Ultracold molecules’ behavior revealed
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T E C HLive Wires
Scientists are decoding the
mysteries behind microbes’
electron-wicking nanowiresBacteria in the genus Geobacter look like
miniature kidney beans sprouting long, wire-
like tails—and it turns out these “nanowires”
really do conduct electricity. Scientists have
been studying such conductive bacteria for
decades, hoping to develop living technolo-
gy that can work safely inside the human
body, resist corrosion or even literally pull
electricity out of thin air. But to make this
practical, they first must unlock the myster y
of how these minuscule fibers actually
work—and a vigorous debate is shaping up.
Geobacter’ s conductive abilities were
discovered by Derek Lovley, a microbiolo-
gist at the University of Massachusetts
Amherst, who wanted to know how these
bacteria rid themselves of the electrons
produced during their energy-generation
process. Most microbes need to pass elec-
trons to adjacent oxygen molecules to
“breathe”—but Geobacter thrives in oxygen-
free environments. Lovley eventually real-
ized that these one-celled organisms pro-
duce long chains of proteins that carry the
electrons to nearby rust molecules, which
use the charged particles to transform into
magnetite. Other protein nanowires have
been discovered since, but Lovley thinks
one kind, called pili, plays a primary role.
The proteins that make up pili—called pil-
ins—are too small to investigate with tradi-
tional imaging technology, so Lovley dem-
onstrated their importance by removing
the gene for making pili. Without it, Geo-
TED KINSMAN bacter could no longer change rust intoScience Source© 2020 Scientific American © 2020 Scientific American