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Future of computing? |
In
order to create new and more efficient computers, medical devices, and other
advanced technologies, researchers are turning to nanomaterials: materials
manipulated on the scale of atoms or molecules that exhibit
unique properties.
Graphene
-- a flake of carbon as thin as a single later of atoms -- is a revolutionary
nanomaterial due to its ability to easily conduct electricity, as well as its
extraordinary mechanical strength and flexibility. However, a major hurdle in
adopting it for everyday applications is producing graphene at a large scale,
while still retaining its amazing properties.
Graphene
is extracted from graphite, the material found in an ordinary pencil. At
exactly one atom thick, graphene is the thinnest -- yet strongest --
two-dimensional material known to researchers. Scientists from the University
of Manchester in the United Kingdom were awarded the 2010 Nobel Prize in
Physics for their discovery of graphene; however, their method of using sticky
tape to make graphene yielded only small amounts of the material.
"For
real applications you need large amounts," Meyer says. "Producing
these bulk amounts is challenging and typically results in graphene that is
thicker and less pure. This is where our work came in."
In
order to produce larger quantities of graphene materials, Meyer and her
colleagues started with a vial of graphite. They exfoliated the graphite --
shedding the layers of material -- to produce graphene oxide (GO), which they
then mixed with the bacteria Shewanella. They let the beaker of bacteria and
precursor materials sit overnight, during which time the bacteria reduced the
GO to a graphene material.
"Graphene
oxide is easy to produce, but it is not very conductive due to all of the
oxygen groups in it," Meyer says. "The bacteria remove most of the
oxygen groups, which turns it into a conductive material."
While
the bacterially-produced graphene material created in Meyer's lab is
conductive, it is also thinner and more stable than graphene produced
chemically. It can additionally be stored for longer periods of time, making it
well suited for a variety of applications, including field-effect transistor
(FET) biosensors and conducting ink. FET biosensors are devices that detect
biological molecules and could be used to perform, for example, real-time
glucose monitoring for diabetics.
The
bacterially produced graphene material could also be the basis for conductive
inks, which could, in turn, be used to make faster and more efficient computer
keyboards, circuit boards, or small wires such as those used to defrost car
windshields. Using conductive inks is an "easier, more economical way to
produce electrical circuits, compared to traditional techniques," Meyer
says. Conductive inks could also be used to produce electrical circuits on top
of nontraditional materials like fabric or paper.
READ MORE: Technique identifies electricity-producing bacteria
READ MORE: Technique identifies electricity-producing bacteria
"Our
bacterially produced graphene material will lead to far better suitability for
product development," Meyer says. "We were even able to develop a
technique of 'bacterial lithography' to create graphene materials that were
only conductive on one side, which can lead to the development of new, advanced
nanocomposite materials."
See:
Posted by Dr. Tim Sandle, Pharmaceutical Microbiology
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