By Michael Irving
September 18, 2022
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Carbon nanotubes can help photosynthetic bacteria produce
electricity more efficiently, in a new study from EPFL (Photo credit: Depositphotos)
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Solar cells are the leading source of renewable energy, but
their production has a large environmental footprint. As with many things, we
can take cues from nature about how to improve our own devices, and in this
case photosynthetic bacteria, which get their energy from sunlight, could be
used in microbial
fuel cells.
In the new study, the EPFL team gave these bacteria a boost
by inserting carbon
nanotubes – tiny rolled-up sheets of graphene, a material that’s
famously conductive. The nanotube-loaded bugs were able to produce up to 15
times more electricity than their non-edited counterparts from the same amount
of sunlight.
Getting the nanotubes inside the bacteria is no easy feat,
the team says, but they managed it by decorating their surface with positively
charged proteins. This attracts them to the outer membranes of the bacteria,
which are negatively charged. It worked in two species of bacteria, Synechocystis and Nostoc,
which have very different shapes.
But perhaps the most intriguing part is that when the bacteria
divide, they pass on the carbon nanotubes – and as such, the better electrical
properties – to the new cells. That does diminish over time, however, as the
concentration of carbon nanotubes is spread out between more and more cells,
but it’s an interesting proof-of-concept of what the team calls inherited
nanobionics.
“It’s like having an artificial limb that gives you
capabilities beyond what you can achieve naturally,” said Professor Ardemis
Boghossian, corresponding author of the study. “And now imagine that
your children can inherit its properties from you when they are born. Not only
did we impart the bacteria with this artificial behavior, but this behavior is
also inherited by their descendants. It's our first demonstration of inherited
nanobionics.”
The team says that as well as producing new photovoltaic
devices, this technique for inserting carbon nanotubes could also be useful for
monitoring the inner workings of bacteria, or for tracing lineage between
generations in a population.
The research was published in the journal Nature
Nanotechnology.
Source: EPFL