Researchers at the Stevens Institute of Technology in New Jersey,
USA, have produced electricity from mushrooms in a process involving
bacteria and swirls of graphene nanoribbons. The ‘bionic’ mushrooms are
actually common white button mushroom that have been supercharged with
3D printed clusters of densely packed cyanobacteria to produce
electricity that is then collected by the nanoribbons.
The team engineered an artificial symbiosis between the mushrooms and
cyanobacteria, with the mushroom providing shelter, moisture and
nutrients, and the bacteria offering energy through photosynthesis.
Graphene nanoribbons printed alongside the bacteria help to capture
electrons released by the microbes, producing bio-electricity. As well
as producing an environmentally friendly source of energy, this advance
in bacterial nanobionics, reported in Nano Letters [Joshi et al. Nano Lett. (2018) DOI: 10.1021/acs.nanolett.8b02642],
increases our knowledge of the biological machinery of cells, and also
how to use such complex molecular machinery to produce new technology in
areas including defense, healthcare and the environment.
An electronic ink containing graphene nanoribbons was 3D printed onto
the cap of a living mushroom in a branched pattern, before printing a
bio-ink containing cyanobacteria onto the cap in a spiral pattern. This
intersected with the electronic ink at multiple places, and it is at
these points that electrons are able to transfer through the outer
membranes of the bacteria to the conductive network of nanoribbons.
Shining a light on the mushrooms activated cyanobacterial
photosynthesis, generating a current of around 65 nanoAmps. While not
strong enough to power electronic devices, an array of bionic mushrooms
could generate enough current to light up an LED.
“We showed for the first time that a hybrid system can
incorporate an artificial collaboration, or engineered symbiosis,
between two different microbiological kingdoms”Sudeep Joshi
The
amount of electricity produced by the bacteria is based on the density
and alignment with which they are packed, and the 3D printing meant they
could assemble them to boost their electricity-producing activity by
eight times more than the casted cyanobacteria. The mushrooms acted as a
suitable environmental substrate with functionality of nourishing the
energy producing cyanobacteria. As co-leader Sudeep Joshi said, “We
showed
for
the first time that a hybrid system can incorporate an artificial
collaboration, or engineered symbiosis, between two different
microbiological kingdoms”.
The research helps toward new applications that integrate bacteria
with nanomaterials to produce bio-hybrids and the next generation of
bionic architectures. The team are now exploring ways to generate higher
currents with their system, and how their 3D printing approach could
organize other bacterial species in complex arrangements to perform
functions such as bioluminescence.