Energy

Carbon nanotubes boost efficiency in "nanobionic" bacterial solar cells

Carbon nanotubes can help photosynthetic bacteria produce electricity more efficiently, in a new study from EPFL
Carbon nanotubes can help photosynthetic bacteria produce electricity more efficiently, in a new study from EPFL

Engineers at EPFL have found a way to insert carbon nanotubes into photosynthetic bacteria, which greatly improves their electrical output. They even pass these nanotubes down to their offspring when they divide, through what the team calls “inherited nanobionics.”

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

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3 comments
Karmudjun
Now that is some exciting research. Imagine humans mucking around with biology to the point of inserting desired structures inside bacteria. But wait - we have been doing just that with our antibiotics - we have engineered bacteria to encode other bacteria's antibiotic resistance into the bacteria that plague is - now we have antibiotic resistant bacteria even though it was not our intention. But this is different - what could go wrong? We get electricity from the bacteria, we grow them and utilize them - and then what? How do we keep the bacteria from causing us harm, proliferating in the wild and harming beneficial organisms - or organelles? Just playing devils advocate.
HortonTheWho
Questions to answer;
1.Power Output
2.Power to Produce full apparatus, carbon nanotubes, stainless/aluminum container for liquid, freshwater used(power to clarify such water)
3.Ease of use, lifespan of bacteria, waste by-products
4.Scalability
5.Cost per kWh
6. Square meter space used and temperature range requirements
Every ‘renewable’ needs to answer similar questions before receiving anything beyond the smallest grant. True range of potential, scale, and drawbacks should never be an afterthought.
TpPa
sweet until the bacteria gets out into the wild, and all living creatures start generating electricity & knock our hearts off line.