Living electrodes with bacteria and organic electronics

November 26, 2018, Linköping University
Gábor Méhes, researcher at Linköping University.Photo credit Thor Balkhed

Researchers at the Laboratory of Organic Electronics, Linköping University, have together with colleagues at the Lawrence Berkeley National Laboratory in Berkeley, California, developed a method that increases the signal strength from microbial electrochemical cells by up to twenty times. The secret is a film with an embedded bacterium: Shewanella oneidensis.

Adding to electrochemical systems is often an environmentally sensitive means to convert chemical energy to electricity. Applications include water purification, bioelectronics, biosensors, and for the harvesting and storage of energy in fuel cells. One problem that miniaturisation of the processes has encountered is that a high requires large electrodes and a large volume of liquid.

Researchers at Linköping University, together with colleagues at the Lawrence Berkeley National Laboratory in Berkeley, California, USA, have now developed a method in which they embed the electroactive Shewanella oneidensis into PEDOT:PSS, an electrically conducting polymer, on a substrate of carbon felt.

The call the result a "multilayer conductive bacterial-composite film," abbreviated as MCBF. Microscopic analysis of the film shows an interleaved structure of bacteria and conducting polymers that can be up to 80 µm thick, much thicker than it can be without this specific technique.

"Our experiments show that more than 90% of the bacteria are viable, and that the MCBF increases the flow of electrons in the external circuit. When our film is used as anode in microbial electrochemical cells, the current is 20 times higher than it is when using unmodified anodes, and remains so for at least several days," says Gábor Méhes, researcher at Linköping University and one of the lead authors of the scientific article recently published in Scientific Reports.

Previous work has tested, among other things, carbon nanotubes to increase the surface area at the anode, but the results were poor.

The possibility to couple biological processes with readable electrical signals is also valuable, for example for environmental sensors which require rapid response times, low energy consumption, and the ability to use many different receptors. Researchers have recently demonstrated how to use Shewanella oneidensis to produce electrical currents in response to arsenic, arabinose (a type of sugar) and organic acids, among others.

"This technology represents a type of "living electrode" where the electrode material and the bacteria are amalgamated into a single electronic biofilm. As we discover more about the essential role that bacteria play in our own health and wellness, such living electrodes will likely become versatile and adaptable tools for developing new forms of bioelectronic technologies and therapies," says Daniel Simon, principal investigator in Organic Bioelectronics at the Laboratory of Organic Electronics.

Explore further: Conducting shell for bacteria

More information: Tom J. Zajdel et al. PEDOT:PSS-based Multilayer Bacterial-Composite Films for Bioelectronics, Scientific Reports (2018). DOI: 10.1038/s41598-018-33521-9

Related Stories

Conducting shell for bacteria

June 27, 2017

Under anaerobic conditions, certain bacteria can produce electricity. This behavior can be exploited in microbial fuel cells, with a special focus on wastewater treatment schemes. A weak point is the dissatisfactory power ...

Building a better microbial fuel cell—using paper

February 6, 2017

The concept behind microbial fuel cells, which rely on bacteria to generate an electrical current, is more than a century old. But turning that concept into a usable tool has been a long process. Microbial fuel cells, or ...

A major step forward in organic electronics

January 12, 2018

Researchers at the Laboratory of Organic Electronics, Linköping University, have developed the world's first complementary electrochemical logic circuits that can function stably for long periods in water. This is a highly ...

Recommended for you

Using machine learning to design peptides

December 10, 2018

Scientists and engineers have long been interested in synthesizing peptides—chains of amino acids responsible for conducting many functions within cells—to both mimic nature and to perform new activities. A designed peptide, ...

Biomimetic strategy leads to strong, recyclable rubber

December 10, 2018

Inspired by nature, Chinese scientists have produced a synthetic analogue to vulcanized natural rubber. Their material is just as tough and durable as the original. In the journal Angewandte Chemie, they reveal the secret ...

Custom-made artificial mother-of-pearl

December 10, 2018

Natural mother-of-pearl, such as mussels, is one of the hardest, most stable and stiff natural materials. Researchers have always been fascinated by it. The structure of mother-of-pearl is exquisite under the electron microscope; ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.