26 November 2018

Researchers at the Laboratory of Organic Electronics, Campus Norrköping, have 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.

Gábor Méhes
Gábor Méhes Photographer: Thor Balkhed
Adding bacteria 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 signal strength 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 bacterium Shewanella oneidensis into PEDOT:PSS, an electrically conducting polymer, on a substrate of carbon felt.

MCBF

The researchers 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 Daniel Simon, forskningsledare inom organisk bioelektronik, LOEDaniel Simon Photo credit Thor Balkhedresponse to arsenic, arabinose (a type of sugar) and organic acids, among others.

Living electrode

“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.

The article: PEDOT:PSS-based Multilayer Bacterial-Composite Films for Bioelectronics, Tom J. Zajdel, Moshe Baruch, Gábor Méhes, Eleni Stavrinidou, Magnus Berggren, Michel M. Maharbiz, Daniel T. Simon & Caroline M. Ajo-Franklin. Scientific Reports 8, 2018. DOI 10.1038/s41598-018-33521-9

Translation George Farrants

Contact

LOE

Latest news from LiU

Four persons in chairs on a stage.

AI can boost financial decision making

Do you have limited financial knowledge, or prefer not to think about financial issues? Then there is great potential that AI can help, according to LiU researcher Kinga Barrafrem.

Nathalie Hallin and Hajdi Moche in conversation.

Religious people are not more generous – with one exception

Believers are no more generous than atheists – at least as long as they don’t know what the recipient believes in. This is the conclusion of a study carried out at LiU

Lots of cables connected to a computer.

Sweden to host European AI Factory

Sweden has been selected to host one of seven European AI Factories that will strengthen the EU’s competitiveness in the field. The AI Factory combines a state-of-the-art AI-optimised supercomputer with support for education, research and innovation.