Printable bacteria used for low-energy biosensors

UK researchers have used bacteria as a solar-harvesting ink to print paper-based disposable biosensors.


(Credit: Imperial College London)

The biosensors are powered by Cyanobacteria, photosynthetic micro-organisms that produce small amounts of energy over a period of around 100 hours. Using an inkjet printer, the researchers created precise patterns of the bacteria on to paper, alongside patterns of electrically conductive carbon nanotubes.

The resulting paper sensors could be used to create wallpaper for short-term environmental monitoring or disposable medical devices for patients with conditions such as diabetes. Published in the journal Nature Communications, the work was carried out by a multidisciplinary team from Imperial College London, the University of Cambridge and Central Saint Martins.

“Imagine a paper-based, disposable environmental sensor disguised as wallpaper, which could monitor air quality in the home,” said Dr Marin Sawa, a co-author from the Department of Chemical Engineering at Imperial College London.

“When it has done its job it could be removed and left to biodegrade in the garden without any impact on the environment.”

The work is an example of the fast-growing are of microbial biophotoltaics (BPV), where cyanobacteria and other algae use photosynthesis to convert light into an electrical current using water as the source of electrons. According to the researchers, BPVs have previously been costly to produce and difficult to scale up. Using an off-the-shelf inkjet printer to construct them makes the technology more accessible.

“Paper-based BPVs are not meant to replace conventional solar cell technology for large-scale power production, but instead, could be used to construct power supplies that are both disposable and biodegradable,” said study co-author Dr Andrea Fantuzzi, from Imperial’s Department of Life Sciences.

“Furthermore, this approach has the potential to be very cost-effective, which could also pave the way for its use in developing countries with limited healthcare budgets and strains on resources.”

The BPV unit produced for the study is about the size of small tablet device and can power a simple digital clock or a low-wattage LED bulb. The next phase of the research will see the team scale up their proof-of-concept to A4 size to determine the electrical output on a larger scale.