Electronics becomes green / Invention of nanowires that generate electricity from air

Eviralnews, citing Interesting Engineering, researchers from the University of New South Wales (UNSW) were able to direct the electric current and control it using air humidity by engineering the protein strands produced by bacteria.

This interdisciplinary research consisting of protein engineering and nanoelectronics can one day help scientists develop “green electronics”.

Today's ubiquitous electronic devices are manufactured using energy-intensive processes and highly toxic components that are necessary to facilitate the movement of electrons within the device and to perform work.

On the other hand, many events in nature also require electron movement. For example, in the process of photosynthesis that plants use to make their food, chlorophyll moves electrons in different protein molecules. Bacterial systems also transport electrons across membranes using conductive strands called nanowires.

Engineering bacteria for nanowires

Bacterial nanowires can conduct electricity and potentially be used to develop sensing systems. However, these nanowires are difficult to repair after being harvested from bacteria and thus have limited functionality.

“Lorenzo Travaglini” one of the presenters of this research says: To overcome these limitations, we made a string using the bacteria “E. coli” “E. coli” genetically engineered.

He added: We have DNA. coli so that the bacteria would not only produce the proteins they needed to survive, but also make the specific protein we designed. Then we engineered these specific proteins and assembled them into nanowires in the laboratory.

Interestingly, the additional molecule that makes the nanowires highly conductive is haem: an iron-based circular structure found in animal blood that transports oxygen to different parts of the body.

Generating electricity from air

The studies of these researchers on bacterial nanowires showed that when heme molecules are arranged close to each other, they can also transfer electrons. Travaglini and his colleagues incorporated heme into their engineered strands with the hope that if the electrons were close enough to the heme, they would jump between the heme molecules.

By measuring the conductivity of the filaments in the presence and absence of heme molecules, the researchers confirmed that the iron-based molecule causes protein conductivity. Extensive tests have shown that the electric current is stronger when the ambient humidity is between 20 and 30%.

Repeating the experiments with increasing amounts of conductive material between the electrodes confirmed that moisture creates a charge gradient across the material and forms an additional current without applying an additional potential.

The researchers then developed a moisture sensor that generates an electrical current when breath is passed over it. They are now investigating how to regulate the changing properties of their proteins by changing the heme structure or the strand environment. The scientists are now testing light-sensitive molecules to facilitate electron transfer.

Travaglini emphasized that this research is still in its early stages and there is still a long time before it becomes a part of everyday electronics.

The results of this research have been published in Small magazine.