Revolution? Bacterial nanowires produce current of humid air

Scientists from the University of Massachusetts in Amherst have created a generator that runs from natural humidity. It produces a small but constant current by protein nanowires derived from bacteria.

the Amazing result was published in the prestige science journal Nature by a group led by Jun Yao (Jun Yao).

Different research group had previously demonstrated devices generating electricity upon contact with moisture (and the physical mechanisms of this phenomenon only being studied). Thus, the authors provide links to six scientific papers on the subject. But until now it was limited to relatively short (less than 50 seconds) electric pulses.

this was changed by the bacteria Geobacter sulfurreducens. It produces a protein filament nanometer thickness. If this thread is placed between electrodes, then, as found by the experimenters, it spontaneously flows an electric current.

As is known, the current is an ordered flow of charged particles, usually electrons. But where in the protein the “wire” come from the moving electrons and the potential difference, leading them in motion?

After a series of experiments, physicists found that this fact does not depend on the electrode material. So he cannot be a “supplier” of electrons. They ruled out the possibility that the “wire” gradually dissolves, releasing the electrons. The lighting in here was also nothing to do with it, because the device worked in the dark. But when the scientists placed it in a room with less humidity of air, the current decreased markedly.

Further research led the researchers to conclude that protein strands absorb moisture from the air, thus creating a self-sustaining drop of moisture between different ends of the strands. Part of the water molecule splits into ions and electrons that constitute the current.

best of all, this scheme operates at a humidity of 45%. But it continues to function even in the dry as in the desert or, on the contrary, extremely humid air.

revolution bacterial nanowires produce current of humid air 1a Few established authors cells should be enough to power the smartphone.Photo UMass Amherst/Yao and Lovley labs.

Recall that the “workhorse” of the new device is a film of protein nanowires produced by G. sulfurreducens. Beneath it and above it are the electrodes, and the top closes only part of the film so as not to disturb it to absorb moisture.

a Layer with a thickness of seven microns generates a voltage of 0.5 volt and a current density of about 17 microamps per square centimeter. As the authors suggest, there is the role of chemical composition and electrical conductivity of filaments and the presence between them then.

Combining several of these elements, you can increase the voltage and current. 17 such devices will provide voltage to 10 volts. This very good result: this voltage is sufficient to power the smartphone.

the generator the authors called Air-gen.

“We literally generate electricity from the air, says Yao. — Air-gen generates [environmentally] clean energy 24 hours a day.”

the developers, of course, has big plans for the introduction of technology. So, they hope to create “eternal batteries” for wearable electronics. Also power generating film could cover the walls of houses.

“bottleneck” there may be except itself, the original G. sulfurreducens, which is uncomfortable to grow for the production of nanofibers. Therefore, researchers have already created genetically modified E. coli coli, generating the same thread. They reported about it in a scientific publication, a Preprint of which is available on the website biorXiv.org.

“This is only the beginning of a new era of electronic devices based on protein,” — said Yao.

However, to open the champagne too early. The mechanism of Air-gen has not been studied thoroughly, and may with him it is not so simple.

Explain that there is a fundamental physical law called the second law of thermodynamics. Among other things it States that any power generator works on differential temperature or other physical quantities.

for Example, a solar cell operates due to the fact that its surface is cooler than the Sun, and anticolana — due to the fact that it is warmer than outer space. What is the differential provides Air-gen and how long it actually is able to support the generation? The answer to this, apparently, is not quite clarified Yao question depends the future of technology.

In any case, the findings and pilot scheme, the authors must undergo a comprehensive review by other research groups before we can talk about a new word in the energy sector.

By the way, earlier “Conduct.Science” (nauka.vesti.ru) wrote about how battery work on live bacteria, including solar.

Text: To.Science