mercredi 16 mai 2012

Scientists Generate Electricity from Viruses

Berkeley Lab is perched on a hill overlooking ...
Berkeley Lab is perched on a hill overlooking the Berkeley central campus and San Francisco Bay. (Photo credit: Wikipedia)
When people get a cold or the flu, they tend to experience a lack of energy. But what if viruses could actually generate energy — not to power your body, but to charge your electronic devices?
That’s the idea behind a new electric generator developed by scientists at the U.S. Department of Energy‘s Lawrence Berkeley National Laboratory. The scientists coated a postage-stamp-sized electrode with specially engineered, harmless viruses that, when tapped, generated enough electricity to power a small LCD display. Their research was published online May 13 in the journal Nature Nanotechnology.
The scientists are exploiting a principle known as piezoelectricity — the generation of energy through mechanical stress, specifically pressure or vibrations. Piezoelectricity was first identified more than 130 years ago and is used in many common devices, but this is the first time that it has been generated by biological materials. The piezoelectric devices that are currently on the market rely upon toxic materials such as lead and lithium.
According to Berkeley Lab, this discovery could lead to innovations like tiny electric generators you could place in your shoes that would help charge your cell phone or other electronic devices with every step you take. Similarly, piezoelectric generators placed on stairs could help power lights and other nearby electronics.
“More research is needed, but our work is a promising first step toward the development of personal power generators, actuators for use in nano-devices, and other devices based on viral electronics,” corresponding author Seung-Wuk Lee said in a prepared statement.
In looking for a way to eliminate the need for toxic substances in piezoelectric devices, the scientists turned to a biological solution. They used a genetically engineered variant of the M13 bacteriophage virus, which is harmless to humans (it only infects bacteria) and is also used in labs in recombinant DNA processes. The M13 virus self-replicates millions of times over the course of just a few hours, so it is plentiful enough and sustainable for piezoelectric applications.
The scientists had already studied the unmodified M13 virus and observed minor levels of the piezoelectric effect. In order to boost the voltage the virus generates, the scientists genetically modified it by adding four negatively charged amino acids to one of the virus’s proteins.
The resulting viruses, when coated on the electrode, didn’t generate a huge amount of electricity — just six nanoamperes, the equivalent of about one-quarter the volage supplied by a AAA battery — but it was a start.
“We’re now working on ways to improve on this proof-of-principle demonstration,” Lee said. “Because the tools of biotechnology enable large-scale production of genetically modified viruses, piezoelectric materials based on viruses could offer a simple route to novel microelectronics in the future.”
Source : Forbes

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