Electric virus powers liquid crystal display in piezoelectric breakthrough
Scientists at the Lawrence Berkeley National Laboratory have developed a means of converting mechanical energy into electrical energy using a harmless, specially engineered virus
Scientists at the Lawrence Berkeley National Laboratory have
developed a means of converting mechanical energy into electrical energy
using a harmless, specially engineered virus. By simply tapping a
finger on a virus-coated electrode the size of a postage stamp, the
scientists were able to produce enough current to drive a liquid crystal
display, albeit a very small one. The scientists claim that this is the
first time that the piezoelectrical properties of a biological material
have been harnessed.
To recap, piezoelectricity is the electrical charge that can build up
in solid materials when they experience mechanical stress. It's a
principle that could be put to use to harvest energy from common,
everyday events like the fall of a shoe against a sidewalk, the closing of a door, or even typing with a notebook.
Because many of the piezoelectric materials in use today are toxic,
the researchers wondered whether a particular virus known as M13, common
to laboratories all over the world, might be piezoelectric. As the
virus targets bacteria and is harmless to people, the scientists
theorized that it might one day encourage more widespread use of
piezoelectrics.
To determine whether the M13 bacteriophage was indeed piezoelectric, a
film of the virus was exposed to an electrical field. When observed
through a specialized microscope, helical proteins that coat rods of the
virus were observed to move, confirming a piezoelectric effect.
Left to right, Byung Yang Lee, Seung-Wuk Lee, and Ramamoorthy Ramesh are among the scientists behind the research
The scientists found that they were able to further boost the charges
induced in the virus by genetically engineering them with an extra four
negatively charged amino acid residue at one end of these helical
proteins.
An added benefit of using the virus, according to the scientists, is
that that they self-arrange into the film that enables generation to
take place, and by infecting bacteria, the virus can be made to
reproduce, generating millions of copies over night. (This kind of
self-arrangement and replication may one day prove handy for
self-assembling nanotechnology, the scientists surmise). The charge was
further boosted by stacking these virus films into layers, with a stack
20 layers thick demonstrating the strongest piezoelectric effect.
The system developed by the scientists had a potential difference of
400 millivolts, capable of generating an electrical current of six
nanoamperes. A demo of the virus-powered LCD can be seen near the end of
the video below.
