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The Power of Hamster Wheels

Forget biomass and ethanol, the secret to solving the energy crisis might come down to a tapping finger — or a hamster wearing a jacket. (The usual stars of this blog, mice and rats, proved too darned lazy for this particular study, but more on that in a moment.)

"Using nanotechnology, we have demonstrated ways to convert even irregular biomechanical energy into electricity," Zhong Lin Wang, a Regent's professor in the Georgia Tech School of Materials Science and Engineering, was quoted in a release announcing the findings. "This technology can convert any mechanical disturbance into electrical energy."

And it means, theoretically, that the Blackberry, iPhone and other handheld cellular devices could someday be self-powered, running on the energy generated by their users' typing.

The study, funded by the Defense Advanced Research Projects Agency, the U.S. Department of Energy, the U.S. Air Force, and the Emory-Georgia Tech Center for Cancer Nanotechnology Excellence, is reported in the online version of the American Chemical Society journal Nano Letters.

Wang's research team has been developing its nanogenerators since 2005, and this study demonstrated that they can be powered by several kinds of irregular movements — from the vibration of vocal cords to the flapping of a wind-ruffled flag. The generators rely on zinc oxide wires, which are attached to the joint area of an index finger or the "jacket" worn by a hamster. The running of the hamster, or the drumming of the finger, flexes the polymer substrate in which the nanowires are anchored, thereby producing small amounts of alternating electrical current.

Even more applications are possible, Wang believes. The modules could be implanted in the body to garner energy from muscle movements or pulsating blood vessels, he said, and could even be used to power nanodevices that measure vital signs.

But the study wasn't all smooth-sailing. Wang's team first tried to outfit a rat with the yellow power-generating jacket, but discovered, alas, that the rodents just weren't very interested in running. So Wang's daughter suggested hamsters — but because they are nocturnal, the experiments had to occur after 11 p.m. Even the jacket had to be carefully tailored: tight enough to stay on and to wrinkle the nanogenerator substrate, but not too confining to restrict the hamster's exercise.

"We believe this is the first demonstration of using a live animal to produce current with nanogenerators," Wang said. "This study shows that we really can harness human or animal motion to generate current."