Georgia Institute of Technology researchers have demonstrated that a hamster wearing a jacket onto which nanogenerators are attached can produce electricity as the animal runs on its wheel. Using the same nanotechnology these researchers have also generated electrical current from a tapping finger - moving the users of BlackBerry devices, cell phones and other handhelds one step closer to powering them with their own typing.
Zhong Lin Wang, a Regent's professor in the Georgia Tech School of Materials Science and Engineering said "Using nanotechnology, we have demonstrated ways to convert even irregular biomechanical energy into electricity. This technology can convert any mechanical disturbance into electrical energy."
The study demonstrates that nanogenerators (tiny wires a fraction of the size of a human hair and made out of zinc oxide) can be driven by irregular mechanical motion, such as the vibration of vocal cords, flapping of a flag in the breeze, tapping of fingers or hamsters running on exercise wheels. Scavenging such low-frequency energy from irregular motion is significant because much biomechanical energy is variable, unlike the regular mechanical motion used to generate most large-scale electricity today.
"Millions of our piezoelectric nanowires will be needed to produce enough energy to power a consumer electronic device like a Blackberry," said Wang. "But our demonstration here has proven the principle that any type of muscle movements in humans or animals can be used to generate power." Wang estimates that powering a handheld device such as a Bluetooth headset would require at least thousands of these single-wire generators, which could be built up in three-dimensional modules.
To make their generators, Wang's research team encapsulated single zinc oxide wires in a flexible polymer substrate, the wires anchored at each end with an electrical contact, and with a Shottky Barrier at one end to control current flow. They then attached one of these single-wire generators to the joint area of an index finger, or combined four of the single-wire devices to the hamster's "jacket". The tapping of the finger, or running and scratching of the hamster flexed the substrate in which the nanowires were encapsulated, producing tiny amounts of alternating electrical current. Integrating four nanogenerators on the hamster's jacket generated up to 0.5 nanoamps; less current was produced by the single generator on the finger.
Wang also believes his modules could be implanted into the body to harvest energy from muscle movements or pulsating blood vessels. In the body, they could be used to power nanodevices to measure blood pressure or other vital signs.
"We believe this is the first demonstration of using a live animal to produce current with nanogenerators," Wang added. "This study shows that we really can harness human or animal motion to generate current."
Top Image: a hamster wearing a jacket with attached nanogenerators. Source: Zhong Lin Wang
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