As teensy nanotech devices get even tinier, the question of how to supply them with power becomes more pressing. Zhong Lin Wang, a nano-engineer at the Georgia Institute of Technology in Atlanta, is committed to finding the answer. As he described in a January Scientific American article, these devices (measured in nanometers, or billionths of a meter) could rely on nanoscale power plants, which would harvest waste energy from the ambient atmosphere or even from the human body. Now Wang's team has a new addition to the nanogenerator family: zinc oxide wires that produce an alternating current when stretched and released like a rubber band. (Wang is pictured holding a large-scale prototype at the left.)

The new approach, described today in Nature Nanotechnology, has several advantages over earlier techniques, Wang says. For one, it avoids the mechanical scrubbing action that characterized some earlier generators, which means it's less likely to wear down. And the simplicity of the concept lends itself better to mass production. The entire device is covered by a flexible polymer, Wang adds, so it can be embedded in soft materials such as clothing or even muscles, meaning that getting your blood moving by going for a brisk walk or hitting the gym might one day get some electrons moving as well.

Credit: Gary Meek/Georgia Tech