Self-Powered Nanotech; January 2008; Scientific American Magazine; by Zhong Lin Wang; 6 Page(s)

The watchmaker in the 1920s who devised the self-winding wristwatch was on to a great idea: mechanically harvesting energy from the wearer's moving arm and putting it to work rewinding the watch spring.

Today we are beginning to create extremely small energy harvesters that can supply electrical power to the tiny world of nano scale devices, where things are measured in billionths of a meter. We call these power plants nano generators. The ability to make power on a minuscule scale allows us to think of implantable biosensors that can continuously monitor a patient's blood glucose level, or autonomous strain sensors for structures such as bridges, or environmental sensors for detecting toxins--all running without the need for replacement batteries. Energy sources are desperately needed for nano robotics, microelectromechanical systems (MEMS), homeland security and even portable personal electronics. It is hard to imagine all the uses such infinitesimal generators may eventually find.