from io9:
New nano-generators can turn mechanical energy – like that of flowing blood – into electricity needed to power nanobots.
The tiny generators are the brainchild of Dr. Yong Shi, a professor in the Mechanical Engineering Department at Stevens Institute of Technology. They make use of a technology known as piezoelectric nanofibers, which are minuscule wires that are able to harness nearby mechanical energy (basically the energy of motion) and turn it into electrical energy. Each wire measures half a millimeter long and just 60 billionths of a meter in diameter.