[Image]Nanowire generators could one day lead to medical devices powered by the patient's own heart.

A tiny, nearly invisible nanowire can convert the energy of pulsing, flexing muscles inside a rat's body into electric current, researchers at Georgia Institute of Technology have shown. Their nano generator could someday lead to medical implants and sensors powered by heartbeats or breathing.

Zinc oxide nanowires show the piezoelectric effect, producing electricity when they are under mechanical stress. Georgia Tech professor of materials science and engineering Zhong Lin Wang and his group first demonstrated these nanowire generators in 2005. Since then they have made devices that can harness the energy of a running hamster and tapping fingers, and have also combined their piezoelectric nanowires with solar cells.


In their latest work, published in the journal Advanced Materials, Wang's team shows that the nanogenerator works inside a live animal. The researchers deposited a zinc oxide nanowire on a flexible polymer substrate and encapsulated the device in a polymer casing to shield it from body fluids. It was then attached to a rat's diaphragm. The rodent's breathing stretched the nanowire, and the device generated four picoamperes of current at two millivolts. When attached to a rat's heart, the device gave 30 picoamperes at three millivolts.

This device, which the researchers recently reported in the journal Nature Nanotechnology, gives an output current of about 100 nanoamperes at 1.2 volts, producing 0.12 microwatts of power.

Src: [TechnologyReview]