A new type of power dressing, a prototype shirt that generates an electric current as a result of its wearer's movements, was unveiled by US nanotechnology researchers yesterday.

Zhong Lin Wang, a Regents professor in the school of materials science and engineering of the Georgia Institute of Technology, Atlanta, has developed yarns made from nanofibres that produce an electrical charge when rubbed against one another.

The nanofibres utilise the coupled piezoelectric and semiconducting properties of zinc oxide nanostructures, which, if flexed, produce small electrical charges.

"The two fibres scrub together just like two bottle brushes with their bristles touching, and the piezoelectric-semiconductor process converts the mechanical motion into electrical energy," said Wang

The fibre-based generator would be an economical and simple way to harvest energy from physical movement Wang claimed. He argued that combining fibres in double or triple layers in clothing could produce a flexible, wearable power source that could generate current whilst walking, for example.

Once further developed, the material woven from these yarns could be used to power handheld electrical devices or medical implants such as pacemakers. In addition, researchers believe the fabric could be woven into curtains or tents to capture energy from sound vibration, wind motion or other mechanical energy.

To date, researchers have only captured tiny amounts of current from such nanogenerators but with improved design, Wang estimates a square metre of fabric, could in theory, generate 80milliwatts of power. The next stage of development is to combine multiple fibre pairs to increase current and voltage levels.

However, the most significant challenge for any power shirt would be washing it. Zinc oxide is sensitive to moisture, so it may be a while before products hit the shops.