As cool as the iPod is, there are limitations.

Zhong Lin Wang, a professor and nanotechnology researcher at the Georgia Tech believes that within five years, we can remove some of them. According to Macworld UK, Wang and his colleagues are developing a "power shirt," a nanotechnology-based device that could harvest the energy generated by human movements and turn the clothing into a flexible, foldable and wearable power source for the iPod.

Wang, a Regents professor for the Georgia Tech's School of Materials Science and Engineering, stated this week that his group is looking into nanotechnology to try to help soldiers, hikers and other people harness the energy generated by physical motion and convert it into usable electrical power.

"For the last few years, we've been looking for energy harvesting technology," Wang said. "Body movements. Heart beating. Blood flow. Sonic waves created when you're talking. These are all energies available in our environment. We wanted to know how to convert them into use. Body movement is the most conventional choice."

The process of creating a power shirt would involve weaving numerous pairs of textile fibers covered with zinc oxide nanowires into a shirt that could enable the wearer's body movements to be converted into energy for portable power devices. The nanowire-covered fibers could also be woven into curtains, tents or other structures to capture energy from sound vibrations or wind motions.

Wang noted that the fibre pairs being used by him and his team of researchers are each one centimetre long and can produce four nanoamperes of current and an output voltage of about four millivolts. Wang then went on to describe a power shirt, which could include millions of the fiber pairs on the one square meter of space on the shirt, which would be necessary to harvest enough energy to power an iPod. Wang added that the nanowires would stick out of the fibers like bristles on a brush and rub against each other, creating electricity via the nanowires.

The shirt could be connected to an electronic device via a separate wire, enabling the device to be powered directly by the wearer's movements, Wang said.

To date, the researchers involved have developed more than 200 nanofibers along with the first prototype of a power shirt.

"I think we are five years away from this [becoming viable], because there are a lot of technical challenges to overcome," he said. "How do we link all these fibres together? How do we protect them when the shirt is out in the rain? How do we make sure the power is effectively stored and [then] output?"

The shirt would also provide additional challenges such as finding an appropriate means to wash it. Zinc oxide is sensitive to moisture and these materials would have to be protected from both the wash cycles as well as rain storms.

Georgia Tech said the nanogenerator research work was sponsored by the National Science Foundation, the US Department of Energy and the Emory-Georgia Tech Nanotechnology Center for Personalized and Predictive Oncology.