Scientists in the USA claim they have found a way to generate electricity from “specially engineered viruses”.

The scientists say the viruses convert energy from the tap of the finger into an electric charge.

They tested the process with a generator the size of a postage stamp, which produces enough current to operate a small liquid-crystal display. It made about a quarter of the voltage of a triple A battery.

The experiment is the first time the “piezoelectric properties” of biological material have been harnessed, say researchers. Piezoelectricity is the accumulation of a charge in a solid when it is put under mechanical stress.

The scientists at the US Department of Energy’s Lawrence Berkeley National Laboratory say the “milestone” discovery could lead to tiny devices that harvest electrical energy from the vibrations of everyday tasks such as shutting a door or climbing stairs.

Seung-Wuk Lee, a UC Berkeley associate professor of bioengineering who worked on the research said: “More research is needed, but our work is a promising first step toward the development of personal power generators… for use in nano-devices and other devices based on viral electronics.

“We’re now working on ways to improve on this proof-of-principle demonstration.”

The scientists describe their work in a May 13 advance online publication of the journal Nature Nanotechnology.