With their ability to generate electricity from mechanical stress, piezoelectric systems made from synthetic materials are great and all, but you know what might be even better? Piezoelectric systems made from natural materials. Scientists have made a promising discovery in this area, pinpointing a biomolecule that produces an impressive amount of electricity when tapped or squeezed.

Piezoelectric materials are already used in specialized applications, like mobile phone speakers, motion detectors in cars and video game controllers. But the synthetic materials used in these systems, with ceramics being a prime example, often contain toxic elements like lead or lithium.

Now scientists at the University of Limerick have found a candidate that could offer a cleaner and cheaper way of doing things: a biomolecule called glycine. Glycine is an amino acid that occurs naturally in forestry and agricultural residues and can be produced for less than one per cent of currently used piezoelectric materials. But most importantly, the team found that it can generate meaningful amounts of electricity with minimal effort.

"It is really exciting that such a tiny molecule can generate so much electricity," says lead author and post-graduate researcher Sarah Guerin. "We used computer models to predict the electrical response of a wide range of crystals and the glycine number was off the charts. We then grew long, narrow crystals of glycine in alcohol, and we produced electricity just by tapping them."

By using the computer models, the team is able to rely on predictive data to determine the best size and shape for these crystals to produce electricity, which could save years of trial and error lab work. They also have a patent pending for the technology, with a view to applying it to biodegradable power systems, devices that detect diseases inside the body and physiologically controlled drug pumps.

The research was published in the journal Nature.