Thin films of viruses can generate an electrical charge when subjected to mechanical stress — a form of energy conversion known as the piezoelectric effect.

Seung-Wuk Lee and his team at the Lawrence Berkeley National Laboratory, California, measured the charge generated by stressing self-assembled films of M13 bacteriophage, a virus that attacks only bacteria. The authors boosted the films' power output by modifying the proteins that form the phage outer coat and by stacking the films on top of each other. The team went on to build a penny-sized generator containing the films, which produced enough power to light up a liquid-crystal display.

The viral power generator could be used as an environmentally friendly component in nanodevices, the authors suggest.

Nature Nanotechnol. http://dx.doi.org/10.1038/nnano.2012.69 (2012)