Researchers in the US have found a way to generate energy using specially engineered viruses that convert movement into electricity.
The scientists from the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) claim their generator is the first to produce electricity by harnessing the piezoelectric properties of a biological material.
They say the breakthrough could increase the use of piezoelectric generators, which are typically made from inorganic materials that produce an electric current when pressure is applied but are made using toxic substances.
The research could also lead to a simpler way to make microelectronic devices because the viruses also arrange themselves into an orderly film that enables the generator to work.
‘More research is needed, but our work is a promising first step toward the development of personal power generators, actuators for use in nano-devices and other devices based on viral electronics,’ Berkeley Lab researcher Seung-Wuk Lee said in a statement.
To create the technology, the researchers first identified a virus that would be suitable for use in nanotechnology, choosing the M13 bacteriophage because it was easy to genetically engineer and benign to humans.
They applied an electrical field to a film of M13 viruses and found that the helical proteins that coat the viruses twisted and turned in response, indicating that it was piezoelectrical.
Next, the scientists increased the virus’s piezoelectric strength by adding four negatively charged amino acid residues to one end of the helical proteins, increasing the charge difference between the proteins’ positive and negative ends and boosting the voltage of the virus.
Then they created a system composed of 20 layers of the virus on top of each other to enhance the electrical properties. Set in the right conditions, the viruses spontaneously organised into a multilayered film about 1cm² in size.
This film was then sandwiched between two gold-plated electrodes, connected by wires to a liquid-crystal display.
When pressure is applied to the generator, it produces up to six nanoamperes of current and 400 millivolts of potential — about a quarter the voltage of an AAA battery.
‘We’re now working on ways to improve on this proof-of-principle demonstration,’ said Lee. ‘Because the tools of biotechnology enable the large-scale production of genetically modified viruses, piezoelectric materials based on viruses could offer a simple route to novel microelectronics in the future.’