It’s more a possibility at the moment than anything else but researchers at Concordia University in Montréal, Canada have found a way to make an enzyme behave more like a battery. From the April 19, 2012 news item on Nanowerk,
Concordia Associate Professor László Kálmán — along with his colleagues in the Department of Physics, graduate students Sasmit Deshmukh and Kai Tang — has been working with an enzyme found in bacteria that is crucial for capturing solar energy. Light induces a charge separation in the enzyme, causing one end to become negatively charged and the other positively charged, much like in a battery.
In nature, the energy created is used immediately, but Kálmán says that to store that electrical potential, he and his colleagues had to find a way to keep the enzyme in a charge-separated state for a longer period of time.
“We had to create a situation where the charges don’t want to or are not allowed to go back, and that’s what we did in this study,” he says.
Kálmán and his colleagues showed that by adding different molecules, they were able to alter the shape of the enzyme and, thus, extend the lifespan of its electrical potential.
In the April 17, 2012 news item written by Luciana Gravotta for Concordia University, Kálmán provides an explanation of why the researchers were changing the enzyme’s shape,
In its natural configuration, the enzyme is perfectly embedded in the cell’s outer layer, known as the lipid membrane. The enzyme’s structure allows it to quickly recombine the charges and recover from a charge-separated state.
However, when different lipid molecules make up the membrane, as in Kálmán’s experiments, there is a mismatch between the shape of the membrane and the enzyme embedded within it. Both the enzyme and the membrane end up changing their shapes to find a good fit. The changes make it more difficult for the enzyme to recombine the charges, thereby allowing the electrical potential to last much longer.
“What we’re doing is similar to placing a race car on snow-covered streets,” says Kálmán. The surrounding conditions prevent the race car from performing as it would on a racetrack, just like the different lipids prevent the enzyme from recombining the charges as efficiently as it does under normal circumstances.
Apparently the researchers are hoping to eventually create biocompatible batteries with enzymes and other biological molecules replacing traditional batteries that contain toxic metals.