Regular grocery store white mushrooms could become future electricity generators, according to a new process.
The “bionic” button mushroom developed by the Stevens Institute of Technology supercharged the standard fungus with 3-D printed clusters of cyanobacteria. This cyanobacteria creates electricity while graphene nanoribbons pull together the current.
The work was published in a recent edition of the journal Nano Letters. The team hopes it could help improve our understanding of how biological energy could translate into creating electricity.
Transforming mushrooms to electrical generators
The entire project started thanks to the researchers' love of mushrooms.
"One day my friends and I went to lunch together and we ordered some mushrooms," said Sudeep Joshi, a postdoctoral researcher and author of the study.
"As we discussed them we realized they have a rich microbiota of their own, so we thought why not use the mushrooms as a support for the cyanobacteria. We thought let's merge them and see what happens."
From fields to sauteeing pans, button mushrooms are incredibly common. Even more common than the mushrooms are the cyanobacteria that can thrive on the mushrooms. Thanks to the mushroom's moisture, nutrients, and unique surface, the researchers discovered it could cultivate cyanobacteria there longer than any other common surface.
"In this case, our system -- this bionic mushroom -- produces electricity," said Manu Mannoor, an assistant professor of mechanical engineering at Stevens. "By integrating cyanobacteria that can produce electricity, with nanoscale materials capable of collecting the current, we were able to better access the unique properties of both, augment them, and create an entirely new functional bionic system."
Cyanobacteria is a popular study topic in bioengineering circles. However, previous research hasn't been able to keep cyanobacteria alive long enough on surfaces to tap into its full potential.
"The mushrooms essentially serve as a suitable environmental substrate with advanced functionality of nourishing the energy-producing cyanobacteria," said Joshi. "We showed for the first time that a hybrid system can incorporate an artificial collaboration, or engineered symbiosis, between two different microbiological kingdoms."
The pair used a 3D printer to create graphene nanoribbons that would cover the top of the mushroom. The graphene network served as a way to collect electricity from the cyanobacteria by acting like a "nano-probe," the researchers explained. It was like a needle sticking into the cyanobacteria cells to find its electrical signals, Mannoor said.
They then created a bio-ink with the cyanobacteria that sat atop the mushroom cap in a spiral pattern. At the places where the cyanobacteria connected with the graphene, the electron transfer would take place. The researchers put a light on the mushroom to spur photosynthesis in the cyanobacteria -- thus starting the photocurrent.
Joshi and Mannoor discovered they could produce more electricity depending on the density and alignment of the bacteria. The more densely packed the bacteria, the more energy it could produce.
Lighting the future
The work could one day help grow a non-traditional way to combat global climate change. While one button bionic mushroom won't make a massive dent, the team is currently working on a way to link them together to provide more power.
And it doesn't just stop with mushrooms. The cyanobacteria could play a massive role in powering other applications as a green solution.
"With this work, we can imagine enormous opportunities for next-generation bio-hybrid applications," Mannoor said. "For example, some bacteria can glow, while others sense toxins or produce fuel. By seamlessly integrating these microbes with nanomaterials, we could potentially realize many other amazing designer bio-hybrids for the environment, defense, healthcare, and many other fields."