Scientists create 'bionic mushrooms' that can produce green power
Scientists, including those of Indian origin, have created a bionic device that generates green power by 3D-printing clusters of cyanobacteria on an ordinary white-button mushroom. The research, by Stevens Institute of Technology, US is part of an effort to improve our understanding of cells' biological machinery and how to use those intricate molecular gears to useful systems for defense, healthcare, and the environment.
Supercharging mushrooms with cyanobacteria, nanoribbons made it bionic
The researchers took an ordinary white-button mushroom from a grocery store and made it bionic, supercharging it with clusters of cyanobacteria that create electricity and swirls of graphene nanoribbons that can collect the current. "We were able to better access the unique properties of both (cyanobacteria and nanoribbons), augment them, and create a new functional bionic system," Manu Mannoor, an assistant professor at Stevens.
Can mushrooms provide right environment for cyanobacteria to produce electricity?
However, researchers haven't used cyanobacteria much in bio-engineered systems because it doesn't survive long on artificial bio-compatible surfaces. Mannoor and Sudeep Joshi, a postdoctoral fellow in his lab, wondered if white button mushrooms, which naturally host a rich microbiota but not cyanobacteria specifically, could provide the right environment- nutrients, moisture, pH and temperature- for the cyanobacteria to produce electricity for a longer period.
Mushrooms essentially serve as a suitable environmental substrate
The researchers showed that the cyanobacterial cells lasted several days longer when placed on the cap of a white-button mushroom versus a silicone and dead mushroom as suitable controls. Joshi said the mushrooms essentially serve as a suitable environmental substrate. "We showed for the first time that a hybrid system can incorporate an artificial collaboration between the two different microbiological kingdoms," he added.
Researchers used 3D printer to print graphene nanoribbons
Researchers used a robotic arm-based 3D printer to first print an "electronic ink" containing the graphene nanoribbons. This printed branched network served as an electricity-collecting network atop the cap of the mushroom by acting like a nano-probe - to access bio-electrons generated inside the cyanobacterial cells. Imagine needles sticking into a single cell to access electrical signals inside it, said Mannoor.
Researchers printed bio-ink containing cyanobacteria onto mushroom's cap
Next, they printed a "bio-ink" containing cyanobacteria onto the mushroom's cap in a spiral pattern intersecting with the electronic ink at multiple contact points. At these locations, electrons could transfer through the outer membranes of the cyanobacteria to the conductive network of graphene nanoribbons.
Shining light on mushrooms activated cyanobacterial photosynthesis
Shining a light on the mushrooms activated cyanobacterial photosynthesis, generating a photocurrent. In addition to the cyanobacteria living longer in a state of engineered symbiosis, researchers showed that the amount of electricity these bacteria produce can vary depending on the density and alignment with which they are packed, such that the more densely packed together they are, the more electricity they produce.
'Enormous opportunities for next-generation bio-hybrid applications'
With 3D printing, it was possible to assemble cyanobacterial cells so as to boost their electricity-producing activity eight-fold more than the casted cyanobacteria using a laboratory-pipette. "With this work, we can imagine enormous opportunities for next-generation bio-hybrid applications. By seamlessly integrating these microbes with nanomaterials, we could potentially realize many other amazing designer bio-hybrids for the environment, defense, healthcare, and other fields," Mannoor said.
