In their latest sample of technology, researchers at the Stevens Institute of Technology have taken an ordinary white bud-shaped mushroom from a supermarket and made it bionic by driving them with 3-D-printed clusters of cyanobacteria that generate electricity and swirls of graphene nanoribbons that can collect the power.
The work, reported in the November 7 issue of Nano Letters, may sound like something straight out of Alice in Wonderland, but the hybrids are part of a broader effort to better improve our understanding of cell biological cells and how those complex molecular gears and levers can be used to create new technologies and useful systems for defense to fabricate. healthcare and the environment.
"In this case, our system, this bionic mushroom, produces electricity," says Manu Mannoor, an assistant professor in mechanical engineering at Stevens. "Through the integration of cyanobacteria that can produce electricity, with nanoscale materials capable of collecting the flow, we have gained better access to the unique properties of both, they have expanded and created a completely new functional bionic system."
The ability of cobactants to produce electricity is well known in biotechnological circles. However, researchers are limited in the use of these microbes in biotechnological systems because cyanobacteria do not survive long on artificial biocompatible surfaces. Mannoor and Sudeep Joshi, a postdoctoral researcher in his lab, wondered whether white button mushrooms, which naturally contain a rich microbiota but not specifically cyanobacteria, could provide the right environmental nutrients, moisture, pH and temperature – for the cyanobacteria to generate electricity. produce for a longer period.
Mannoor and Joshi showed that the cyanobacteria cells lasted several days longer if they were placed on the cap of a white mushroom than a silicone and dead mushroom as suitable controls. "The mushrooms serve essentially as a suitable substrate for the environment with advanced functionality for feeding the energy-producing cyanobacteria," says Joshi. "We have shown for the first time that a hybrid system can incorporate an artificial collaboration or engineered symbiosis between two different microbiological kingdoms."
Mannoor and Joshi used a robot-based 3D printer to first print an "electronic ink" containing the graphene nanotapes. This printed branched network serves as a network for collecting electricity on top of the cap of the mushroom by behaving as a nanosonde for access to bioelectrons generated in the cyanobacteria cells. Imagine that needles stick in a single cell to gain access to electrical signals in it, Mannoor explains.
Then they printed a "bio-ink" with cyanobacteria on the cap of the mushroom in a spiral pattern that cut through multiple electronic ink. At these locations electrons can be transferred through the outer membranes of the cyanobacteria to the conducting network of graphene nanoribbons. A light shines on the cyanobacterial photosynthesis activated by mushrooms, generating a photocurrent.
In addition to the cyanobacteria that lived longer in a state of engineered symbiosis, Mannoor and Joshi showed that the amount of electricity produced by these bacteria can vary depending on the density and alignment with which they are packaged, so that they are densely packed together, the more electricity they produce. With 3D printing, it was possible to compose them to increase their electricity producing activity eight times more than the cast cyanobacteria using a laboratory pipette.
Recently, some researchers have 3D-printed bacterial cells in different spatial geometrical patterns, but Mannoor and Joshi, as well as co-author Ellexis Cook, are not only the first to shape the pattern to increase their electricity generating behavior, they also integrate a to develop functional bionic architecture.
"With this work we can imagine enormous potential for the next generation of bio-hybrid applications," says Mannoor. "For example, some bacteria may glow, while others may feel toxins or produce fuel, and by integrating these microbes seamlessly with nanomaterials, we can achieve many other great bio-hybrids for the environment, defense, health care and many other areas."
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"Bacterial Nanobionics via 3D Printing" Nano Letters (2018). DOI: 10.1021 / acs.nanolett.8b02642