A March 24, 2015 University of Illinois at Chicago news release (also on EurekAlert) describes the NERD, a Nano-Electro-Robotic Device which employs bacteria and graphene quantum dots,
As nanotechnology makes possible a world of machines too tiny to see, researchers are finding ways to combine living organisms with nonliving machinery to solve a variety of problems.
Like other first-generation bio-robots, the new nanobot engineered at the University of Illinois at Chicago [UIC] is a far cry from Robocop. It’s a robotic germ.
UIC researchers created an electromechanical device–a humidity sensor–on a bacterial spore. They call it NERD, for Nano-Electro-Robotic Device. …
“We’ve taken a spore from a bacteria, and put graphene quantum dots on its surface–and then attached two electrodes on either side of the spore,” said Vikas Berry, UIC associate professor of chemical engineering and principal investigator on the study.
“Then we change the humidity around the spore,” he said.
When the humidity drops, the spore shrinks as water is pushed out. As it shrinks, the quantum dots come closer together, increasing their conductivity, as measured by the electrodes.
“We get a very clean response–a very sharp change the moment we change humidity,” Berry said. The response was 10 times faster, he said, than a sensor made with the most advanced man-made water-absorbing polymers.
There was also better sensitivity in extreme low-pressure, low-humidity situations.
“We can go all the way down to a vacuum and see a response,” said Berry, which is important in applications where humidity must be kept low, for example, to prevent corrosion or food spoilage. “It’s also important in space applications, where any change in humidity could signal a leak,” he said.
Currently available sensors increase in sensitivity as humidity rises, Berry said. NERD’s sensitivity is actually higher at low humidity.
“This is a fascinating device,” Berry said. “Here we have a biological entity. We’ve made the sensor on the surface of these spores, with the spore a very active complement to this device. The biological complement is actually working towards responding to stimuli and providing information.”
Interesting, yes? Here’s a link to and a citation for the research paper,
Graphene Quantum Dots Interfaced with Single Bacterial Spore for Bio-Electromechanical Devices: A Graphene Cytobot by T. S. Sreeprasad, Phong Nguyen, Ahmed Alshogeathri, Luke Hibbeler, Fabian Martinez, Nolan McNeil, & Vikas Berry. Scientific Reports 5, Article number: 9138 doi:10.1038/srep09138 Published 16 March 2015
This paper is open access.
Dexter Johnson provides more context for this research in a March 26, 2015 post on his Nanoclast blog (on the IEEE [institute of Electrical and Electronics Engineers]) where he notes,
Recently, James Tours’ group at Rice University, who were the first to develop GQCs [graphene quantum dots] in 2013, created an improved way to manufacture them that promised to open them up to a new range of applications in optics.
Dexter’s insights make for worthwhile reading.