The bio-robot goes under the less-than-flattering acronym of NERD. This stands for “Nano-Electro-Robotic Device.” Essentially the device is a bacterial spore. To the spore, scientists have affixed graphene quantum dots.
Graphene is a fascinating material. Consisting of a single layer of carbon atoms arranged in a honeycomb lattice, the material is extremely stable, flexible, highly conductive, and of particular interest for electronic applications.
To the graphene dots, two miro-electrodes have been attached. The electrodes are used to alter the humidity levels around the spore. If the humidity is programmed to fall, then the spore shrinks. This is due to water being propelled outwards. The shrinking process causes the quantum dots move closer together. This increases the conductivity.
The response is very fast and up to ten times faster than would be achieved using an artificial sensor created from human-made water-absorbing polymers. The sensitivity was tested under high pressure and low-humidity conditions, and the fast response times were replicated.
The range of tests indicates that the new sensor could be used under low humidity conditions, which would include areas where food is held. Here, if the humidity was rising – something which would affect food quality – an alarm could sound. Also, if food was designed to be vacuum packed and the vacuum was breached, allowing the ingress of air, then a similar alarm would sounds.
If the tests can be replicated on a larger scale, then the researchers may have created a fast and effective water-proof, environmentally tough sensor that can be used to assess food safety.
The bio-robots were developed at the University of Illinois at Chicago. The findings have been published in the journal Scientific Reports. The research is titled “Graphene Quantum Dots Interfaced with Single Bacterial Spore for Bio-Electromechanical Devices: A Graphene Cytobot.”
