Cyborg Beetles Detect Nerve Gas

Images: UNIST/American Chemical Society

The rival rock stars of nanotech—carbon nanotubes and graphene—have joined forces to become a super group of late. They are now being combined to make supercapacitors or just to make the manufacturing process for one of them less arduous.

Now researchers in South Korea have joined them together to create one monolithically integrated flexible electronic device that can be synthesized in a single step and be attached to, among other things, live stag beetles that can be set loose to detect a range of environmental conditions or nerve gas agents.

In research, which was published in the journal Nano Letters (“In-situ Synthesis of Carbon Nanotube-Graphite Electronic Devices and Their Integrations onto Surfaces of Live Plants and Insects"), the Korean team developed a method using multiple catalysts to synthesize the all-carbon electronic devices so that they include transistors, electrodes, interconnects, and sensors all together that can fit onto a human fingernail or the back of a beetle.

The design of the device takes advantage of carbon nanotubes semiconducting properties so that they serve as the transistors or the sensors, while the pure conductor properties of graphene allows it to serve as the material for the interconnects.

"The channel part requires semiconducting materials whose resistance can be sensitively controlled by external bias,” explained Jang-Ung Park, Assistant Professor at Ulsan National Institute of Science and Technology (UNIST), in an interview for Phys.org. “The electrode part needs metallic materials whose resistance is very small with the negligible change by external bias."

The Korean researchers, representing both the UNIST and the Korea Electrotechnology Research Institute, have demonstrated that the fully integrated, all-carbon devices can be attached to a wide variety of surfaces including plants, insects, paper, clothes, and human skin. The flexible electronic sensors remain attached to the surfaces by exploiting van der Waal forces, which represent all the attractive or repulsive forces between molecules that are not covalent bonds.

The researchers took the unusual step of applying the flexible sensors to plants and insects to see if the devices could be used to detect very low levels of DMMP vapor (1 ppm), which is used for producing nerve agents such as soma and sarin. Park told Nanoclast that his team's devices performed comparably to current state-of-the-art sensors and showed that the sensors could be used to monitor a variety of environmental conditions, including temperature, humidity, pollution, and infections. The devices do not need a battery because the researchers have integrated an antenna onto the devices that can be used to deliver power to them.

“We integrated antennas with our devices," Park said. "Thus, the wireless transportation of power and sensing signals was possible with no battery."

While the researchers initially have just demonstrated that the all-carbon flexible sensors can be used as environmental sensors, they intend to look at how the technology can be adapted for implantable and wearable devices.

“In this paper, we just demonstrated the detection of the nerve gas using the biocompatible devices," Park said. "As our future research, we will develop various sensing systems, including diabetes, pollutions and radioactivity, using the wearable electronic devices."

Images: UNIST/American Chemical Society

Advertisement

Nanoclast

IEEE Spectrum’s nanotechnology blog, featuring news and analysis about the development, applications, and future of science and technology at the nanoscale.

 
Editor
Dexter Johnson
Madrid, Spain
 
Contributor
Rachel Courtland
Associate Editor, IEEE Spectrum
New York, NY
 
Robotics

Moth Pupa + MEMS Chip = Remote Controlled Cyborg Insect

MEMS08_BTI01.jpg PHOTO: Boyce Thompson Institute Take a moth during its pupal stage. Insert electrodes and a control chip into it. Wait a few days. The result? An unmanned aerial vehicle, of course! Turning moths (or pigeons, rats, beetles, bees, and sharks, for that matter) into remote controlled cyborg critters has long been a goal of mad scientists and DARPA program managers. Spectrum's Sally Adee reports on the latest initiatives of DARPA's HI-MEMS, or Hybrid Insect Micro-Electro-Mechanical Systems project. (I guess the name says it all.)…

 
Semiconductors

Nanomaterials Turning Us into Cyborgs? Whatever Next?

I have to confess one of my favorite past times is reading a mainstream journalist mangling a story on nanotechnology. But in this example the journalist did a yeomanâ''s job only messing up the requisite definition slightly â''used to develop materials that are 100 nanometers or smallerâ''. Yeah, almost right, I think if you add the idea of materials with features below 100 nanometers it wouldnâ''t have sounded so odd to me. Who really sounded odd to me was the nanotechnology expert who was visiting the beat reporterâ''s hometown, Akhlesh Lakhtakia. Lakhatia, a professor with the Department of Engineering Science and …

Advertisement