Single-Walled Carbon Nanotubes Monitor Blood Glucose in Vivo

University of Illinois researchers led by Michael S. Strano have fabricated a glucose sensor out of single-walled carbon nanotubes. The technology could prove a blessing to diabetics and others who need to pay close attention to their blood chemistry.

Carbon nanotubes were a logical choice for the sensor because they characteristically fluoresce in the NIR spectral region, where human tissue and biological fluids are particularly transparent. The tubes are first suspended in water and then coated with a monolayer of glucose oxidase, an enzyme that prevents the tubes from cohering to one another and also forms a selective site on which glucose can bind and generate hydrogen peroxide. The tubes are then exposed to ferricyanide, an ion sensitive to hydrogen peroxide, which passes through the porous monolayer and attaches to the tube surface. In the presence of glucose, the glucose oxidase produces hydrogen peroxide that quickly reacts with the ferricyanide. The resulting changes in the nanotubes' electron density and optical properties affect their fluorescent qualities—the more glucose, the greater the fluorescence.

 Single-walled carbon nanotubes were encased in a permeable capillary for insertion into the body.
Single-walled carbon nanotubes were encased in a permeable capillary for insertion into the body.

To demonstrate the practicality of using the treated nanotubes as biomedical indicators, the investigators secured some of them in a capillary permeable to glucose and inserted it into human tissue. The sensor's fluorescent behavior corresponded to the local glucose concentration.


Sensors 2019 Hits Silicon Valley June 25-27!

Join 7,000+ engineers this June in San Jose at the sensor industry’s biggest event! With 65+ Technical Sessions, 100+ Leading Speakers, 10 new and updated tracks, and 300+ Interactive Exhibits, there’s more opportunity than ever to connect with this booming industry and the technologies driving it. See thousands of the newest technologies in action, learn about the latest applications, and develop invaluable partnerships at the only event dedicated to sensors, connectivity, and systems.

According to Strano, the new surface chemistry technique permits electrons to be moved into and out of the nanotubes without damaging their structural bonds. And the sensor could be adapted to respond to other analytes, permitting it to detect a wide range of chemical components in blood and tissue.

Short Takes
Short Takes

The research team also included Seunghyun Baik, Paul Barone, and Daniel Heller. The work was supported by the National Science Foundation.

Contact Dr. Michael S. Strano, University of Illinois at Urbana-Champaign, Urbana, IL; 271-333-3634, [email protected],

Suggested Articles

The expansion comes just a week before U.S. president Donald Trump is planned to meet with China’s president Xi Jinping to talk trade.

Global Smart Space Market: Technologies and Applications

Far Infrared (FIR) technology that can deliver a complete autonomous-vehicle sensing solution.