CNT-DNA sensors

The IDTechEx conference was held in Santa Clara, CA November 18 and 19, 2015, covering a wide range of topics including wearable devices and related technology such as sensors, printed electronics, and energy harvesting. This is one of the many items of interest from that conference.

Chemical sensors have the potential to perform countless missions for wearable Health Tech applications, from detecting toxins in the environment to identifying biomarkers in the wearer’s body. In order to be most useful, they must be tiny, affordable, and extremely accurate.

A new technology from Raymor NanoIntegris addresses these needs. Their researchers have developed ways to use carbon nanotubes (CNT) as detectors. They mount them on a silicon backplane, and use gold contacts at each end to provide an electrical connection. They then coat the nanotubes to make them sensitive to specific materials. For example, they can wrap a CNT with single strands of DNA designed to bind with the target substance. If the substance is present in the sensor’s location, the electrical characteristics of the CNT sensor will change, and this change can be measured to detect the presence of the material. Other techniques involve coating the CNTs with other materials such as polymers or metals.

The company has developed working sensors for a variety of substances, including ammonia, glucose, ethylene (“banana gas”), and other gases. A single device can have sensors for many different substances; one array made for NASA detects NO2, NH3, CH4, Cl2, HCl, toluene, benzene, acetone, formaldehyde and nitrotoluene all at the same time, all on a tiny integrated chip. The CNT sensors are extremely sensitive, detecting levels below 50 parts per billion. Unlike many other sensor technologies, these can also “reset” quickly, ready to respond in less than a second. This ability to create tiny, custom-designed sensors for different functions will make a wide range of new wearable Health Tech devices possible.