NASA is ready to begin testing the E-Nose COVID-19 screening device prototype developed by subcontractor Variable Inc., of Chattanooga, Tenn. NASA received $3.8 million from the Department of Health and Human Services to enhance E-Nose, which was originally developed to measure air quality inside spacecraft. The updated version is intended to facilitate screening for SARS-CoV-2 by "sniffing out" the signature volatile organic compounds (VOCs) in the breath of infected individuals.

It took Variable six months to develop the electronics and packaging for the smartphone-based device as well as Bluetooth functionality and a paired mobile app that processes, displays and transmits sensor data. The company drew on its experience in developing the sensor technologies for devices that detect temperatures and complex gases as well as other components.

The company’s Founder and CEO, George Yu, previously worked with NASA on a contract for the Department of Homeland Security. That device enabled smartphones “to detect toxic gases used in acts of terrorism,” Yu told BioWorld. The DHS device and E-Nose both integrate nanosensor technology invented by NASA scientist Jing Li at the space agency’s Ames Research Center in California.

Using optimized versions of the same technology enabled rapid development of the new application. “It’s because of that intimate knowledge and background that Variable was able to help NASA produce a prototype in a short time frame,” Yu added. To adapt to the COVID-19 situation, the sensors “needed to scaled and packaged in a way that could be easily accessible in both a clinical and home setting.”

As a result of the retooling, the pandemic version of the electronic nose is a hand-held device, unlike most of the bulky instruments used to detect harmful gases or VOCs. The lightweight and compact product is readily portable, making it suitable for a wide variety of environments. In many situations, it could replace the temperature checks often used now, which occur in less than 5% of infected individuals during the period in which they are most contagious.

Testing underway

While Variable has completed its part in the project, NASA is now refining the sensors to better detect the target VOCs. The prototype design allows the sensor chips to be swapped out as the development team learns more about the VOCs associated with COVID-19.

The E-Nose employs a large array of different nanosensors, which gives it built-in flexibility. “Each sensor responds to the chemicals in breath differently. This allows scientists to map patterns associated with different diseases. Through clinical testing, the hope is to find the COVID-19 virus pattern.”

The NASA team is working with researchers at Johns Hopkins University and the Lawrence Livermore National Lab to home in on the VOCs characteristic of SARS-CoV-2 infections. Once they have identified the virus’s biosignature, they will modify the sensors to distinguish it from breath readings of healthy individuals and people with other types of infection, followed by field testing and clinical trials.

"Once the clinical trials are completed and the sensitivity and specificity are demonstrated, E-Nose can be deployed in factories, airports, grocery stores, and businesses of all sorts to rapidly screen for active infections," said Li. "It's a noninvasive and rapid way to keep our communities safe as this pandemic continues."

Ultimately, data from the E-Nose would be incorporated with body temperature and other symptoms and analyzed by NASA’s advanced machine learning programs for a more accurate and virtually immediate determination of infection. The space agency is currently working on the algorithm that would underlie COVID-19 detection with the E-Nose.

Because of its interchangeable structure and large number of sensors, “E-Nose can be used as a platform for other medical conditions as well as meeting its original goal of monitoring astronaut health and crew cabin air quality," said Rupak Biswas, director of the Exploration Technology Directorate at Ames. "With the potential for other applications in the space and Earth sciences, E-Nose is a noninvasive, rapid technology solution that can meet the current COVID-19 crisis and support NASA's future exploration and research."