A team of engineers at the California Institute of Technology (Caltech) say they have developed a smart mask that can be worn to monitor a range of medical conditions, including respiratory ailments, asthma, COPD, and post-COVID conditions, and can even show whether a treatment is having the desired effect. The mask differs from others being developed that monitor temperature, humidity, or breathing rate and instead monitors the chemicals in one’s breath in real time.
The new prototype mask analyzes what is called “exhaled breath condensate”—or EBC—to detect chemical biomarkers indicative of specific conditions, the researchers report in the journal Science. As an example, they say it can monitor a person’s nitrite levels, a chemical biomarker that is indicative of respiratory inflammation.
“Monitoring a patient’s breath is something that is routinely done, for example, to assess asthma and other respiratory conditions. However, this has required the patient to visit a clinic for sample collection, followed by a waiting period for lab results,” explained lead investigator Wei Gao, PhD, a professor of medical engineering. “Since COVID-19, people are wearing masks more. We can leverage this increased mask use for remote personalized monitoring to get real-time feedback about our own health in our home or office. For instance, we could use this information to assess how well a medical treatment may be working.”
Gao’s team at Caltech specializes in the development of wearable biosensors. His lab has also developed wearable technology that can analyze the metabolites, nutrients, hormones, and protein levels found in human sweat.
For the latest development, the team had to devise a method for a wearable method that can analyze chemicals or identify molecules in a patient’s breath. In a clinical setting this is typically achieved by cooling the breath to condense it to liquid form which can then be tested and analyzed. For the new mask, Gao and team developed a passive cooling system for the mask that combines the evaporative cooling of hydrogel with radiative cooling to chill the breath.
Once the breath has been condensed to liquid form, a series of microfluidic capillaries in the mask carries the liquid to onboard sensors for analysis. Results of these analyses are wirelessly transmitted to a smartphone, tablet, or computer.
“The mask represents a new paradigm for respiratory and metabolic disease management and precise medicine because we can easily get breath specimens and analyze the chemical molecules in breath in real time through daily masks,” said Wenzheng Heng, lead author of the study and a Caltech graduate student. “The breath condensate contains soluble gases as well as nonvolatile substances in the form of aerosols or droplets, such as metabolic substances, inflammatory indicators, and pathogens.”
To test their prototype, the Caltech engineers, performed a series of human studies with patients that had either asthma or COPD, specifically focusing on detecting nitrite a biomarker of inflammation common to both conditions. The mask performed as intended, accurately identifying the biomarker.
The team also showed that the mask—which they say is designed to cost only $1 in materials for each—also accurately measured blood alcohol levels, indication that it also has the potential be used for law enforcement for drunk driving tests. An additional test looked to evaluate blood urea levels which could help monitor patients with kidney disease.
“These first studies are a proof of concept,” noted Gao. “We want to expand this technology to incorporate different markers related to various health conditions. This is a foundation for creating a mask that functions as a versatile general health–monitoring platform.”
