The EBCare mask can analyze the chemicals in one’s breath in real time (Photo – Caltech/Wei Gao and Wenzheng Heng)
A new type of wearable device, a high-tech paper mask, can monitor heart activity, and inflammation levels in one’s breath.
By Whitney Clavin, Caltech
Personalized wearable devices that monitor people’s health are on the rise. From watches to patches and other types of sensors, these smart devices can monitor heart activity, and inflammation levels to help patients manage their health from their own homes.
Caltech’s Wei Gao, professor of medical engineering, and his colleagues have developed a prototype for a smart mask that can be used to monitor a range of medical conditions, including respiratory ailments, such as asthma, COPD (chronic obstructive pulmonary disease), and post-COVID-19 infections. Other smart masks monitor physical changes like the temperature, humidity, or rate of breathing. This one, called EBCare, can analyze the chemicals in one’s breath in real time. For example, the mask could monitor asthma patients for levels of nitrite, a chemical that indicates airway inflammation.
“EBC” is an acronym used in this field that means “exhaled breath condensate.” To analyze the chemicals or molecules in someone’s breath, the breath vapor must be cooled into a liquid. In clinical settings, moist breath samples are chilled on buckets of ice or in bulky refrigerated coolers. The new mask, in contrast, is self-cooling. The breath is cooled by a passive cooling system that integrates hydrogel evaporative cooling with radiative cooling to effectively chill the breath on face masks.
Once the breath has been converted into a liquid, a series of capillaries immediately transports the liquid to sensors for analysis. “We learned from plants how to transport the water,” says Gao. “Plants use capillary forces to draw water upward from the ground.”
The results of the analysis are then transmitted wirelessly to a personal phone, tablet, or computer. “The smart mask can be prepared at a relatively low cost. It is designed to cost only about $1 in materials.”
To test the masks, the team performed a set of human studies, primarily focused on patients with asthma or COPD. They specifically monitored the patients’ breath for nitrite, a biomarker for inflammation in both conditions. The masks accurately detected the nitrite, indicting when inflammation occurred in the patients’ airways.
This cross-section of the smart mask shows the different layers that make it work (Photo – Caltech/Wei Gao and Wenzheng Heng)
In another study, the team demonstrated that the masks accurately detected blood alcohol levels in human subjects, suggesting the masks could be used for on-site drinking-and-driving checks or other forms of alcohol-consumption monitoring.
They also looked at how the masks could potentially be used in the monitoring and management of kidney disease. As kidney function declines higher ammonium levels in the breath condensate. The new study showed that the smart masks could accurately detect these ammonium levels, closely reflecting urea levels in the blood.
“These first studies are a proof of concept,” says 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.”
As for the comfort of the masks, participants reported favorable experiences, even those with breathing problems.
“The smart mask platform for EBC harvesting and analysis represents a major advance in the potential to monitor lung health in real time,” says co-author Harry Rossiter. “That concept, that biosensors for a wide range of compounds may be added in the future, highlights the game-changing potential of the smart mask for health monitoring and diagnostics.”
The study titled “A smart mask for exhaled breath condensate harvesting and analysis” was funded by the National Institutes of Health, the National Science Foundation, the Tobacco Related Disease Research Program, and the U.S. Army Medical Research Acquisition Activity.
It was developed by Wei Gao, professor of medical engineering, and his colleagues. Wenzheng Heng, lead author of the study, is a graduate student at Caltech. Co-author Harry Rossiter, investigator at the Lundquist Institute for Biomedical Innovation at Harbor-UCLA and professor of medicine at the David Geffen School of Medicine at UCLA. Caltech authors include graduate students Shukun (Kevin) Yin, Canran Wang, Hong Han, and Jiahong Li; postdoc Jihong Min; with Ehsan Shirzaei Sani and Yu Song, former postdocs at Caltech.
This article has been edited for clarity and brevity.
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