The world of wearable health monitoring is advancing at a rapid pace. From watches to patches and various sensors, these devices are revolutionizing the way individuals manage their well-being. Now, joining this revolutionary lineup is a groundbreaking high-tech paper mask designed to monitor breath and improve respiratory health.
Wei Gao, a leading expert in medical engineering at Caltech, and his team have developed a cutting-edge smart mask prototype known as EBCare. Unlike other smart masks that focus on physical indicators such as temperature and humidity, EBCare goes a step further by analyzing the chemical composition of exhaled breath in real time.
This innovative technology can monitor a wide range of medical conditions, including respiratory ailments like asthma, COPD, and post-COVID-19 infections. For instance, it can track the levels of nitrite in the breath of asthma patients, providing valuable insights into airway inflammation.
The potential of this smart mask is enormous, offering a new level of personalized respiratory health monitoring that could significantly improve the lives of countless individuals. With its ability to provide real-time chemical analysis, EBCare has the power to reshape the way we approach respiratory health care.
“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,” says Gao, the lead investigator of a new study describing the mask in the journal Science. “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 groundbreaking work has led to the development of wearable biosensors capable of analyzing human sweat to measure a wide array of vital indicators, from metabolites and nutrients to hormones and protein levels. His latest focus? Monitoring breath is a task that presents a whole new set of challenges.
In order to selectively analyze the chemicals or molecules present in someone’s breath, researchers must first cool the breath vapor into a liquid. Traditionally, this cooling step was carried out separately from the analysis, using methods such as chilling moist breath samples on ice or using bulky refrigerated coolers.
Gao’s innovation lies in a self-cooling mask equipped with a passive cooling system that ingeniously integrates hydrogel evaporative cooling with radiative cooling. This sophisticated technology effectively chills the breath right on the face mask, setting a new standard for breath analysis and opening up a world of possibilities for non-invasive health monitoring.
“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,” says Wenzheng Heng, lead author of the study and a graduate student at Caltech. “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.”
Once the breath has been converted into a liquid, a series of capillaries, belonging to a class of devices referred to as bioinspired microfluidics, 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,” says Gao. “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 results showed that the masks accurately detected the biomarker, indicating inflammation in the patient’s airways.
In an additional investigation, the team showcased the masks’ high precision in detecting blood alcohol levels in human subjects. This suggests that the masks could serve as valuable tools for conducting on-the-spot drinking-and-driving checks and for monitoring alcohol consumption in various scenarios.
Moreover, the study delved into the potential use of the masks in assessing blood urea levels for the purpose of monitoring and managing kidney disease. As kidney function deteriorates, by-products of protein metabolism, such as urea, accumulate in the bloodstream.
Simultaneously, urea levels rise in saliva, breaking down into ammonia gas, leading to elevated ammonium levels in breath condensate. The research illustrated that the smart masks could impeccably detect these ammonium levels, serving as an accurate reflection of 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.”
Participants consistently reported positive experiences with the mask’s comfort, even individuals with breathing difficulties.
“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, investigator at the Lundquist Institute for Biomedical Innovation at Harbor-UCLA and professor of medicine at the David Geffen School of Medicine at UCLA. “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.”
Journal reference:
- Wenzheng Heng, Shukun Yin, Jihong Min, Canran Wang, Hong Han, Ehsan Shirzaei Sani, Jiahong Li, Yu Song, Harry B. Rossiter, Wei Gao. A smart mask for exhaled breath condensate harvesting and analysis. Science, 2024; DOI: 10.1126/science.adn6471