New smart mask tracks indicators of asthma, kidney disease through breath

The California Institute of Technology has developed a cutting-edge paper mask capable of real-time monitoring of chemicals in exhaled breath.

Interestingly, this mask can monitor various medical conditions, including respiratory issues like asthma, chronic obstructive pulmonary disease (COPD), and post-COVID-19 infections.

“Monitoring a patient’s breath is something that is routinely done, for example, to assess asthma and other respiratory conditions,” said Wei Gao, the lead investigator and professor of medical engineering.

“However, this has required the patient to visit a clinic for sample collection, followed by a waiting period for lab results.”

Gao and his team aimed to develop tools for remote personalized health monitoring that would provide real-time feedback in home or office settings. “For instance, we could use this information to assess how well a medical treatment may be working,” Gao added.

Cost-effective mask

This smart mask prototype is called EBCare (where EBC stands for exhaled breath condensate). As per the press release, the smart mask is designed to be cost-effective, with a material cost of around $1.

A key challenge in designing the mask was the necessity to cool and condense exhaled breath into a liquid state for chemical analysis. In clinical settings, this step is typically performed separately using ice or refrigerated coolers.

To address this challenge, the team incorporated a “passive cooling system.” They used hydrogel evaporative cooling and radiative cooling to efficiently chill the breath. This innovative approach enables real-time analysis of breath chemicals.

“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,” said Wenzheng Heng, lead author of the study and a graduate student at Caltech.

Furthermore, a series of bioinspired microfluidic channels swiftly transports the liquid to sensors for analysis once the breath has been converted into a liquid state.

Interestingly, the mask wirelessly sends the analysis results to a connected personal device, such as a phone, tablet, or computer.

Accurately detects biomarkers

The team evaluated the performance of masks, primarily focusing on patients with asthma or COPD. They monitored nitrite levels in the patient’s breath — a marker of inflammation in the airways. The results showed that the masks were effective in detecting this biomarker.

Moreover, the mask could accurately measure blood alcohol levels. This indicates mask potential for on-site use in checking for drunk driving situations.

The team also investigated the use of smart masks to monitor blood urea levels for kidney disease management.

When kidney function declines, protein metabolism waste products like urea build up in the blood. Simultaneously, urea levels in saliva increase, which can break down into ammonia gas, resulting in higher ammonium levels in exhaled breath.

As per the press release , the masks can accurately detect elevated ammonium levels in exhaled breath, which closely reflect blood urea levels. This could potentially be a valuable tool for monitoring kidney disease.

The team’s next goal is to expand this technology to incorporate different markers that can indicate various health conditions.

“This is a foundation for creating a mask that functions as a versatile general health–monitoring platform,” Gao concluded.

The findings were published in the journal Science .