Specialized Face Mask with Gas Sensor Detects Chronic Kidney Disease

The kidneys play a crucial role in removing waste products generated by the body’s metabolic processes. However, in chronic kidney disease (CKD), these organs become damaged over time and lose their function, which can lead to significant health complications. According to the U.S. Centers for Disease Control and Prevention, approximately 35 million Americans are affected by CKD, with many more potentially having the condition without being aware of it, especially in its early stages. Traditionally, the condition is diagnosed by analyzing metabolites in blood or urine. However, low-cost, simple diagnostic systems could simplify the process. Now, a modified surgical face mask designed to prevent the spread of airborne pathogens has shown potential to also detect health conditions, including CKD.

Chemical breath sensors are being explored as a diagnostic tool, as individuals with CKD often exhale higher levels of ammonia, a compound linked to the disease. However, ammonia is also present in several other health conditions. Researchers at the University of Rome Tor Vergata (Rome, Italy) aimed to develop a sensor that could detect ammonia along with other metabolites specifically related to CKD. To achieve this, they created a breath sensor integrated into the fabric of a face mask designed to detect metabolites associated with CKD. The process involved coating silver electrodes with a conductive polymer, commonly used in chemical sensors, and modifying the polymer with porphyrins—molecules that are sensitive to volatile compounds—thereby enhancing the sensor’s sensitivity. The electrodes were placed between the layers of a disposable medical face mask, with wires connecting the device to an electronic readout. When certain gases interacted with the modified polymer, they caused a measurable change in electrical resistance. Initial tests conducted in air confirmed the sensor’s high sensitivity to CKD-related metabolites, such as ammonia, ethanol, propanol, and acetone.

In early trials, the sensor accurately identified individuals with CKD most of the time. The masks were tested on 100 participants, with half diagnosed with CKD and the other half serving as a control group. The sensors detected various compounds in the participants' breath, and statistical analysis revealed a distinct pattern that differentiated those with CKD from the control group. The sensor successfully identified CKD in patients 84% of the time (true positive) and accurately ruled out the condition in 88% of patients without CKD (true negative). Furthermore, the results suggested that the sensor data could also help estimate the stage of CKD, which would be extremely valuable for diagnosis. The researchers believe these findings offer the potential for an easy, non-invasive, and cost-effective method of monitoring CKD patients.

“The implementation of this technology is expected to enhance the management of CKD patients by facilitating the timely identification of changes in disease progression,” said Sergio Bernardini and Annalisa Noce, coauthors of the study.