Breath Sensor

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Flexible polymer-based sensors offer a non-invasive and cost-effective alternative to traditional diagnostic procedures like biopsies or blood tests. These sensors are easy to use and can be worn on or near the skin. One class of these sensors, breath sensors, stand out for their ability to detect volatile organic compounds (VOCs) in human breath, which serve as biomarkers for conditions like diabetes and chronic obstructive pulmonary disease (COPD). Plasma treatment plays an important role in prototyping these sensors, ensuring optimal surface properties for reliable performance.

Researchers recently used Harrick Plasma’s equipment to develop a 3D printed breath sensor to detect kidney disease. This sensor specifically identifies trace amounts of ammonia (NH3), a key indicator of kidney dysfunction. The ammonia sensor consisted of carbon black electrodes 3D printed onto polyethylene terephthalate (PET) sheets. The PET sheets were then plasma treated in Harrick Plasma’s High Power Expanded Plasma Cleaner to increase their hydrophilicity. This process removed contaminants and ensured a subsequent smooth coating of the sensor’s active layer, the hydrogel poly(2-acrylamido-2methyl-1-propanesulfonic acid) [PAMPSA].

The ammonia gas sensor had a detection limit of 30 ppb and could distinguish between breath from a healthy person (0.05 – 1.5 ppm exhaled NH₃) and from a person with kidney disease (1.5 – 15 ppm). These results were reproduceable even after long-term storage of the sensors (up to 50 days).

By leveraging plasma treatment in sensor fabrication, researchers are developing reliable, high-performance diagnostic tools that pave the way for improved disease monitoring and early detection.