Biomarkers in exhaled breath continue to be intriguing targets for detecting and monitoring of a variety of health conditions. Due to their low concentrations and the difficulty of developing sensors, there’s still a lot of untapped potential for breath analysis. To speed this process along, researchers at Fujitsu have developed a sensor that can accurately measure ammonia in exhaled breath, down to 10 parts per billion, a marker that can point to signs of liver disease and the ulcer-causing H. pylori bacterial infection. Additionally, the researchers developed a modified device able of measuring nonanal, a potential biomarker for lung cancer.
The researchers plan on expanding the capability of the sensor platform to detect a lot of other, still not properly researched, compounds that we exhale.
Here are some details about the technology according to Fujitsu:
Copper ions in copper(I) bromide, a P-type semiconductor, undergo a reversible adsorption with ammonia molecules. Making use of this property, Fujitsu Laboratories developed a sensor in which the film thickness and copper(I) bromide composition were optimized for use as a breath sensor. Because electron supply from the ammonia reduces the carriers in the film, this has the effect of increasing electrical resistance between electrodes. This phenomenon was used and the reactions quantified. As a result, with a sensitivity differential of 2,500 times that for acetone, another gas commonly found in the breath, the sensor was able to distinguish and measure just ammonia from a level of 10 parts per billion (ppb).