Novel breath sensor for cystic fibrosis

A major issue with detecting acetonitrile, a compound characteristic of CF when found in exhaled breath, is that its concentration in exhaled breath is of the order of 10 ppb (parts per billion). Moreover, other components in breath such as water vapour and carbon dioxide affect the sensitivity of LAS.

Scientific advancement has made it possible to accurately detect components in breath through sensitive and selective analytical techniques. The MEDIXHALE (Medical diagnostics based on exhaled-air analysis with laser absorption spectroscopy) project developed an LAS sensor for acetonitrile.

Researchers worked to overcome issues with interference by using a small spectral region based on the infrared absorption spectra of acetonitrile and other components in breath. Another factor they worked on is increasing the absorption path length to get measurable signals. As a result, they built and characterised a cavity-enhanced absorption spectrometer. This device has an optical resonator with an effective path length of 7.3 km. This system manages up to four measurements per day.

To improve sensitivity and improve the detection of acetonitrile, researchers came up with a preconcentration stage using a carbon molecular sieve for acetonitrile absorption. They successfully managed to improve the limit of detection from 114 ppb to around 4 ppb. These results were confirmed through breath samples from healthy adults.

MEDIXHALE has successfully demonstrated proof-of-principle for quantitative measurements of acetonitrile in human breath. Future work prior to a clinical trial would need to focus on improving precision and throughput of this device. Demonstration of utility for non-invasive CF detection would significantly improve CF patient treatment and monitoring.