Oct. 21, 2021 -- Most people think of alcohol level testers, commonly called Breathalyzers, as tools for measuring alcohol when someone exhales. But scientists have taken the technology well beyond DUI checkpoints, aiming it instead at detecting diseases.
The breath of someone who is sick often has a chemical profile that is specific to their health condition. Methane in a person’s exhalations, for example, could signal an intestinal issue. If these chemical profiles can be matched to specific illnesses, then these testing devices could become handy screening tools for some conditions.
But existing devices typically detect only a single compound, with results taking 10 minutes or more, leading to a quest for faster devices that can identify more chemicals at the same time. Researchers have turned to a tool called a frequency comb to solve this problem.
This tool, first developed in 2008, pings breath samples with laser pulses in distinct frequency ranges of the light spectrum, separated like the teeth of a comb. Every mini-cloud of droplets we exhale contains over 1,000 compounds. When researchers send the pulses through these exhaled droplets, each chemical absorbs the light in its own specific pattern, creating a light "signature."
In a study published in the Proceedings of the National Academy of Sciences, investigators report that an updated version of the frequency comb can detect at least four and possibly up to 10 compounds linked to a health condition. In addition to accurately sorting out methane, methanol, and two chemical forms of water in breath, the combs also might be able to identify formaldehyde and ammonia, among others.
Before frequency combs become common in the clinic, though, a few steps remain. Scientists must link chemical profiles to specific diseases and find a way to make a compact version of the combs. If all goes well, the result could be a device capable of rapid, inexpensive screening for some diseases, with no need for lab testing, which would be especially welcome where testing facilities are scarce.