Breathprints: Each Time We Exhale We Leave Our Signatures

If you were one of the franchise loyalists who sat through Alien Resurrection (the 4th one) you may remember a subtle sci-fi flourish in which the commanding officer of a military spaceship breathes into a small key panel in order to unlock a door to the chamber where the aliens are kept. To the lay viewer, the breath-reader seems like a logical extension of the ubiquitous fingerprint ID pad. So why hasn't such technology come to fruition?

Because our breath chemistry changes depending on what we've been eating and drinking, how much sleep we got the night before, our overall health, and other variables, some experts have doubted the chemical consistency of our exhalations. But new research is generating new hope that, one day, we'll be able to diagnose illnesses and unlock doors to deadly alien monsters using only our "breathprints."

"Consistent with previous metabolomic studies based on urine, we conclude that individual signatures of breath composition exist," write a group of chemical researchers from Zurich in an article published this month in PLoS One. The x-factors of what you've recently eaten and such can cause some breath compounds to "vary relatively widely;" however, your breath has a "stable core" that is "highly donor-specific," the researchers say.

Not only do breathprints exist, but they're going to be critical to the development of personalized health care, the researchers say. Rather than pull blood, urine or tissue samples from you, physicians could simply ask you to blow into a special breathalyzer. (Imagine how much faster and less painful!) Present in your breath, apart from CO2, oxygen and other vapors, are metabolites—byproducts of the chemical processes that sustain our cells, a.k.a. our metabolism. Your metabolite profile is dictated in part by the cereal you ate this morning and the bourbon you drank the night before. It changes daily. So how can something so fickle be clinically useful?

The researchers argue–and their findings support the idea–that embedded in our every expired breaths, deeper than the bourbon residue, are chemical signatures unique to us. To test this they analyzed breath samples from 11 participants, four times a day, for nine days. Through a technique called mass spectrometry, the researchers were able to pick apart the biomolecules in each sample. An individual's samples varied at different times of day, as hypothesized, but not outside the unique spectrum of his or her personal profile.

Lead researcher Renalto Zenobi says commercial mass spectrometers can be modified to function as breathprinting devices. The catch seems to be that, in order for the breathprinting system to work effectively, we'd all need to hand over breath samples -- the same way you can be identified by your fingerprints only if they are already on record. But Zenobi is confident that the modified devices "will eventually find their way into clinics and doctor's offices."