Breathalyzer Will Someday Detect Diseases

There is a new breathalyzer-like system that could one day detect illnesses by spotting biological markers in the air we exhale, researchers report.

The hope is that this could simplify medical diagnoses by making health monitoring as simple as breathing into a device, the scientists say. Their prototype device, called the airborne biomarker localization engine (ABLE), condensates airborne molecules into concentrated liquid droplets.

The droplets ABLE generates are compatible with existing tech, including simple test strips, making the "platform both highly accessible and very low-cost," study co-author Bozhi Tian, a professor at the University of Chicago, told Live Science in an email. The scientists described ABLE in a report published 21 May in the journal Nature Chemical Engineering.

"As a researcher working on biosensing and bioelectronics, I am very excited to see this work," said Jinghua Li, an associate professor in the Department of Materials Science and Engineering at The Ohio State University, who was not involved in the study.

"Airborne biomarker detection has long attracted significant interest, though achieving the required sensitivity has remained a challenge," Li told Live Science in an email. Once the technology is validated, "users could simply exhale onto a test strip and receive a health assessment within minutes in the future," she said.

Many diagnostic tests require blood draws, saliva swabs or urine samples — but collecting such samples can introduce risk, inconvenience, or both to patients. Sampling breath could help sidestep these problems.

The body emits volatile organic compounds (VOCs) — small organic molecules that are typically gaseous at room temperature — and these can be found in human breath. Studies suggest that specific chemicals can be tied to medical conditions, making them a potential tool for diagnosis. Several scientists recently compiled a database of 327 different breathborne VOCs that have also been tentatively linked to diseases, including asthma, diabetes and lung cancer.

However, there's a difficulty in using VOCs for diagnostics: they are present at incredibly low concentrations, sometimes numbering as few as 1 in a trillion particles of exhaled air. This makes monitoring these compounds challenging.

Now, ABLE can suck in exhaled air through a pump, add water vapor via a humidifier, and cool the mixture to cause condensation. This changes the airborne compounds into concentrated droplets that slide into a collection reservoir, ready for testing.

The prototype device measures 4 by 8 inches (10 by 20 centimeters) and costs less than US$ 200 to build, according to Tian. It can collect about 1 milliliter of condensate in 10 minutes, providing enough sample for existing liquid-detection methods to analyze.

As proof of concept, the researchers tested ABLE's ability to collect several airborne chemicals. One experiment looked for glucose in exhaled human breath, confirming that the samples were not too dilute and could be accurately tied to blood-sugar concentrations in the blood. "The high sensitivity of ABLE allows the usage of glucose test strips as the downstream sensors," the researchers reported.

The team also ran experiments with "humanized" lab mice imbued with microbes from human infants, who were born either preterm or full-term. They compared the concentrations of glycosphingolipids — known regulators of inflammation — in the breath of the two sets of mice, finding higher levels in the "preterm" group.