Breath Test Spots Diabetes

With tens of millions of individuals in the US alone living with diabetes, it is a major health concern. These people are at risk for some very serious complications, with an elevated risk for conditions like heart disease, stroke, kidney disease, and even death. Fortunately, most of these more serious outcomes can be kept at bay through a proper treatment regimen. But it has been estimated that up to 20% of people living with diabetes are unaware that they have it, which prevents them from seeking medical care.

At present, diagnostic tests for diabetes require a trip to the doctor's office, and likely some lab work. The cost, fear of a blood draw, and inconvenience of other procedures are enough to make many people decline screening for the condition — especially those that have no idea they may have it. To catch people that are not being served by existing technologies, we urgently need a low-cost and noninvasive way to test for diabetes and prediabetes.

Just breathe

This void could be filled by a new diagnostic tool that has just been described by a group led by researchers at The Pennsylvania State University and Hebei University of Technology. They have developed a small sensor that can accurately diagnose both diabetes and prediabetes. To use it, one only needs to breathe on it.

Unlike traditional tests that analyze glucose in the blood or in sweat, this device detects acetone in the breath. Acetone is produced naturally in the body as fat is broken down, and while everyone exhales some amount of it, concentrations above about 1.8 parts per million have been linked to the presence of diabetes. By focusing on this biomarker, the team created a method that avoids the need for invasive blood draws or complicated lab work.

The sensor is made of a material called laser-induced graphene (LIG). Created by exposing polyimide film to a carbon dioxide laser, the process “toasts” the material into a porous, few-layered graphene structure that is highly permeable to gases. This porous nature increases the chances of capturing acetone molecules from breath. However, LIG alone is not selective enough, so the researchers combined it with zinc oxide. Together, these materials form a junction that allows for highly specific detection of acetone while ignoring other gases.

One challenge the team faced was the high humidity of human breath. Water molecules can interfere with the sensor by competing with acetone for binding sites. To overcome this, the researchers added a molecular sieve membrane that blocks water vapor while allowing acetone to pass through. As a result, the device can function reliably even in humid conditions.

Problem solved?

In a series of tests, it was found that the sensor can detect acetone at concentrations as low as 4 parts per billion, with a rapid response and recovery time of just over 20 seconds. Because of this sensitivity, it was able to clearly distinguish between the breath of diabetic patients and healthy individuals, making it a promising tool for early diagnosis.

Currently, the prototype requires that patients exhale into a bag before the sample is tested, to minimize interference from ambient air. The researchers hope to refine the design in the near future so it can eventually be used under the nose or integrated into a face mask for continuous monitoring.