A Breath Test for Monitoring Glucose Levels

This e-nose can detect glucose levels with 90 percent accuracy

2 min read
illustration of open mouth

This article is part of our exclusive IEEE Journal Watch series in partnership with IEEE Xplore.

Diabetes is a very common condition affecting roughly 10 percent of the U.S. population—and, according to the World Health Organization, there are 422 million people living with diabetes around the world. To manage the disease, people must test their blood glucose levels several times a day, which often involves finger pricks and can be burdensome and painful.

In recent years, some noninvasive, wearable devices for measuring glucose have hit the market, but these devices are typically expensive and still depend on direct sampling and interaction with blood. However, a newly designed e-nose that can measure glucose levels based on a person’s breath could offer people with diabetes a different noninvasive and low-cost solution. The e-nose is described in a study published 7 June in IEEE Sensors Journal.

E-noses are devices that detect and analyze chemicals in the air in real time, determining the nature of the substance at hand. They are being designed for a wide range of tasks, including sniffing out good whiskey, monitoring crops, and detecting lung cancer.

Qiliang Li is a Professor in the Department of Electrical and Computer Engineering at George Mason University who’s been interested in developing similar technology for measuring glucose levels on a person’s breath. Although glucose isn’t exhaled in breath, the concentration of acetone and other ketones in the exhaled breath is associated with human metabolic conditions, including diabetes.

“To alleviate the pain and danger for the patients, we created an e-nose for noninvasive, painless, low-cost, and frequent diabetes testing,” says Li. “The e-nose is designed to identify the ‘smell’ of exhaled breath which contains certain level of acetone and other ketones. Therefore, the smell is an indicator of glucose level in the blood.”

The e-nose designed by Li’s team contains an array of 12 different chemical sensors and a microprocessor. When the e-nose sniffs the exhaled breath, the chemical sensors will send electrical response to the microprocessor, which processes the signals into digital information. “The e-nose will then analyze the digital information with our database and give a correct number of glucose levels,” explains Dr. Xiangdong Zhou, a professor at the Respiratory Department of Nanjing Medical University, in Nanjing, China, who was also involved in the study.

In their study, the researchers collected breath samples from 41 study participants with a range of glucose levels and used the data to train the e-nose with a range of machine-learning algorithms until they found a combination of models that could detect glucose levels on a person’s breath with 90.4 percent accuracy and an average error of 0.69 millimoles per liter (mmol/L) in blood glucose concentration.

Li notes that, although the system doesn’t directly measure glucose levels by blood, which is the current gold standard form of measurement, it offers several advantages. “The new e-nose enables noninvasive, painless, and low-cost measurement of glucose levels. It is designed for close monitoring of glucose levels for diabetes patients, especially for the patients with high blood sugar and Type 1 patients who need insulin medication frequently,” he says.

Next, Li says the team is interested in designing a new chip for the chemical sensor arrays to create a more precise e-nose. As well, he says, “We plan to recruit more patients with different body mass index (BMI), living styles, and diet for testing and build a comprehensive database of exhaled breath and glucose levels.”

The Conversation (3)
Roger Bohn21 Jul, 2022

So many research teams claim breakthroughs on non-blood glucose measurement. But they don't work out. Google, for example, claimed "smart contact lenses" in 2014. Measuring glucose some of the time is relatively easy. Measuring extremes, of people with unusual chemistry (due e.g. to illness), and rapidly is much harder. For a review of the topic see https://www.healthline.com/diabetesmine/non-invasive-diabetes-technology#what-skeptics-say .

FB TS15 Jul, 2022

I think there is a huge need for any health sensors which can be integrated into smartwatches! (For measuring blood pressure/sugar/alcohol/THC & for even detecting/measuring/timing pregnancies!)

Michael Wolfe22 Jul, 2022

Back in the '90s, the London Economist announced a new glucose sensor that did not require blood or strips. The patients placed their arm on the device and it detected their blood sugar. The 'inventor' was a great salesperson, and convinced the Economist that many of these would be purchased by the NHS since they saved the cost of strips, which are expensive, and patients were more willing to test their blood. Of course, it turned out to be a scam. The measurements were random, and had no correspondence with the actual blood sugar level.

It will be interesting to find out if this is another scam or a major advance in blood glucose mensuration.

Restoring Hearing With Beams of Light

Gene therapy and optoelectronics could radically upgrade hearing for millions of people

13 min read
A computer graphic shows a gray structure that’s curled like a snail’s shell. A big purple line runs through it. Many clusters of smaller red lines are scattered throughout the curled structure.

Human hearing depends on the cochlea, a snail-shaped structure in the inner ear. A new kind of cochlear implant for people with disabling hearing loss would use beams of light to stimulate the cochlear nerve.

Lakshay Khurana and Daniel Keppeler

There’s a popular misconception that cochlear implants restore natural hearing. In fact, these marvels of engineering give people a new kind of “electric hearing” that they must learn how to use.

Natural hearing results from vibrations hitting tiny structures called hair cells within the cochlea in the inner ear. A cochlear implant bypasses the damaged or dysfunctional parts of the ear and uses electrodes to directly stimulate the cochlear nerve, which sends signals to the brain. When my hearing-impaired patients have their cochlear implants turned on for the first time, they often report that voices sound flat and robotic and that background noises blur together and drown out voices. Although users can have many sessions with technicians to “tune” and adjust their implants’ settings to make sounds more pleasant and helpful, there’s a limit to what can be achieved with today’s technology.

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