Oral-odor sensor diagnoses disease by detecting hydrogen sulfide in exhalation

  • November 16, 2021

The gas sensor platform is a technology that can monitor specific diseases in real-time by selectively sensing a tiny amount of biomarker gas related to various illnesses contained in people’s expiration, KIST said in a press release at the end of July 2021.  “Making diagnosis without blood collection or taking images, non-invasive respiratory monitoring is one of the key future technologies,” it said.  “The gas sensor platform selectively detects biomarker gas related to diseases from the breath, providing real-time monitoring of certain diseases.  By monitoring the changes in the concentration of certain gases in the breath, doctors can make the diagnosis of diseases.”

The non-invasive diagnosis is made through a series of processes, in which the breath collected in the Tedlar bag is injected into the thrum-sized sensor device, and rapid analysis of the gases is made in a few minutes.

In addition to water, acetone, toluene, ammonia, and hydrogen, the exhaled breath contains bad breath biomarkers — hydrogen sulfide, methyl mercaptan, and dimethyl sulfide.  Of these three biomarkers, it is important to detect hydrogen sulfide, found in bad breath patients selectively.  However, these biomarker gases are found only in very small amounts.  To selectively detect the targeted biomarker among the interrupting gases contained in the breath, further technological advancement is needed, it said.  The research team combined a small amount of sodium chloride (NaCl) or alkali metal salt with platinum (catalyst) nanoparticles to develop a sensor that selectively reacts to certain biomarker gas.  This combination of NaCl and platinum showed 10 to 200 times better performance in gas detection compared to sensors with the only platinum catalyst or with none of the catalyst.

The research team evaluated 80 cases of breath to find the gas sensor platform showing an accuracy of 86.3 percent in detecting bad breath.  A portable gas sensor that sniffs bad gas was commercialized with the combination of sensors for pressure, temperature, and humidity.  “By combining alkali metal-based catalyst with the widely used platinum catalyst, we could materialize highly sensitive and highly selective detector of biomarker gas,” Professor Kim Il-doo, who led the KAIST team, said.  “The development of the personal device that helps easy diagnosis of disease at home will reduce medical expenses and help people’s sustainable healthcare.”

The research results was published in the August 2021 issue of ACS Nano. It also was introduced in the ACS Weekly PressPac on 21 July 2021.  In addition, the developers have applied for the patent right for the device in various countries, including Korea, China, the U.S., and Europe, the KAIST said.

REFERENCE:  Korea Biomedical Review; 28 JUL 2021; Jung Jin-sol

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