gas sensor for monitoring lipolysis
Scientists at ETH Zurich developed a highly accurate gas sensor for monitoring lipolysis by testing a person’s exhalations during exercise.
“When burning fat, the body produces bi-products that find their way into the blood,” explains, Andreas Güntner, a postdoc in the ETH. In the pulmonary alveoli, these molecules enter the air exhaled by the person.
The unexpected change of these lipid metabolites is acetone. Güntner and his colleagues have developed a small gas sensor that measures the presence of this substance. The sensor can detect a single acetone molecule in hundred million molecules.
The researchers tested the functioning of the sensor in volunteers while they exercised. Researchers asked the test subjects to blow into a tube that connected to the acetone sensor at regular intervals.
Researchers said, the measurements showed that lipolysis in some test subjects did only start towards the end of the training session. In the other volunteers, the measurements showed that their bodies began burning fat much sooner.
Control measurements showed that the new measurement method agreed well with the concentration of the bio-marker beta-hydroxybutyrate in the blood of the test subjects. This blood analysis monitors lipolysis.
special semiconducting nanoparticles
While designing the sensor, the scientists use a chip coated with a porous film of special semiconducting nanoparticles. The particles are tungsten trioxide with single atoms of silicon.
Tungsten trioxide nanoparticles interact with acetone if the atoms of the nanoparticles arranged in a certain crystalline structure. The interaction reduces the electrical resistance of the chip coated with the nanoparticles, and this phenomenon can measure.
The idea of the chip is to diagnose diabetes, because the exhaled breath of patients with untreated type-1 diabetes contains high concentrations of acetone. However, the scientists shown that the sensor detect the very low acetone concentrations in a person’s exhalations during exercise.
The chip used in this study is the size of a 1-cent euro coin, but the researchers working to refine the measurement technology. So that, it will be possible with smaller chips. The goal is to offer the chip in a manageable sized device. This would allow athletes and people who want to lose weight to check for themselves when their bodies begin to burn fat so that they can optimize their training regimen.
Highly sensitive acetone measurements already possible with other instruments. For instance, mass spectrometers, which are large laboratory devices that cost several hundred thousand Swiss francs. The researchers using these instruments in the current study to verify their measurements. Portable acetone breath tests also already exist, but they can only be used once and take several minutes before they show the results.
More information: [Analytical Chemistry]