2023-08-29 11:15:20
A prototype sensor that measures the level of glucose in saliva could in the not too distant future offer a simple, fast and painless way for people with diabetes to monitor said level.
Diabetes is a disease that occurs when the body cannot regulate its blood glucose levels. Elevated glucose levels can lead to cardiovascular disease and other conditions, so it is vital that people with diabetes keep their blood glucose levels at moderate levels.
People with diabetes have traditionally monitored their blood glucose using devices that test a drop of blood and require pricking a finger several times a day. A further development is that of implanted sensors, which can provide constant glucose monitoring without unpleasant pinpricks, but these devices may be less accurate at measuring low glucose levels and are not suitable for everyone with diabetes.
A more convenient way to monitor glucose might be through saliva testing, since glucose levels in saliva correlate with glucose levels in the blood. However, glucose concentrations are much lower in saliva than in blood, which has made it difficult to accurately measure without sophisticated laboratory equipment.
Abhinav Sharma’s team, from the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, have created a highly sensitive glucose detector based on a thin-film transistor.
These small, lightweight, and low-power devices could be well-suited for the mass production of cheap, throwaway sensors. An easy-to-use, non-invasive glucose measurement device that uses saliva as a test sample could change the lives of millions of patients around the world, says Sharma.
KAUST researchers have developed a sensor that can measure glucose levels in saliva, offering people with diabetes an alternative means of monitoring blood glucose levels. (Image: © 2023 KAUST; Anastasia Serin)
The transistor contains thin layers of the semiconductors indium oxide and zinc oxide, capped with the enzyme glucose oxidase. When a saliva sample is placed on the sensor, the specific enzyme oxidizes the glucose present to produce D-gluconolactone and hydrogen peroxide. The electrical oxidation of hydrogen peroxide produces electrons that enter the semiconductor layers. That changes the current that flows through the semiconductors, and the magnitude of this effect indicates the concentration of glucose within the sample.
The researchers tested their device using human saliva samples spiked with different amounts of glucose, and they also tested saliva from volunteers.
They found that the device correctly measures a wide range of glucose concentrations in less than a minute. Most importantly, the sensor did not mistake other substances in saliva for glucose.
Although the sensitivity of the device decreased over time, it still performed well after being stored for two weeks at room temperature.
The team is now developing a series of transistor sensors that could simultaneously detect multiple metabolites in saliva. The development of wearable sensor arrays that can be integrated with a smartphone is a possible future direction for research.
Sharma and his colleagues discuss the technical details of the new sensor in the academic journal Biosensors and Bioelectronics, under the title “Non-invasive, ultrasensitive detection of glucose in saliva using metal oxide transistors.” (Source: NCYT from Amazings)
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