Electrochemical cells etched by a laser on a wooden tongue depressor can measure glucose and nitrite levels in saliva. (WE = working electrode, CE = common counter electrode, RE = common reference electrode). Credit: Adapted from Analytical Chemistry, 2023, DOI: 10.1021/acs.analchem.3c01211
Key points:
- A new tongue depressor with a disposable sensor can check levels of glucose and other biomarkers in saliva.
- The researchers used low-power diode lasers to “engrave” the wood, making the device both low-cost and easy to produce.
- Beyond nitrite and glucose, the system can be adapted to detect other disease biomarkers
One of the worst parts about having strep or a similar illness is the gold standard assessment: a dry, wooden tongue depressor that feels like you're eating sandpaper. Perhaps it wouldn’t be so bad if the tongue depressor was actively evaluating your health?
That’s the goal of a research team in Greece who has designed an ecofriendly disposable wooden spatula that can check levels of glucose and other biomarkers in saliva.
To do so, Christos Kokkinos and colleagues at the National and Kapodistrian University of Athens turned to low-power diode lasers, which have already been successfully used to make polyimide-based sensors but haven’t previously been applied to wooden electronics and electrochemical sensors.
According to the study, published in ACS’ Analytical Chemistry, the researchers used a portable, low-cost laser engraver to create a pattern of conductive graphite electrodes on a wooden tongue depressor, without the need for special conditions. Those electrodes formed two electrochemical cells separated by lines drawn with a water-repellent permanent marker.
The biosensor was then used to rapidly and simultaneously measure concentrations of nitrite and glucose in artificial saliva—nitrite can reveal oral diseases such as periodontitis, while glucose can serve as a diagnostic for diabetes.
Given the success of the device, the team says it can be adapted to detect other saliva biomarkers. Additionally, the low-cost devices would be quick and easy to produce on-site at medical facilities to help doctors assess a range of conditions.