Eco-Friendly Tongue Depressor Evaluates a Range of Health Conditions

An eco-friendly disposable sensor that can check levels of glucose and other biomarkers in saliva has been incorporated into wooden tongue depressors. This easy-to-produce device could someday help doctors assess a range of conditions. Doctors usually use tongue depressors while examining the patient’s mouth and throat but now the same flat wooden spatula can actively evaluate the patient’s health. The elaboration of this discovery is reported in ACS’ Analytical Chemistry.

Wood is a renewable, biodegradable, natural material that is widely available at low cost, which makes it attractive for researchers who design electronics and sensors. However, this is challenging because the material is not good at conducting electricity.

Wooden Tongue Depressor Multiplex Saliva Biosensor Fabricated via Diode Laser Engraving

One solution is to use wood as a passive substrate and then coat it with metals and carbon-based inks. Alternatively, high-power lasers can char specific regions on the wood, turning those spots into conductive graphite. But this complicated technique requires sophisticated and expensive instrumentation, an oxygen-free atmosphere, and fire retardants.

To develop a cheaper and easier process, researchers turned to low-power diode lasers. They have already been successfully used to make polyimide-based sensors but haven’t previously been applied to wooden electronics and electrochemical sensors.

Therefore, 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 measure concentrations of nitrite and glucose rapidly and simultaneously in artificial saliva. Nitrite can reveal oral diseases, such as periodontitis, while glucose can serve as a diagnostic for diabetes. These low-cost devices could be adapted to detect other saliva biomarkers and would be quick and easy to produce on-site at medical facilities.

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Source-Eurekalert