Artificial tongues have received increased attention due to their ability to detect the five basic tastes, but until now scientists have been unable to fully enable human tongue-like biomimicry for astringency in the lab. To mimic the mechanisms of human tongue-like perception of astringency, Jeonghee Yeom and a team of scientists in energy engineering and chemical engineering at the Ulsan National Institute of Science and Technology in the Republic of Korea, used a saliva-like, chemiresistive ionic hydrogel anchored to a flexible substrate to create a soft artificial tongue. They exposed the construct to astringent compounds and allowed hydrophobic aggregates to form in the microporous network, transforming it into a micro/nanoporous structure with improved ionic conductivity. Using the unique human tongue-like structure, they detected tannic acid (TA) across a wide spectrum (0.0005 to 1 weight percentage) with high sensitivity and a fast response time. As a proof-of-concept, the sensor detected the degree of astringency in beverages and fruits based on a simple wipe-and-detect method. The platform will have powerful future applications in humanoid robots and as taste monitoring devices, the research work is now published on Science Advances.
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Source: Phys.org