Hydrogel-based Bioelectronic Tongue for the Evaluation of Umami Taste in Fermented Fish

Abstract

Bioelectronic tongues based on umami taste receptorshave recentlybeen reported for versatile applications such as food analyses. However,their practical applications are still limited, partly due to theirlimited stability and non-specific responses in real sample environments.Herein, we have developed a hydrogel-based bioelectronic tongue forthe sensitive assessment of umami intensity in fish extract samples.In this study, the T1R1 venus flytrap of an umami taste receptor wasimmobilized on the gold floating electrodes of a carbon nanotube-basedfield-effect transistor. A polyacrylamide conducting hydrogel filmwas further hybridized on the sensor surface via physical adsorption,which could provide a good physiological environment to maintain theactivity of receptors due to its excellent hydrophilicity and biocompatibility.The bioelectronic tongue with a receptor-embedded hydrogel structureshowed a sensitive detection of umami substances down to 1 fM, andit also had a wide detection range of 10(-15)-10(-2) M for monosodium glutamate and disodium inosinate,which covers the human taste threshold. More importantly, the proposedsensor could significantly reduce the non-specific binding of non-targetmolecules to a carbon nanotube channel as well as exhibit long-termstability, enabling sensitive detection of umami substances even infish extract samples. Our hydrogel-based bioelectronic tongue providesa promising platform for future applications such as the flavor evaluationof foods and beverages.