Highly Stable Potentiometric Umami Taste Sensor Using PEDOT:SDS-Based All-Solid-State Electrode Modified With Lipid/Polymeric Membrane

Taste has become one of the most decisive factors for consumers to choose and purchase food products. This has triggered the food research communities to further develop high-performance artificial taste sensors that are able to detect five basic taste qualities including umami. Despite their high selectivity and low limit of detection (LoD), the currently available umami sensors employing taste receptor type 1 member 1 (T1R1) still suffer from high fabrication cost and low stability, limiting their use in ubiquitous and continuous food quality monitoring. Here, we developed a highly stable potentiometric umami taste sensor designed in all-solid-state electrode (ASSE). Intermediate layer based on poly(3,4-ethylenedioxythiophene) doped with sodium dodecyl sulfate (PEDOT:SDS) is used to stabilize the sensor response. A lipid/polymeric membrane (LPM) comprising bis(2-ethylhexyl) phosphate (BEHP) and methyltrioctylammonium chloride (TOMACl) serves as the umami sensing element. A low-frequency areal capacitance of 6.42 mF/cm2 is revealed. While BEHP is responsible for the umami sensing, adding TOMACl to the membrane enhances membrane conductivity and sensing linearity. Besides being able to quantify taste and aftertaste (richness) of various umami substances ranging from 0.1 to 300 mM, the fabricated sensors demonstrate fast response, high reusability, and long-term stability. These high-performance characteristics pave the way for them to potentially replace conventional sensory evaluation in future.