E-Tongues/Noses Based on Conducting Polymers and Composite Materials: Expanding the Possibilities in Complex Analytical Sensing

Abstract

Conducting polymers (CPs) are extensively studied due to their high versatility and electrical properties, as well as their high environmental stability. Based on the above, their applications as electronic devices are promoted and constitute an interesting matter of research. This review summarizes their application in common electronic devices and their implementation in electronic tongues and noses systems (E-tongues and E-noses, respectively). The monitoring of diverse factors with these devices by multivariate calibration methods for different applications is also included. Lastly, a critical discussion about the enclosed analytical potential of several conducting polymer-based devices in electronic systems reported in literature will be offered.

Self-Healing E-tongue

“…As a proof of concept, the electrical differences of these composites were exploited to combine unspecific, overlapping signals from raw data to form a fingerprint of the analyzed samples. , We first tested the device with basic tastes (sweetness, saltiness, sourness, bitterness, and umami), in triplicate and with independent measurements, using statistical analysis of each sensing unit from raw impedance data in the whole frequency range, illustrated in Figure as a score plot in principal component analysis. Briefly, PCA is an unsupervised machine learning method that reduces the system dimensionality by making a more representative choice from linear combinations of the original data.…”

“…Briefly, it deeply influenced multisensory analytical devices usually coined as e-noses and e-tongues, comprising nonspecific sensing units for the physical or chemical transduction of unspecific overlapping signals to form a fingerprint of measured samples. 34,35 After an extensive search to manufacture self-healing conductors by design, balancing the healing and electrical capabilities, four different self-healing composites are used here as sensing units in the first designed self-healing e-tongue. As a proof-of-concept, the device easily distinguishes basic tastes (sweet, bitter, sour, salt, and umami) below the human threshold and detects trace levels of glucose in artificial sweat.…”

“…Although the gustative neuronal system is well-known, indicating specific brain areas responding to tastes, the internal pathways in the brain for taste recognition is poorly understood and still broadly studied. − Despite the complexity involved, progress in comprehending the biological system deeply impacted the concepts involved in sensors mimicking the human gustatory system. Briefly, it deeply influenced multisensory analytical devices usually coined as e-noses and e-tongues, comprising nonspecific sensing units for the physical or chemical transduction of unspecific overlapping signals to form a fingerprint of measured samples. , After an extensive search to manufacture self-healing conductors by design, balancing the healing and electrical capabilities, four different self-healing composites are used here as sensing units in the first designed self-healing e-tongue. As a proof-of-concept, the device easily distinguishes basic tastes (sweet, bitter, sour, salt, and umami) below the human threshold and detects trace levels of glucose in artificial sweat.…”

Coatings Comprised of Graphene Oxide Decorated with Helical Polypyrrole Nanofibers for Microwave Absorption and Corrosion Protection

“…It is worth noting that conductive polymers (CPs), such as polypyrrole (PPy) and polyaniline, have the characteristics of adjustable conductivity, − low density, passivation effect, − and stable physical and chemical properties. − The above characteristics make them possess great application potential in the field of microwave absorption and anticorrosion. , However, conductive polymers (CPs), used as MA materials, have limited MA strength and relatively narrow effective bandwidth. Furthermore, they face difficulty in dispersing uniformly in solvents due to poor solubility, which greatly limits their practical applications …”

Quick classification of strong-aroma types of base Baijiu using potentiometric and voltammetric electronic tongue combined with chemometric techniques

“…The electronic tongue (E-tongue) is a kind of human sensory simulating system, which consists of a number of low-selective sensors and uses advanced mathematical procedures for signal processing based on pattern recognition and multivariate data analysis ( 12 ). In recent years, E-tongue has been widely used for the analysis of wines, fruit juices, coffee, milk, and beverages, in addition to the detection of trace amounts of impurities or pollutants in waters ( 13 , 14 ).…”