Electronic tongue: active channels, molecular sieves, receptors and arrays

Abstract

Electronic tongues (E-tongues) have emerged as innovative sensing platforms that mimic the human gustatory system, enabling the precise analysis of complex chemical mixtures. Recent advances in E-tongue technologies have been driven by developments in four fundamental components: active channels, molecular sieves, receptors and arrays. These advancements contribute to enhanced sensitivity, selectivity and functionality in taste sensing systems. The atomic-scale thickness and high surface-area-to-volume ratios of two-dimensional (2D) materials, including graphene, MXenes and transition metal dichalcogenides, make them effective active channels that significantly improve sensitivity and selectivity. Analytes can be precisely separated and filtered from complex solutions using molecular sieves such as metal–organic frameworks, covalent organic frameworks and polymer membranes. Engineered receptors, which can be synthetic macrocyclic compounds or biological types such as enzymes and aptamers, enable targeted interactions with specific taste molecules. For real-time monitoring, sophisticated sensor arrays, including ion-sensitive field-effect transistors and triboelectric sensor arrays, convert chemical interactions into measurable electrical signals. By combining these advanced components, E-tongue systems can achieve unprecedented accuracy and reliability in a variety of applications, from environmental monitoring to biomedical diagnostics and food quality evaluation.