Dioxins and Dioxin-Like Compounds: Current Challenges in Sensing and Future Perspectives

Polychlorinated dibenzo-<i>p</i>-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are highly toxic, persistent organic pollutants that pose severe environmental and public health risks due to their widespread distribution in air, water, and soil. Although global emissions have decreased from 287 kg I-TEQ to 97 kg I-TEQ by 2025, concerning concentrations persist in environmental matrices, with soil contamination ranging from 0.017 ppt in China to 540,000 ppt in Japanese paddy fields. These observations highlight the urgent need for sensitive, selective, and rapid detection strategies capable of addressing trace-level dioxin contamination. Conventional analytical approaches, including gas chromatography mass spectrometry (GC-MS), high-resolution mass spectrometry (HRMS), biosensors, and optical detection techniques, have facilitated monitoring efforts but remain limited by high cost, operational complexity, restricted stability, and suboptimal selectivity. Cyclodextrin (CD)-based sensing platforms have demonstrated significant success in detecting a wide range of environmental pollutants owing to their well-defined hydrophobic cavities and lipophilic interiors, which enable the formation of stable inclusion complexes in aqueous environments. Given the strongly lipophilic nature of dioxins, CDs are conceptually well-suited as recognition scaffolds for selective molecular binding. However, to date, no experimental CD-based fluorescent or colorimetric systems have been reported for dioxin detection, and investigations have been limited to computational simulations predicting binding affinity and selectivity. These insights underscore a critical gap in sensor development and highlight the potential of CD-derived optical sensors as a next-generation platform for highly selective, sensitive, and rapid dioxin monitoring.