Cutting-edge advances in colorimetric and fluorescent chemosensors for detecting lethal cyanide ion: A comprehensive review

Abstract

Anions, specifically cyanide, occupy crucial roles in various biological, physiological, and industrial contexts. While cyanide is indispensable as a raw material in the synthesis of herbicides, resins, synthetic fibers, and the gold-extraction process, its widespread presence causes a significant threat to both environmental and social systems. Cyanide abundance in the environment arises not just from industrial effluents but also from the natural biological processes of fungi and algae. The dual nature of cyanide, serving both as a useful industrial component and a potential environmental hazard, highlights the importance of responsible management and regulation in its production and application. The detection of cyanide has become a matter of paramount importance due to its extreme toxicity and potential environmental contamination, where even micromolar levels can prove fatal to humans. In addressing this critical concern, researchers have focused on developing simple, inexpensive, and rapid detection methods, with chemosensors emerging as among the most promising solutions. These chemosensors rely on colorimetric and fluorometric responses, offering a synergistic combination that enhances the versatility of cyanide detection methodologies. Through novel design and synthesis, researchers have constructed a diverse range of chemosensors with tailored properties, such as high selectivity, low detection limits, and rapid response times. Especially, efforts have been directed towards making these detection systems portable and user-friendly, facilitating their practical implementation in real-world scenarios. This comprehensive review provides a focused examination of colorimetric and fluorescent probes designed for the specific and sensitive recognition of cyanide anions. Emphasizing their applicability in on-site portable strips and cellular imaging, the review aims to enhance readers' understanding of the critical need for monitoring cyanide ions in the context of human health and disease. The discussed probes are categorized into various classes, including small molecules, metal complexes, metal–organic frameworks (MOFs), macrocyclic compounds, nanomaterials, and polymer-based probes, each classified based on their structural properties and functional groups. Encompassing advancements made in the field from 2021 to 2023, the review underscores the progress achieved in developing these probes. Finally, the review addresses the potential future applications of colorimetric and fluorescent probes in detecting cyanide ions, pointing towards the evolving landscape of analytical techniques and their significance in advancing our ability to monitor cyanide levels effectively.