Recent Advances in Colorimetric and Fluorescent Chemosensors for Cu⁺ Ions: Trends, Challenges, and Future Directions.

The detection of copper ions (Cu⁺) through colorimetric and fluorometric methods has garnered significant attention due to the biological, environmental, and medical importance of Cu⁺. These detection techniques have proven to be highly effective due to their simplicity, cost-efficiency, high sensitivity, and suitability for bioimaging applications. This critical review begins by briefly addressing the sources, applications, and toxicity of copper ion sensors. It then provides an in-depth classification of fluorescent and colorimetric Cu⁺ sensors based on their receptors, organizing them into various categories such as anthracene, pyridine, pyrazole, pyrrole, naphthalene, imidazole, and quinoline functionalized sensing systems, with a focus on developments since 2016.