A ratiometric fluorescent probe based on a novel fluorophore with high selectivity for imaging cysteine in living cells

As a biothiol, cysteine (Cys) is essential to both physiological and pathological processes and has been associated with many diseases, including neurological disorders, rheumatoid arthritis, and renal dysfunction. Therefore, the development of a high‐performance probe for detecting Cys levels can help prevent and diagnose disease. In this study, a ratiometric fluorescent probe based on a novel fluorophore was developed for detecting Cys, and it showed high specificity and a rapid response time toward Cys. This probe demonstrates excellent biocompatibility and has been utilized effectively for the imaging of Cys in living cells.