Development of a cobalt (II) and 1,10-phenanthroline carboxaldehyde-based fluorescent probe for the detection of cysteine

Effective cysteine (Cys) detection is extremely important for early disease monitoring and diagnosis. In this study, a fluorescent probe (PHO) comprising 1,10-phenanthroline carboxaldehyde as the ligand and cobalt as the central ion was synthesized to detect Cys. The synthesized PHO exhibited enhanced fluorescence at 603 nm in the presence of Cys in HEPES buffer. Furthermore, the probe detected Cys concentrations as low as 0.6 μmol/L, demonstrating high sensitivity. Additionally, a strong linear relationship was established between the Cys concentration and normalized intensity of fluorescence. Importantly, the high selectivity was retained even in the presence of other interfering compounds. Consequently, this method can serve as a novel approach for detecting Cys in physiological systems.