An ESIPT-based ratiometric fluorescent probe for cysteine and its application in complex matrices: milk and fetal bovine serum.
Cysteine (Cys) was an essential biothiol whose dysregulation is linked to neurotoxicity, liver injury, childhood growth retardation, and cardiovascular diseases, making its accurate detection critical for clinical diagnosis and biochemical research. Although excited-state intramolecular proton transfer (ESIPT)-based fl...