A new fluorescent ‘turn on’ probe for rapid detection of biothiols

We designed and synthesised a novel molecular probe exhibiting high selectivity and sensitivity towards reactive sulphur species (RSS) over other amino acids and biologically relevant species, as well as scrutinised its spectroscopic behaviours under physiological conditions and in living milieu. We used an electrophilic cyanate group as a masking agent to block the excited state intramolecular proton transfer process of 2-(2-cyanato-3-methoxyphenyl)benzo[d]thiazole (HMBT-OCN), which readily hydrolyses to the highly fluorescent structure, 2-(2ʹ-Hydroxy-3ʹ-methoxyphenyl)benzothiazole (HMBT-OH), in the presence of reactive sulphur species.