A turn-on benzothiazole-based fluorescent probe for rapid cysteine detection in living cells

Abstract

Cysteine (Cys) is closely associated with many physiological and pathological processes in organisms and cells. The establishment of a molecular tool for the rapid and simple selective recognition of Cys would be of great benefit in the diagnosis and prevention of related diseases. In this paper, we developed a turn-on fluorescent probe BMBA, 3-(benzo[d]thiazol-2-yl)-4′-morpholino-[1,1′-biphenyl]-4-yl acrylate, designed with an acryloyl ester group to initiate the reaction and a benzothiazole moiety serving as the fluorescent component. Compared with other biological thiols, the probe BMBA possessed exceptional sensitivity and specificity for detecting Cys, boasting a low detection limit at 28.6 nM and a response duration of merely 5 min. The single-crystal data for the probe BMBA and compound 2 were successfully obtained and the recognition mechanism of Cys was investigated by FTIR spectroscopy and ¹H NMR. Most importantly, we effectively utilized BMBA for the detection of Cys in calf serum and living cells.