Organoselenium-based BOPHY as a sensor for detection of hypochlorous acid in mammalian cells

Highlights: • First organoselenium-based BOPHY probes were synthesized and confirmed with XRD. • The probes selectively and sensitively detect HOCl in water with "turn on" response. • Two phenylselenide quenched more fluorescence than one phenylselenide group on BOPHY. • The probe with one Se gave a faster response compared to the probe with two Se. • Utility of the probes for exogenous and endogenous HOCl was confirmed in MCF 7 cells. Phenylselenide substituted BOPHY probes (BOPHY-SePh and PhSe-BOPHY-SePh) were synthesized and characterized by NMR spectroscopy and single-crystal XRD. Both the probes selectively detect HOCl in water with high sensitivity over other reactive oxygen species. A fluorescence "turn-on" event was attained due to cease of the PET process through transformation of selenide to selenoxide. Both the probes react with HOCl in less than 1 s. PhSe-BOPHY-SePh probe depicted low background fluorescence due to presence of two phenylselenide groups at BOPHY. PhSe-BOPHY-SePh probe has a low detection limit (0.63 μM) than BOPHY-SePh probe (1.08 μM). The bioimaging studies of both the probes were carried out in MCF 7 cells. Both the probes exhibited a good fluorescence response for HOCl in vitro and in mammalian cells. In addition, the probes showed reversibility with all bio-thiols, which was validated in MCF 7 cells using GSH.