Synthesis of selenium-based BOPHY sensor for imaging of Cu(II) in living HeLa cells

•Organoselenium-based BOPHY probe for the selective and sensitive detection of Cu(II).•Probe showed fluorescence turn-on response in less than 1 s upon reaction with Cu(II).•The probe detected Cu(II) in nanomolar range (10.8 nM).•Utility of the probe for detection of Cu(II) was confirmed in HeLa cells. NSe2 chelating moiety embedded BOPHY probe was synthesized and characterized. The probe displayed high selectivity and sensitivity for the detection of Cu(II). The probe reacted with Cu(II) in less than 1 s and showed a 6 fold increment in fluorescence intensity. Detection limit of the probe was found to be 10.8 nM and the binding ratio of the complex (Probe:Cu(II)) was determined to be 1:1 from the Job's plot. In addition, the probe exhibited reversibility with S2− ions. The probe possessed cell-membrane permeability and sensitive detection of Cu(II) in live HeLa cells with strong green fluorescence. [Display omitted]