A dual-responsive fluorescent probe for detection of H2S and Cu2+ based on rhodamine-naphthalimide and cell imaging

A dual-site fluorescent probe based on naphthalimide and rhodamine was synthesized, which could rapidly and sensitively respond to H 2 S and Cu 2+ with different fluorescence signals. • The dual-responsive fluorescent probe ( DTR-1 ) for detection of H 2 S and Cu 2+ was developed. • DTR-1 could detect H 2 S and Cu 2+ within 1 min. • The LOD for H 2 S and Cu 2+ were calculated to be 0.035 μM and 0.16 μM, respectively. • DTR-1 was successfully applied to detect intracellular H 2 S and Cu 2+ . A highly selective and sensitive fluorescence probe ( DTR-1) for simultaneously detecting H 2 S and Cu 2+ with different fluorescence signals was synthesized. DTR-1 displayed remarkable fluorescence enhancement (560 nm, 34-fold) when H 2 S was added under excitation of 410 nm with the solution’s color change from dark to green. The limit of detection (LOD) for H 2 S was calculated to be 0.035 µM. By contrast, the addition of Cu 2+ enhanced obviously the emission intensity of DTR-1 with the maximal peak at 630 nm and color change from colorless to orange. LOD for Cu 2+ was determined to be 0.16 µM. The sensing mechanism for H 2 S and Cu 2+ in DMF/PBS (9/1, v/v, pH = 7.4) was studied by 1 H NMR and ESI-MS. Furthermore, the potential application of DTR-1 in biological systems had been demonstrated through imaging of living cells.