FRET-based dual channel fluorescent probe for detecting endogenous/exogenous H₂O₂/H₂S formation through multicolor...

We have developed a FRET-based fluorescent probe (PHS1) as a combination of two different fluorophores (coumarin and naphthalimide); which can detect both exogenous and endogenous H₂S and H₂O₂ in live cells through multicolor images. The precise overlap between UV-absorption of naphthalimide and the emission band of coumarin in probe PHS1 allows the acquisition of the self-calibrated information of dual analytes through FRET-based imaging. The UV-Vis absorption (λ_abs 390 nm) and fluorescence emission (λ_em 460 nm) of probe PHS1 in the presence of H₂O₂ are increased ∽35- fold and ∽15-fold respectively. It also allows the estimation of the levels of H₂S through enhancement of emission intensity at 550 nm. The probe PHS1 exhibits high stability against various analytes, including various pH (4-9.5). The cell viability assay data indicate that the probe is not harmful to the cancer cells. The nontoxic nature of the probe PHS1 encourages application for cancer cell labeling. The probe PHS1 can detect the level of endogenous H₂O₂, H₂S, and H₂O₂/H₂S in cancer cells through blue, green and FRET-based green channel imaging. PHS1 is a unique probe, has potential application for diagnosing cancer by providing information on the level of dual analytes (H₂S, H₂O₂) in cancer cells.