A fluorescence turn-on probe for hydrogen sulfide and biothiols based on PET & TICT and its imaging in HeLa cells

In this paper, a photoinduced electron transfer (PET)& twisted intramolecular charge transfer (TICT)-based fluorescent probe (1) for detecting biothiols (GSH/Cys/Hcy) and hydrogen sulfide with fluorescence turn on was developed. The probe could recognize hydrogen sulfide over primary ions and selectively detect GSH/Cys/Hcy over other amino acids with fluorescence turn-on (an ESIPT process). H₂S can be distinguished from GSH/Cys/Hcy with wavelength shift by UV-Vis spectra. In addition, detection limits for H₂S/GSH/Cys/Hcy of probe 1 were 1.42 μM (0-100 μM), 0.13 μM (0-40 μM), 0.27 (0-30 μM), 0.22 μM (0-40 μM), respectively. The proposed thiolysis of the 2,4-dinitrochlorophenyl ether reaction in identification process was verified by the characteristic peak in ¹H NMR and HRMS spectra. Finally, the biological imaging experiments and low cytotoxicity investigations in HeLa cells demonstrated that probe 1 could provide a promising method for the determination of H₂S and biothiols in aqueous solution and living cells.