Fig. 1.
a Absorbance spectra of TA1 (10 μM) in the absence of Na2S3 (black line), upon addition of Na2S3 (red line) (100 μM, 10 mM PBS buffer, 0.2% DMSO, 100 μM CTAB). b Time-dependent fluorescence spectral changes of TA1 (10 μM) λex = 512 nm, λem = 542 nm, upon addition of Na2S3 (100 μM, 10 mM PBS buffer, 0.2% DMSO, 100 μM CTAB). c Fluorescence intensity changes of TA1 (10 μM) in the absence of Na2S3 (blue sphere), upon addition of Na2S3 (red sphere). d Fluorescence responses of TA1 (10 μM) toward addition of a range of concentrations of Na2S3 (0 to 10 μM). e Linear relationship between the fluorescence intensity and Na2S3 concentrations. Data were acquired in 10 mM PBS buffer (0.2% DMSO, 100 μM CTAB) after incubation with Na2S3 for 2 min at 37 °C. λex = 512 nm, λem = 542 nm. f Two-photon absorption (TPA) cross-sections spectra of TA1 (10 μM) upon addition of Na2S3 (100 μM, 10 mM PBS buffer, 0.5% DMSO, 100 μM CTAB). g Fluorescence responses of TA1 (10 μM) to biologically relevant species. Each bar represents fluorescence increases of TA1 at 542 nm to 100 μM Na2S3 or other species. 1) 1 mM GSH; 2) 500 μM Cys; 3) 500 μM Hcy; 4) 100 μM Alanine; 5) 100 μM Serine; 6) 100 μM Arginine; 7) 100 μM Isoleucine; 8) 100 μM Lysine; 9) 100 μM Ascorbic acid; 10) 100 μM Na2S2O3; 11) 100 μM NaHSO3; 12) 100 μM Na2S; 13) 100 μM Na2S + 50 μM ClO–; 14) 100 μM Na2S3. The data were acquired in 10 mM PBS buffer (0.2% DMSO, 100 μM CTAB) after incubation for 30 min. λex = 512 nm. (Color figure online)