Photophysical Properties of Fluorescent Probe Thioflavin T in Crowded Milieu

Figure 3

ThT fluorescence lifetime in aqueous solution, in aqueous-glycerol solutions, and in aqueous solutions in the presence of crowding agents. The excitation laser impulse profiles (black curves), experimental fluorescence decay curves (light blue circles), best-fit for a three-exponential decay models (blue curves), and the deviation between the experimental and calculated decay curves (grey circles) for ThT in aqueous solutions in the presence of PEG-400 and glycerol 46% are shown on (a) and (b), respectively. For comparison on (a) and (b) experimental fluorescence decay curves (light green circles) and best-fit calculated fluorescence decay curve (green curves) for ThT in aqueous solution are also represented. is the number of registered impulses in the time interval normalized to unity in the maximum. The dependence of ThT fluorescence lifetime on the concentration of PEG-400 and glycerol is shown on (c) and (d), respectively. The results presented on (a), (b), and (c) were obtained with the use of spectrometer FOG100; the data presented on (d) for low concentrations of glycerol were obtained with the use of spectrometer FOG100 (red circles) and for high concentrations of glycerol were obtained with the use of spectrometer FluoTime 300 (blue circles).

(a)

(b)

(c)

(d)