Figure 4.

(a) Chemical structures of the saccharides examined in this study (from mono- to hexa-saccharides). (b) Fluorescence spectra (λ_ex 485 nm) of Rhod-Cur (80 μM in monomer unit) in the absence (black) and presence of acarbose (25, 50, 75, 100, 125, 150, 175, and 200 μM, colored lines) in 1:9 (v/v) DMSO-H₂O at room temperature; the fluorescence intensities were corrected by the absorbances at the excitation wavelength. (c) ΔInt. (λ_obs 573 nm) data obtained from (b) were plotted as a function of the acarbose concentration; ΔInt. represents the delta fluorescence intensity; ΔInt. = 7.38 [acarbose (μM)]. (d) ΔInt. (λ_obs = 575 nm) of Rhod-Cur (80 μM in the monomer unit) induced upon complexation of the tested saccharides (100 μM). (e) ΔInt. data obtained from (d) plotted as a function of saccharide length. (f) Schematic illustration of the fluorescence “turn-on” change based on the globular expansion.