Fig. 5.

The spectrofluorometric characteristics of the (a–c) PAVSD800-2 and (d) the di-SC2(5). (a) The emission spectrum of the dye PAVSD800-2 at $6\mu \mathrm{M}$ concentration, where vesicles prepared in ${\mathrm{K}}^{+}$ buffer are diluted into isotonic ${\mathrm{Na}}^{+}$ buffer to generate a membrane potential upon addition of valinomycin. (b) Negative control, where ${\mathrm{K}}^{+}$ buffer is used for both the inside and outside. (c) The fluorescence emission at 820 nm for different concentrations. (d) Fluorescence emission spectrum of the dye, di-SC2(5) at $6\mu \mathrm{M}$ concentration.