Fig. 6. (A) pH-dependent phosphorescent images of 2-labeled A549 cells. The cells were incubated with 2 (10 μM, λex = 405 nm, λem = 580 ± 30 nm) for 12 h, and then treated with nigericin solutions (20 μM) at pH 5.0, 6.5 and 7.4 for 10 min. (B) Comparison of the intracellular phosphorescence intensity of 2 in the presence of nigericin at different pH values. Data are expressed as the mean ± SD (standard deviations). Number of cells: 10.
