Fig. 1. GSH-activatable response of prodrug Cy-S-CPT (5 μM) with the titration of GSH (0, 1, 5, 10, 15, 25, 35, 50, 75, 100, 150 and 250 μM) and incubation for 15 min in a mixture solution of DMSO/PBS (40/60, pH = 7.4, 10 mM) at 37 °C: spectral change in absorption (A) and emission ((B), λex = 530 nm; (C), λex = 750 nm), and time dependence of fluorescence intensity (D) at 650 nm in the presence of GSH (250 μM) upon excitation at 530 nm.
