Fig. 1. (A and B) Absorption spectra of SiR (2 μM) treated with Cys (20 μM) or pretreated with GSH (1 mM) for 5 min and then treated with Cys (20 μM) for 10 min. (C and D) Time-dependent fluorescence spectra of SiR (2 μM) treated with Cys (20 μM) for 30 min or pretreated with GSH (1 mM) for 5 min and then treated with Cys (20 μM) for 30 min. The spectrum was recorded every minute. Conditions: PBS (10 mM, pH 7.4); λex = 488 nm and λem = 620 nm.
