Fig. 2.

GSH depletion, O₂ production and ROS generation assay. a) UV–vis absorption spectra of DTNB treated with GSH alone, GSH + CMS and GSH + H₂O₂, respectively. Inset: the digital photograph of the corresponding solution. b) The corresponding absorbance at 412 nm vs time for two different treatments (GSH and GSH + CMS). c) Dissolved O₂ concentration vs time in solutions with H₂O₂, CMS and CMS + H₂O₂, respectively. d) Dissolved O₂ concentration vs time in solution with CMS + H₂O₂ at varied H₂O₂ concentrations. e) UV–vis absorption spectra of MB in NaHCO₃ buffer under different treatments (Blank, H₂O₂, CMS and CMS + H₂O₂). Inset: the digital photograph of the corresponding solution. f) The corresponding absorbance at 664 nm vs time for different treatments (Blank, H₂O₂, CMS and CMS + H₂O₂). g) ESR spectra of H₂O₂ and CMS + H₂O₂ using DMPO as the ·OH trapping agent. h) Schematic diagram of GSH depletion and catalytic H₂O₂ decomposition feature of CMS with multi-valent Mn.