Fig. 4.

a Schematic diagram of the in vivo working mechanism of DSF@Cu-HMSNs enhanced chemotherapy. b TEM image and SAED pattern of PEG-Cu-HMSNs. c Accumulated release of copper ions from PEG-Cu-HMSNs at varied pHs. d The electron spin resonance (ESR) spectroscopy under different conditions (only H₂O₂; DSF@PEG/Cu-HMSNs + H₂O₂, pH = 7.4; DSF@PEG/Cu-HMSNs + H₂O₂, pH = 6.5). e Chemical mechanism of Cu-mediated reactions. f Cell viabilities of 4T1 cells after different treatments. g Schematic illustration of the synthesis of DSF/DOX@ZIF-8@Cu-TA. h TEM images of different nanoparticles. i Schematic diagram of the in vivo DSF/DOX@ZIF-8@Cu-TA triggered synergistic chemotherapy and CDT