Fig. 5

Cu-engineered HMPB for PTT enhanced intratumoral chelating for tumor-specific synergistic therapy based on the nontoxicity-to-toxicity transition of DSF. a Schematic diagram of the fabrication of DSF@PVP/Cu-HMPB and b the in vivo PVP/Cu-HMPB triggered PTT enhanced chemotherapy. c TEM images and corresponding elemental mapping of DSF@PVP/Cu-HMPB. Scale bars 50 nm. d Temperature change curves of PVP/Cu-HMPB under light irradiation and subsequently after turning off the light source. e Absorbance of DSF@PVP/Cu-HMPB solution in the range of 200–600 nm at different time intervals. f Cell viabilities of 4T1 cells after being treated by different conditions for 24 h. g Weight of tumors in different groups of BALB/c nude mice at the end of treatment. h The blood-circulation lifetime of PVP/Cu-HMPB. i Biodistribution of PVP/Cu-HMPB-derived Cu²⁺ at different time durations after injecting PVP/Cu-HMPB. j Bioluminescence images of mice's main organs. k, l Body weight of mice in different groups