TME-targeting nano-theranostic agent for NIR fluorescence diagnosis and O2-economized PDT-based multimodal synergistic therapy

The accurate diagnosis and effective therapy of malignant tumors is still a challenge owing to its poor prognosis, recurrence, and drug resistance. In this study, a tumor microenvironment responsive and high O2-economic effect nano-theranostic agent GOx@NPs was constructed through the self-assembly of GOx and CDDO-Fe, which was synthesized by coupling natural chemotherapeutic drug CDDO-Me blocked by ferrocene (Fc) with near-infrared (NIR) fluorescence probe hemicyanine (I-CyOH) via redox-responsive linker dimercaptoisopropionyl, and then introducing tamoxifen (estrogen receptor target fragment) to hemicyanine to enhance the active tar-geting ability. The NIR fluorescence probe I-CyOH not only achieved an accurate diagnosis, but also possessed photodynamic therapy (PDT) effect. The active targeting fragment tamoxifen enhanced the accumulation of pathological site and alleviated the hypoxia microenvironment through the inhibition of mitochondrial respi-ratory to reinforce the PDT efficiency of I-CyOH. Moreover, the combination of Fc and GOx could achieve starvation therapy and enhance chemodynamic therapy (CDT). In vitro and vivo experiments exhibited that the effective dual sensitive synergistic therapy possessed significant therapy efficiency and lower side effects. This study provides a valuable strategy for constructing dual sensitization and high economic of intelligent nano-theranostic agents for tumor diagnosis and synergistic cancer therapy.