The combination of in situ photodynamic promotion and ion-interference to improve the efficacy of cancer therapy

Photodynamic therapy (PDT) is proved to be a promising modality for clinical cancer treatment. However, it also suffers from a key obstacle in association with its oxygen-dependent nature which greatly limits its effective application against hypoxic tumors. Herein, on the basis of the unique property of calcium peroxide (CaO 2 ), we propose an O 2 -self-supply strategy for the promotion of PDT by combining the in situ O 2 -generation characteristic of calcium peroxide with the photosensitive nature of porphyrin . A shell of ZIF-8 was synthesized surround the CaO 2 core to prevent the CaO 2 from premature decomposition and increased the loading of THPP efficiently. Depending on the in situ self-supply of O 2 , the photosensitizer was able to exhibit an enhanced PDT effect that significantly inhibit the growth of tumor. Moreover, the enrichment of free calcium ions derived from the decomposition of CaO 2 under acidic tumor microenvironment also shows the unique ion-interference effect and contributes to the obvious inhibition against tumor growth. This work presents a synergistic strategy for the construction of a photodynamic promotion/ion-interference combined nano-platform which can also serve as an inspiration for the future design of effective nanocomposites in tumor treatment.