A Cu₉S₅ nanoparticle-based CpG delivery system for synergistic photothermal-, photodynamic- and immunotherapy

Despite its great potential in cancer therapy, phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT), often cause metastasis of tumors. Immunotherapy has revolutionized the cancer treatment owing to the capability of activating immune system to eliminate tumors. However, the integration of phototherapy and immunotherapy in a single nanoagent for cancer therapy is still a challenging task. Here, we fabricated (Cu₉S₅@mSiO₂-PpIX@MnO₂@CpG (CSPM@CpG)) as a synergistic therapeutic model for phototherapy enhanced immunotherapy. The intracellular uptake of cytosine-phosphate-guanine (CpG) promoted the infiltration of cytotoxic T lymphocytes (CTLs) in tumor tissue, further stimulating the production of interferon gamma (IFN-γ) and remarkably elevating the immune response level. Excellent anti-tumor effects have been achieved by synergistic PTT/PDT/immunotherapy. The metastasis of tumors was effectively inhibited by the immune response of CpG. Thus, our proposed work provides a strategy to combine phototherapy with immunotherapy to enhance the therapeutic efficiency and further inhibit metastasis of tumors.