MoS2 Nanocomposites Loaded with Zinc Phthalocyanine for NIR Light-Triggered Photothermal/Photodynamic Therapy of Breast Cancer

In recent years, photothermal (PTT) and photodynamic (PDT) therapy has become an important tumor treatment in the biomedical field due to its advantages of less side effects and higher targeting selectivity. However, the inherent toxicity of the formulations, poor biocompatibility, and long treatment cycle of monotherapy hinder their further clinical application. In this study, molybdenum disulfide nanosheets prepared by a hydrothermal method were used as a photothermal agent to enhance its biocompatibility by surface modification of bovine serum albumin (BSA). Afterward, the photosensitizer zinc phthalocyanine (ZnPc) and the target recognition molecule folic acid (FA) were sequentially loaded on the MoS2-BSA surface with the aid of hydrophobicity to obtain ZnPc-loaded MoS2 nanocomposites that possessed both the PTT/PDT performance and targeted binding to the folate receptor in tumor cells (FA-ZnPc-BSA/MoS2). The results of in vitro experiments, such as cytotoxicity and hemolysis, showed that the FA-ZnPc-BSA/MoS2 nanocomplexes possessed significant temperature-raising ability, good warming-cooling stability, and hemocompatibility and were of low cytotoxicity. The 808 nm near-infrared (NIR) laser-induced temperature increase and singlet oxygen generated by a FA-ZnPc-BSA/MoS2 nanocomplex in and outside breast cancer cells destroyed mitochondria and then induced apoptosis of tumor cells. The results of the FA-ZnPc-BSA/MoS2 nanocomposite PTT/PDT combined treatment on breast cancer tumor-bearing mice showed that the treatment time of 14 days was not only effective in ablating subcutaneous tumor tissue but also showed no signs of recurrence. The weight of tumor-bearing mice also increased steadily during treatment, and the five major organs of mice showed no obvious damage. The FA-ZnPc-BSA/MoS2 nanocomplex injected into the tail vein was basically metabolized out of the body within 7 days. In conclusion, the MoS2 nanocomposite loaded with ZnPc is a safe nanotherapeutic agent and has the potential to be used in PTT/PDT targeted synergistic therapy of tumor cells.