MnO₂ doped graphene nanosheets for carotid body tumor combination therapy

Combination therapy is a cornerstone of tumor therapy, which can make up for the shortcomings of a single treatment and improve the cure rate of cancer. Near infrared induced therapy is widely applied owing to good accessibility, safety profile, and a wide range of effectiveness. Here, we use reduced nanographene oxide (rNGO) sheets with MnO₂ nanoparticles as a photothermal agent to trigger further photodynamic therapy and chemotherapy. Doxorubicin (DOX, chemotherapeutic agent) and methyl blue (MB, photosensitizer) are loaded onto graphene oxide through a strong physical bond and rapidly released under high temperature. Besides, MnO₂ nanoparticles can catalyze hydrogen peroxide inside of tumor and produce oxygen as a raw material for photodynamic therapy. In vitro experiments illustrated an effective ablation of PC-12 cells by rGO@MnO₂/MB/Dox incubation combined with 808 nm near-infrared (NIR) laser radiation. For in vivo experiments in a model of carotid body tumor, rGO@MnO₂/MB/Dox was locally injected, followed by 808 nm NIR laser irradiation. We found that the number of tumor cells was significantly reduced, the tumor volume was reduced, and there were no side effects. This may provide a new idea for the combination treatment of carotid body tumor.