Photothermal/sonodynamic therapy of melanoma tumor by a gold/manganese dioxide nanocomposite: In vitro and in vivo studies

Nanosized materials have favorable applications in nanomedicine including photothermal therapy (PTT) and sonodynamic therapy (SDT) of most malignancies. Since conventional methods of cancer treatment encounter limitations, development of other efficient routes is quite necessary. In this study, a gold/manganese dioxide nanocomposite (Au/MnO2 NC) was synthesized as a novel photo- and sono- responsive nanomaterial that was activated upon laser light of 808-nm wavelength irradiation or ultrasound exposure for cancer treatment applications. The synthesized nanocomposite comprised gold nanoparticles of about 125 +/- 66 nm in diameter adhered to manganese dioxide nanoroads of 77 +/- 30 nm in diameter and up to 2 mu m length. Au/MnO2 NC represented a very good photothermal and sonodynamic conversion ability. Cytotoxicity of Au/MnO2 NC toward the C540 (B16/F10) cell line was evaluated through thermal ablation and reactive oxygen species (ROS) generation upon phototherapy and sonotherapy, respectively. Intratumoral injection of a low-dose of Au/MnO2 NC into a melanoma tumor-bearing animal model followed by laser and ultrasound radiation led to necrosis in the tumor tissue. The findings revealed that Au/MnO2 NC is aphotosensitizer/sonosensitizer for PTT and SDT of cancer.