Preparation of drug-loaded iridium oxidenanocomposites and its application in synergetic sonodynamic/chemotherapeutic therapy against cancer

Objective To prepare iridium oxide (IrOX) as a nano-sonosensitizer to load chemotherapy drug doxorubicin (DOX) in order to obtain nanocomposites IrOX@DOX with dual response of pH/ultrasound (US) irradiation, and to verify its efficacy in sonodynamic therapy (SDT)-chemotherapy for tumor treatment. Methods IrOX nanoparticles were prepared by thermal hydrolysis and then loaded with DOX. The morphological, chemical and physical properties of the nanoparticles were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectrophotometer (UV-Vis) and Zeta potential analyzer. The drug loading efficiency and drug release behavior were determined with UV-vis spectrometry and ELISA. The generation of reactive oxygen species (ROS) by IrOX@DOX nanoparticles was evaluated usingelectron spin-resonance spectroscopy (ESR). The uptake of IrOX@DOX by 4T1 cells under ultrasonic irradiation was evaluated with laser confocal scanning microscopy (LCSM), and the level of