Synthesis of polyacrylic acid-coated AuPd@FexOy nanoparticles for synergistic chemodynamic and photothermal therapy of osteosarcoma†

The treatment outcomes of osteosarcoma (OS) can be improved significantly by multimodal synergistic therapy. In this report, polyacrylic acid-coated AuPd@Fe_xO_y core@shell nanoparticles (termed as PAA-AuPd@Fe_xO_y NPs) have been synthesized for magnetic resonance imaging (MRI)-guided synergistic chemodynamic therapy and photothermal therapy (CDT–PTT) of OS through a simple two-step process, which includes synthesis of AuPd@Fe_xO_y NPs by a self-assembly redox strategy, and coating PAA on the AuPd@Fe_xO_y NP surface by physical adsorption. The amorphous Fe_xO_y shell of the PAA-AuPd@Fe_xO_y NPs not only exhibits a pH-responsive T₁-weighted MRI contrast ability, but also can generate a large number of hydroxyl radicals (˙OH) by the glutathione (GSH) amplified Fenton reaction. Furthermore, the production of reactive oxygen species (ROS) can be enhanced by 808 nm near infrared (NIR) laser irradiation because the PAA-AuPd@Fe_xO_y NPs exhibit excellent photothermal conversion capability. The features of PAA-AuPd@Fe_xO_y NPs improve the tumour-MRI sensitivity, and facilitate synergistic CDT–PTT of tumours. The growth of MG63 OS in a mouse model is effectively suppressed by the PAA-AuPd@Fe_xO_y NPs with 808 nm NIR laser irradiation.