Synthesis of polyacrylic acid-coated AuPd@Fe_<i>x</i>O_<i>y</i> 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_<i>x</i>O_<i>y</i> core@shell nanoparticles (termed as PAA-AuPd@Fe_<i>x</i>O_<i>y</i> 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_<i>x</i>O_<i>y</i> NPs by a self-assembly redox strategy, and coating PAA on the AuPd@Fe_<i>x</i>O_<i>y</i> NP surface by physical adsorption. The amorphous Fe_<i>x</i>O_<i>y</i> shell of the PAA-AuPd@Fe_<i>x</i>O_<i>y</i> NPs not only exhibits a pH-responsive <i>T</i>₁-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_<i>x</i>O_<i>y</i> NPs exhibit excellent photothermal conversion capability. The features of PAA-AuPd@Fe_<i>x</i>O_<i>y</i> 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_<i>x</i>O_<i>y</i> NPs with 808 nm NIR laser irradiation.