Remotely controlled drug release based on iron oxide nanoparticles for specific therapy of cancer

Chemotherapy has been widely used in clinic and usually causes serious side effects. To improve therapeutic effect, it is really necessary to realize local drug release and specific therapy. In this work, we demonstrate Azo (4,4-azobis (4-cyanovaleric acid))-functionalized multifunctional nanoparticles to realize near-infrared (NIR) laser-responsive drug release and combined chemo-photothermal cancer therapy. Doxorubicin (DOX) was attached to magnetic nanoparticles via a thermal-cleavable Azo linker, which could decompose while the temperature reach ∼43°C. The Azo-functioned Fe₃O₄ NPs also showed good capability as a contrast for T₂-weighted magnetic resonance (MR) images in vivo. After intravenous injection, the Fe₃O₄-Azo NPs could targeted accumulate in the tumor. Once exposed to NIR irradiation, Fe₃O₄ nanoparticles (NPs) absorb NIR light to generate heat rapidly, resulting in the tumor specific DOX release and remarkable tumor growth inhibition effect. The Azo-functionalized Fe₃O₄ NPs with multifunction of in vivo imaging and combined therapy present a potential for tumor diagnosis treatment.