Coordination bonding-based Fe3O4@PDA-Zn2+-doxorubicin nanoparticles for tumor chemo-photothermal therapy

Multistimuli-responsive vehicles that deliver drugs in temporal-, spatial- and dosage-controlled manners have developed as a potential platform in tumor therapy. However, how to integrate these functions in one single carrier effectively still presents a lot of challenge. Here, we developed a strategy to construct a photothermal and pH responsive platform based on Zn2+ coordination with doxorubicin (DOX) and polydopamine (PDA) on the surface of magnetic nanoparticles (Fe3O4@PDA-Zn2+-DOX NPs). In this architecture, Fe3O4@PDA nanoparticles triggered photothermal effects for tumor hyperthermia, and Zn2+ coordinated DOX was released in responding to the thermal effect to achieve chemotherapy simultaneously. Moreover, DOX release was further promoted at acidic environment due to the pH sensitivity of Zn2+ coordination. Therefore, our system possesses multiple effects in tumor treatment: photothermal therapy with near infrared lighting (NIR), thermosensitive DOX release for chemotherapy, and pH-responsive DOX release to enhance deeper therapy in tumor acidic microenvironment. Our in vivo results provide the evidence that Fe3O4@PDA-Zn2+-DOX NPs upon laser exposure have effective anti-tumor therapeutic activity, indicating this platform is suitable for enhanced chemo-photothermal synergistic tumor therapy.