Preparation of doxorubicin-loaded porous iron Oxide@ polydopamine nanocomposites for MR imaging and synergistic photothermal–chemotherapy of cancer

• A biosafe multifunctional PION@PDA-PEG nanocomposite was developed. • The prepared nanocomposite permitted remarkable drug loading capacity. • Excellent MRI contrast agent capability was achieved by the high surface area of PION. • The release of DOX from nanocomposites could be triggered by NIR laser irradiation. • Cancer therapeutic efficacy was improved by synergistic photothermal-chemotherapy. Recently, the development of biosafe nanocomposites with integrated diagnosis and therapeutic modality is received great attention in anti-cancer drug delivery. In this sturdy, we developed a multifunctional PION@PDA-PEG nanocomposite that combines the functions of magnetic resonance (MR) imaging, photothermal therapy (PTT) and chemotherapy into one single nanoprobe. The spherical and uniform-sized porous iron oxide nanoparticles (PION) were synthesized via a simple solvothermal method. Subsequently, a near-infrared light (NIR) sensitive polydopamine (PDA) shell was directly coated on the surface of PIONs to form monodisperse and biosafe core-shell nanocomposites, Thereafter, the surface of nanocomposites was further modified with polyethylene glycol (PEG) to prolong their blood circulation lifetime. The prepared PION@PDA-PEG showed excellent biocompatibility and promising MR imaging contrast agent capability. Furthermore, the porous structure of PION and the abundant functional groups of PDA shell permitted the remarkable drug loading capacity of more than 24.1 wt%. In addition, the synergistic photothermal- chemotherapy exhibited obvious enhanced anti-tumor effect in in-vitro cell experiment. These results suggest that the developed PION@PDA-PEG nanocomposite can be utilized as an efficient drug nanocarrier for biomedical applications including MR imaging and photothermal-chemotherapy.