Fabrication of multifunctional ferric oxide nanoparticles for tumor-targeted magnetic resonance imaging and precise photothermal therapy with magnetic field enhancement†
In this study, a biocompatible nanotheranostic platform (termed as Fe2O3@PDA-affibody) has been constructed on the basis of coating a near-infrared light (NIR)-absorbing polydopamine (PDA) shell on oleic acid-capped superparamagnetic ferric oxide nanoparticles (Fe2O3 NPs) using the water-in-oil microemulsion method and then conjugated with affibody ZIGF1R:4551, a peptide with high affinity to tumor and a polyethylene glycol (PEG) stabilizer. The Fe2O3@PDA-affibody integrates T2-weighted magnetic resonance imaging (MRI), tumor-targeting, and magnetic field (MF)-enhanced photothermal therapy (PTT) functionalities into an all-in-one system. The Fe2O3@PDA-affibody shows high negative contrast in the MRI of an SW620 tumor bearing mouse with a decrease of 68% MRI signal, indicating that the Fe2O3@PDA-affibody can recognize tumor with high efficacy and specificity. Furthermore, a high accumulation ratio (>13.5% ID g−1) and enhanced inhibition of tumor growth are achieved under near-infrared (NIR) (808 nm) laser irradiation with the aid of an external MF focused on the targeted tumor, resulting in complete eradication of mouse-borne SW620 tumors without regrowth.