Macrophages Loaded with Fe Nanoparticles for Enhanced Photothermal Ablation of Tumors.

Magnetic iron nanoparticle-based theranostics agents have attracted much attention due to their good magnetism and biocompatibility. However, efficiently enriching tumors with iron nanoparticles to enhance the treatment effect remains a pressing challenge. Herein, based on the targeting and high phagocytosis of macrophages, an Fe nanoparticle-loaded macrophage delivery system was designed and constructed to efficiently deliver iron nanoparticles to tumors. Hydrophilic Fe@Fe 3 O 4 nanoparticles with a core-shell structure were synthesized by pyrolysis and ligand exchange strategy. Subsequently, they were loaded into macrophages (RAW264.7 cells) using a co-incubation method. After loading into RAW264.7, the photothermal performance of Fe@Fe 3 O 4 nanoparticles were significantly enhanced. In addition, Fe@Fe 3 O 4 nanoparticles loaded into the macrophage RAW264.7 (Fe@Fe 3 O 4 @RAW) exhibited a good T 2 -weighted MRI contrast effect and clear tumor imaging in vivo due to the tumor targeting tendency of macrophages. More importantly, after being intravenously injected with Fe@Fe 3 O 4 @RAW and subjected to laser irradiation, the tumor growth was effectively inhibited, indicating that macrophage loading could enhance the tumor photothermal ablation ability of Fe@Fe 3 O 4 . The macrophage mediated delivery strategy for Fe@Fe 3 O 4 nanoparticles was able to enhance the treatment effect, and has great potential in tumor theranostics.