Heat-Generating Iron Oxide Multigranule Nanoclusters for Enhancing Hyperthermic Efficacy in Tumor Treatment

The development of heat-generating magnetic nanostructures is critical for the effective management of tumors using magnetic hyperthermia. Herein, we demonstrate that polyethylene glycol (PEG)-coated iron oxide (magnetite, Fe 3 O 4 ) multigranule nanoclusters (PEG-MGNCs) can enhance the efficiency of hyperthermia-based tumor suppression in vitro and in vivo . MGNCs consisting of granules (crystallites) measuring 22.9 nm in diameter were prepared via the hydrothermal polyol method, followed by the surface modification of MGNCs with PEG-dopamine. The freshly prepared PEG-MGNCs exhibit 145.9 ± 10.2 nm diameter on average under aqueous conditions. The three-dimensional structures of PEG-MGNCs enhance the hyperthermic efficacy compared with PEGylated single iron-oxide nanoparticles (NPs), resulting in severe heat damage to tumor cells in vitro . In the SCC7 tumor-bearing mice, near-infrared f…