α-Fe Nanoparticles and Multiwalled Carbon Nanotubes Composite with Improved Photothermal Conversion Efficiency for Tumor Therapy

The efficiency of photothermal therapy based on conventional Fe3O4 nanoparticles (NPs) is limited due to their low absorption in the near-infrared (NIR) region. To surmount this obstacle, α-Fe nanoparticles/multiwalled carbon nanotubes (MWCNTs) composite is synthesized by incipient wetness impregnation (IWI). Due to improved extinction and heat generation mechanism (plasmons/electrons thermalization) of metallic Fe NPs with in nanocomposite structure, the photothermal conversion efficiency of Fe/MWCNTs composite is 87.98% (content: 60 μg/mL, 808 nm at power density of 1 W/cm2), which is highest among the previously reported Fe3O4 and other carbon-based nanostructures. The HaCaT cell viability after 72 h of coculturing is more than 91%, indicating the good biocompatibility of nanocomposite. The viability of B16–F10 melanoma cells is only 9.78% (808 nm laser irradiation for 15 min at 0.33 W/cm2), demonstrating the potential for hands-on applications.