Flame spray pyrolyzed carbon-encapsulated Au/Fe3O4 nanoaggregates enabled efficient photothermal therapy and magnetic hyperthermia of esophageal cancer cells

Multifunctional magneto-plasmonic nanoparticles with magnetic hyperthermia and photothermal therapy could kill cancer cells efficiently. Herein, carbon-encapsulated Au/Fe 3 O 4 (Au/Fe 3 O 4 @C) was fabricated using an enclosed flame spray pyrolysis. The nanostructures, including an Fe 3 O 4 core (51.9–55.2 nm) with a decreasing carbon shell thickness and an Au core (4.68–8.75 nm) coated with 2–4 graphite layers, were tailored by tuning the C 2 H 4 content in the reacting gas mixture. Saturation magnetization (33.7–48.2 emu/g) and optical absorption were determined. The carbon shell facilitated the dispersion of Au/Fe 3 O 4 and restrained their laser-induced and magnetic field-induced coalescence and growth. Au/Fe 3 O 4 @C exhibited excellent magnetic resonance imaging capability (91.4 mM −1 s −1 ) and photothermal performance (65.4°C for 0.8 mg/mL Au/Fe 3 O 4 @C at a power density of 1.0 W/cm 2 after 300 s near-IR laser irradiation (808 nm)). Moreover, the combined application of photothermal and magnetic-heating properties reduced the required intensity of both laser and magnetic field compared to the intensity of separate situations. Our work provides a unique, intriguing approach to preparing multicomponent core/shell nanoaggregates that are promising candidates for esophageal cancer cell therapy.