Advances in medicine are bringing about safer and more effective cancer treatment therapies. Magnetic fluid hyperthermia (MNFH) agents have low side effects and high treatment efficacy compared to conventional chemotherapy or radiotherapy treatments. However, biocompatibility remains a critical challenge for their successful clinical application.

In their communication in Advanced Materials, Professor Seongtae Bae and co-workers from the University of South Carolina, Seoul National University College of Medicine, Yokohama National University, and Augusta University develop a highly biocompatible superparamagnetic nanoparticle MNFH agent that shows promising hyperthermia effects to completely eradicate tumors.

Magnesium shallow-doped iron oxide (Mg_0.13-γFe₂O₃) superparamagnetic nanoparticles (SPNPs) were synthesized using a thermal decomposition method. Magnesium acetate and iron(III) acetylacetonate metal precursors were mixed in the presence of oleic acid and organic solvent, and heated under a bubbling oxygen/argon gas mixture. By varying the initial molar ratio of the metal precursor, the Mg²⁺ doping concentration and distribution were systematically varied from 0 to 0.15 at%.

SPNPs where Mg²⁺ occupies ≈50 % of Fe vacancies have the highest DC saturation magnetic moment and AC magnetic susceptibility.  At low AC magnetic field, SPNPs show an exceptionally high maximum AC heating temperature of 180 °C compared to 22 °C for MgFe₂O₄ SPNPs, and a higher magnetic susceptibility compared to MgFe₂O₄ and Fe₃O₄.

The SPNPs were then coated with methoxy-polyethyleneglycol-silane (PEG) to form nanofluids. Hep3B cells transfected with luciferase were grown subcutaneously in mice and 100 µL of SPNP nanofluid was intratumorally injected into the tumor, and the mice were placed in an AC magnetic coil and exposed to an AC magnetic field for 900 s. The temperature of Hep3B injected with SPNP nanofluids rapidly increased and saturated at ≈50.2 °C. After two days, Hep3B-induced tumors treated by the nanofluids showed no bioluminescent activity, indicating that the cancer was completely necrotized by magnetic nanofluid hyperthermia using the SPNP nanofluids.

To find out more about this superparamagnetic-nanoparticles-based hyperthermia agent, please visit the Advanced Materials homepage.