Polymer-coated cobalt ferrite nanoparticles: synthesis, characterization, and toxicity for hyperthermia applications

Monodispersed CoFe2O4 nanoparticles were synthesized by the thermal decomposition of Co and Fe acetylacetonate in octadecene, which contained oleic acid (OA) and oleylamine (OLA). The hydrophobicity of the CoFe2O4 nanoparticles was alleviated such that they were water dispersible by encapsulating them with poly(maleic anhydride-alt-1-octadecene) (PMAO). The heating ability of these magnetic fluids was assessed by calorimetry measurement of specific absorption rate under an alternating magnetic field of 300 Oe within the frequency interval of 290–450 kHz. The highest value of the specific absorption rate was 297.4 W g−1 for a sample concentration of 1 mg mL−1 under an applied field of 300 Oe and frequency of 450 kHz. Linear response theory was used to explain the results. The high specific absorption rate of the nanofluid based on PMAO-encapsulated CoFe2O4@OA/OLA showed that it may meet the requirements for practical applications in tumor-targeted hyperthermia treatment. In vitro cytotoxicity analysis was also performed on Sarcoma 180 cancer cells, and the results showed that these nanoparticles were nontoxic to cells.