Synthesis of cobalt ferrite nanoparticles using spermine and their effect on death in human breast cancer cells under an alternating magnetic field

•Cobalt ferrite nanoparticles (diameter: ∼10 nm) were synthesized using spermine.•Uptake of cobalt ferrite nanoparticles into breast cancer MCF-7 cells was observed.•Simple addition of cobalt ferrite nanoparticles did not induce MCF-7 cell death.•MCF-7 cell death was induced by cobalt ferrite under an AC magnetic field.

To compare heat generation under an AC magnetic field for inducing cancer cell death, CoFe2O4 and Fe3O4 nanoparticles with a diameter of ∼10 nm were synthesized by hydrolysis in an aqueous solution containing the metal chlorides iron(III) chloride and cobalt(II) or iron(II) chloride, with spermine or N,N'-bis(3-aminopropyl)butane-1,4-diamine, as a base and a protective reagent. Both CoFe2O4 and Fe3O4 nanoparticles were incorporated into human breast cancer MCF-7 cells; the nanoparticles exhibited little toxicity on the cells. When the cells containing nanoparticles were subjected to an AC magnetic field, MCF-7 cell death was induced by heat generated from ∼10-nm CoFe2O4 nanoparticles but not from ∼10-nm Fe3O4 nanoparticles. An increase in coercivity derived from the substitution of Fe2+ with Co2+ facilitated the ability of the nanoparticles to induce cell death in human breast cancer cells under an AC magnetic field.

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