Preparation of Dextran- and Carboxymethyl Dextran–Coated Fe₃O₄ Nanoparticles for Breast Cancer Cell Labeling and Magnetic Hyperthermia

Breast cancer is one of the deadliest cancers for women, so cell labeling and therapy of breast cancer become imperative. In this work, dextran- and carboxymethyl dextran–coated Fe₃O₄ nanoparticles (Fe₃O₄@DEX and Fe₃O₄@CMD) were well synthesized through the co-precipitation method. The dextran and carboxymethyl dextran coating reduces the average particle size of Fe₃O₄ nanoparticles from 10.9 to 4.0–5.5 nm, and the coated samples exhibit average hydrodynamic diameters ranging from 31 to 110 nm. The coating promotes the dispersibility of nanoparticles. Saturation magnetization is reduced from 60.3 to 5.6–7.1 emu/g in the coated MNPs due to the large weight ratio of the coating layer and the decrease in particle size. Hemolysis and cytotoxicity assay results indicate the excellent biocompatibility of Fe₃O₄ nanoparticles. The cellular uptake assay confirms that both dextran- and carboxymethyl dextran–coated Fe₃O₄ nanoparticles are easily taken in by breast cancer cells. Comprehensively considering dispersion, biocompatibility, and cellular uptake, the Fe₃O₄@CMD is more suitable for application in the bio-labeling of breast cancer cells. The SAR values of the Fe₃O₄@DEX and Fe₃O₄@CMD range from 19.2 to 30.7 W/g. The SAR value is mainly influenced by the hydrodynamic diameter in the coated samples. The Fe₃O₄@CMD20 shows the maximum SAR value of 30.7 W/g and has potential application in magnetic hyperthermia therapy.