A modified method of dextran-coated Fe_3O_4 magnetic nanoparticles by one-step and two-step synthetic pathways

Dextran coated magnetic nanoparticles (dextran@ MNPs) have been studied in the field of hyperthermia. The characteristics of dextran coated magnetic nanoparticles, such as particle size and specific adsorption rate, can be affected by synthesis technique. In this study, we synthesized dextran@MNPs with one-step method and two-step method. The major difference between these methods is that two-step synthesis method has dextran existing in the synthesis of Fe_3O_4 MNPs. The complexes derived from the two methods were examined by X-ray diffraction, superconducting quantum interference device magnetometer and scanning electron microscope. The saturation magnetization values and specific adsorption rate (SAR) were investigated carefully. For MNPs, the values were 4.3 emu/g and 50.2±5.9 W/g, respectively; and those for dextran@MNPs (one-step and two-step synthetic samples) were approximate 3.0 emu/g and 40.9 ± 6.7 W/g, 48.1±7.2 W/g, respectively. The dextran@ MNPs by one-step synthesis method had less saturation magnetization values and worse heating efficiency. The particle sizes of the dextran@ MNPs synthesized with one-step pathway is 9.3 ± 1.8 nm; and those with the two-step route is 20.3 ± 3.7 nm. Our study demonstrates a modified method for dextran@ MNPs which results in better characteristics.