2009 Volume 34 Issue 1 Pages 77-80
Size-controlled magnetite nanoparticles (MNP) with several dozen to several hundred of nanometers (nm) were prepared for hyperthermia of cancer. Nanoparticles of single-phase magnetite, as revealed by X-ray diffraction and magnetic property measurement, were synthesized by mean of an oxidation-precipitation method with iron (II) chloride as starting materials, which was oxidized to ferric salts by sodium nitrate (NaNO3) in an N2-deaerated sodium hydroxide (NaOH) aqueous solution. The particles size was controlled by adjusting the concentration of the reactant and the addition order of NaNO3. The resulting MNP had an average diameter ranging from 24 nm to 413 nm and their in vitro heat generations were measured in agar phantom under an alternating magnetic field (100 kHz, 23.9 kAm-1). Temperature rise in the agar phantom for MNP 24 nm in size was ΔT =55 ℃ in 30 second at a MNP concentration of 58 mg Fe ml-1. For MNP larger than 24 nm, heat generation decreased as particle size increased. Hysteresis loss mainly contributed the heat-generating mechanism. It is believed that MNP 24 nm in size is useful for in situ hyperthermia treatment of cancer.
