Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan.
J Biomater Appl. 2011 Mar;25(7):643-61. doi: 10.1177/0885328209351136. Epub 2010 Mar 5.
Magnetic iron oxide nanoparticles (MIONPs) were synthesized in a FeCl₂-NaNO₃-NaOH aqueous system under various initial Fe(2+)/NO⁻₃ molar ratios (α) and Fe(2+)/OH- molar ratios (β) in order to clarify the effects of the initial molar ratio of reactants on the reaction mechanism. The Fe(2+)/NO⁻₃ /OH(-) molar ratio of 3 : 1 : 5 led to the formation of magnetic nanoparticles mainly composed of magnetite (Fe₃O₄) and maghemite (γ-Fe₂O₃). The 36 nm sized γ-Fe₂O₃ and 413 nm sized Fe₃O₄ were obtained by changing the order in which NaNO₃ was added to a NaOH solution. The in vitro heat generations of the resulting MIONPs in an agar phantom were measured under an alternating magnetic field (100 kHz, 23.9 kA/m). The temperature rise (ΔT) of the agar phantom for the 36 nm sized γ-Fe₂O₃ was 55°C in the first 140 s, with a concentration of 58 mg Fe/mL. Our results showed that it is possible to prepare MIONPs with high heating efficiencies under optimal conditions using the present method.
磁性氧化铁纳米粒子（MIONPs）在 FeCl₂-NaNO₃-NaOH 水溶液体系中通过不同的初始 Fe(2+)/NO⁻₃摩尔比（α）和 Fe(2+)/OH-摩尔比（β）进行合成，以阐明反应物初始摩尔比对反应机制的影响。Fe(2+)/NO⁻₃ /OH(-)摩尔比为 3:1:5 时，主要生成由磁铁矿（Fe₃O₄）和磁赤铁矿（γ-Fe₂O₃）组成的磁性纳米粒子。通过改变 NaNO₃加入 NaOH 溶液的顺序，得到了 36nm 大小的γ-Fe₂O₃和 413nm 大小的 Fe₃O₄。在琼脂体模中，对所得 MIONPs 在交变磁场（100kHz，23.9kA/m）下的体外发热进行了测量。在最初的 140s 内，浓度为 58mg Fe/mL 的 36nm 大小的γ-Fe₂O₃的琼脂体模的温升（ΔT）为 55°C。结果表明，在优化条件下，使用本方法可以制备出具有高热效率的 MIONPs。
