Advanced Institute for Material Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Dalton Trans. 2011 Feb 7;40(5):1073-8. doi: 10.1039/c0dt01280g. Epub 2010 Dec 16.
Magnetic nanoparticles (MNPs) have many potential biomedical applications. Improvements in their magnetic properties and solubility are necessary for these applications to realize their full potential. In this study, MNPs in the form of raspberry-like magnetite (Fe(3)O(4)) nanoparticle clusters, consisting of tiny Fe(3)O(4) particles with a diameter of approximately 20 nm, were prepared under hydrothermal conditions at 200 °C in the presence of 3,4-dihydroxyhydroxysinnamic acid (DHCA). The primary particles were connected by DHCA molecules to form the clusters, which were well dispersed in water media because a COOH group from DHCA appeared on their surfaces. The cluster size could be tuned from 50 to 400 nm without changing the primary particle size by controlling the reaction time. Therefore, all prepared clusters displayed superparamagnetic properties at room temperature. In addition, the sensitivity of Fe(3)O(4) to an external magnetic field could also be controlled by the cluster size.
磁性纳米粒子（MNPs）在许多生物医学领域都有潜在的应用。为了实现这些应用的全部潜力，需要改善它们的磁性能和溶解度。在这项研究中，在 200°C 的水热条件下，以 3,4-二羟基肉桂酸（DHCA）作为稳定剂，制备了具有类覆盆子状结构的磁铁矿（Fe3O4）纳米粒子簇的 MNPs。这些纳米粒子簇由直径约为 20nm 的微小 Fe3O4 粒子通过 DHCA 分子连接而成，由于 DHCA 分子上的一个 COOH 基团出现在其表面，因此它们在水介质中很好地分散。通过控制反应时间，可以将簇的尺寸从 50nm 调至 400nm，而不改变初级粒子的尺寸。因此，所有制备的簇在室温下均表现出超顺磁性。此外，通过控制簇的尺寸还可以控制 Fe3O4 对外磁场的敏感性。
