Widdrat Marc, Kumari Monika, Tompa Éva, Pósfai Mihály, Hirt Ann M, Faivre Damien
Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Science Park Golm 14424 Potsdam (Germany), /567-9402 E-mail:
Institute of Geophysics, ETH-Zürich Sonneggstrasse 5, CH-8092 Zürich (Switzerland).
Chempluschem. 2014 Aug;79(8):1225-1233. doi: 10.1002/cplu.201402032. Epub 2014 Jul 17.
Magnetite is an iron oxide found in rocks. Its magnetic properties are used for paleoclimatic reconstructions. It can also be synthesized in the laboratory to exploit its magnetic properties for bio- and nanotechnological applications. However, although the magnetic properties depend on particle size in a well-understood manner, they also depend on the structure of the oxide, because magnetite oxidizes to maghemite under environmental conditions. The dynamics of this process have not been well described. Here, a study of the alteration of magnetite particles of different sizes as a function of their storage conditions is presented. Smaller nanoparticles are shown to oxidize more rapidly than larger ones, and that the lower the storage temperature, the lower the measured oxidation. In addition, the magnetic properties of the altered particles are not decreased dramatically, thus suggesting that this alteration will not impact the use of such nanoparticles as medical carriers.
磁铁矿是一种存在于岩石中的氧化铁。其磁性特性被用于古气候重建。它也可以在实验室中合成，以利用其磁性特性用于生物和纳米技术应用。然而，尽管磁性特性以一种广为人知的方式取决于颗粒大小，但它们也取决于氧化物的结构，因为磁铁矿在环境条件下会氧化成磁赤铁矿。这个过程的动力学尚未得到很好的描述。在此，展示了一项关于不同大小磁铁矿颗粒随储存条件变化的研究。结果表明，较小的纳米颗粒比较大的纳米颗粒氧化得更快，并且储存温度越低，测得的氧化程度越低。此外，发生变化的颗粒的磁性特性并没有显著降低，因此表明这种变化不会影响此类纳米颗粒作为医学载体的用途。
