Armijo Leisha M, Brandt Yekaterina I, Mathew Dimple, Yadav Surabhi, Maestas Salomon, Rivera Antonio C, Cook Nathaniel C, Withers Nathan J, Smolyakov Gennady A, Adolphi Natalie L, Monson Todd C, Huber Dale L, Smyth Hugh D C, Osiński Marek
Center for High Technology Materials, 1313 Goddard SE, University of New Mexico, Albuquerque, NM 87106, USA.
Department of Biochemistry and Molecular Biology, Health Sciences Center, University of New Mexico, Albuquerque, NM 87131, USA.
Nanomaterials (Basel). 2012 May 7;2(2):134-146. doi: 10.3390/nano2020134.
Magnetic nanocrystals have been investigated extensively in the past several years for several potential applications, such as information technology, MRI contrast agents, and for drug conjugation and delivery. A specific property of interest in biomedicine is magnetic hyperthermia-an increase in temperature resulting from the thermal energy released by magnetic nanocrystals in an external alternating magnetic field. Iron oxide nanocrystals of various sizes and morphologies were synthesized and tested for specific losses (heating power) using frequencies of 111.1 kHz and 629.2 kHz, and corresponding magnetic field strengths of 9 and 25 mT. Polymorphous nanocrystals as well as spherical nanocrystals and nanowires in paramagnetic to ferromagnetic size range exhibited good heating power. A remarkable 30 °C temperature increase was observed in a nanowire sample at 111 kHz and magnetic field of 25 mT (19.6 kA/m), which is very close to the typical values of 100 kHz and 20 mT used in medical treatments.
在过去几年中，磁性纳米晶体因其在信息技术、磁共振成像（MRI）造影剂以及药物偶联与递送等多种潜在应用而受到广泛研究。生物医学领域感兴趣的一个特定特性是磁热疗——磁性纳米晶体在外部交变磁场中释放的热能导致温度升高。合成了各种尺寸和形态的氧化铁纳米晶体，并使用111.1 kHz和629.2 kHz的频率以及相应9和25 mT的磁场强度对其比损耗（加热功率）进行测试。顺磁性到铁磁性尺寸范围内的多晶纳米晶体以及球形纳米晶体和纳米线均表现出良好的加热功率。在111 kHz和25 mT（19.6 kA/m）的磁场下，纳米线样品中观察到温度显著升高30°C，这非常接近医疗中使用的100 kHz和20 mT的典型值。
