Department of Experimental Physics, Institute of Physics and Technology, Ural Federal University, Ekaterinburg 620002, Russian Federation.
Centre for Energy Research, Konkoly-Thege Miklós út. 29-33, 1121 Budapest, Hungary; Institute of Environmental Sciences, University of Pannonia, H-8200 Veszprém, Egyetem út. 10, Hungary.
J Inorg Biochem. 2020 Dec;213:111202. doi: 10.1016/j.jinorgbio.2020.111202. Epub 2020 Jul 25.
Iron(III)-polymaltose pharmaceutical ferritin analogue Ferrifol® was investigated by high resolution transmission electron microscopy (HRTEM), X-ray diffraction, thermogravimetry, electron magnetic resonance (EMR) spectroscopy, direct current magnetization measurements and Fe Mössbauer spectroscopy to get novel information about the structural arrangement of the iron core. The Ferrifol® Mössbauer spectra measured in the range from 295 K to 90 K demonstrated non-Lorentzian two-peak pattern. These spectra were better fitted using a superposition of 5 quadrupole doublets with the same line width. The obtained Mössbauer parameters were different and an unusual line broadening with temperature decrease was observed. Measurements of the Ferrifol® Mössbauer spectra from 60 K to 20 K demonstrated a slow decrease of magnetic relaxation in the iron core. Zero-field-cooled and field-cooled magnetization measurements revealed a blocking temperature at ~33 K and a paramagnetic state of the Ferrifol® iron core at higher temperatures. Isothermal magnetization measurements at 5 K show that the saturation magnetic moment is ~0.31 emu/g. X-band EMR spectroscopy measurements revealed the presence of different magnetic species in the sample. Transmission electron microscopy demonstrated that the size of the iron cores in Ferrifol® is in the range 2-6 nm. The lattice periodicity in these iron cores, measured on the HRTEM images, vary in the range 2.2-2.7 Å. This can be best understood as sets of close packed O(OH) layers in ferrihydrite cores without long range correlation.
采用高分辨率透射电子显微镜(HRTEM)、X 射线衍射、热重分析、电子顺磁共振(EMR)光谱、直流磁化测量和 Fe Mössbauer 光谱研究了三价铁-多麦芽铁蛋白类似物 Ferrifol®,以获取有关铁核结构排列的新信息。在 295 K 至 90 K 的范围内测量的 Ferrifol® Mössbauer 光谱显示出非洛伦兹双峰模式。使用相同线宽的 5 个四极子双峰的叠加更好地拟合了这些光谱。获得的 Mössbauer 参数不同,并观察到异常的线宽随温度降低而变宽。从 60 K 至 20 K 测量的 Ferrifol® Mössbauer 光谱表明,铁核中的磁弛豫缓慢下降。零场冷却和场冷却磁化测量显示在~33 K 处存在阻塞温度,并且在较高温度下 Ferrifol®铁核处于顺磁状态。在 5 K 下的等温磁化测量表明饱和磁矩约为 0.31 emu/g。X 波段 EMR 光谱测量表明样品中存在不同的磁性物种。透射电子显微镜表明 Ferrifol®中铁核的尺寸在 2-6 nm 范围内。在 HRTEM 图像上测量的这些铁核中的晶格周期性在 2.2-2.7 Å 的范围内变化。这可以最好地理解为在没有长程相关性的情况下,在赤铁矿核中的紧密堆积 O(OH)层的集合。
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