The Faraday effect of natural and artificial ferritins

Abstract

Measurements of the Faraday rotation at room temperature over the light wavelength range of 300-680 nm for horse spleen ferritin (HSF), magnetoferritin with different loading factors (LFs) and nanoscale magnetite and Fe(2)O(3) suspensions are reported. The Faraday rotation and the magnetization of the materials studied present similar magnetic field dependences and are characteristic of a superparamagnetic system. The dependence of the Faraday rotation on the magnetic field is described, excluding HSF and Fe(2)O(3), by a Langevin function with a log-normal distribution of the particle size allowing the core diameters of the substances studied to be calculated. It was found that the specific Verdet constant depends linearly on the LF. Differences in the Faraday rotation spectra and their magnetic field dependences allow discrimination between magnetoferritin with maghemite and magnetite cores which can be very useful in biomedicine.

Micro-Raman Spectroscopy of Natural and Synthetic Ferritins and Their Mimetics

“…It may be noticed that for this particular magnetoferritin no bands related to magnetite may be observed (see Table) in agreement with magnetooptical results obtained for the same compounds [7]. In the case of the ferritin we recorded bands about 269, 332, 389, 455, 550, 642, 761, 853 and 950 cm −1 .…”

“…Of particular interest is the search for methods allowing detection and discrimination of magnetic material inside ferritin proteins both in vitro and in vivo. Very recently we showed that combined magnetooptical methods are very useful to discriminate between ferritin and magnetoferritin [6,7]. The use of the Raman spectroscopy (RS) for the detection and diagnosis in biomedicine is a growing research eld, however mostly related to oncology (e.g.…”

Physiological origin of biogenic magnetic nanoparticles in health and disease: from bacteria to humans

“…Koralewski et al proposed a magneto-optical method based on the measurement of magnetic linear birefringence (MLB; Cotton-Mouton effect) followed by that of magnetic circular birefringence dispersion (Faraday rotation dispersion, or magnetic optical rotatory dispersion [MORD]) for the discrimination of the core mineral in magnetoferritin or any other MNP. 139,[157][158][159][160] The method is depicted in Figure 11. First, MLB is measured, which allows the classification of unknown samples to a magnetically strong material, eg, magnetite or maghemite, or a magnetically weak one, eg, ferrihydrite or akaganeite (see Table 2).…”

“…159 Characteristic bands of 450-478 nm are associated with magnetite NPs and magnetoferritin with a magnetite core. Observed in the visible spectrum, this feature is directly related to Fe 2+ ions, which indicate the presence of magnetite in the studied suspension.…”

Effect of iron oxide loading on magnetoferritin structure in solution as revealed by SAXS and SANS

“…Thus, Mössbauer spectroscopy showed [11] that it is rather different from that of native ferritin. Faraday rotation measurements showed [12] that the composition of the core changes with increasing LF starting from maghemite with a relatively small fraction (about 10%) of magnetite at LF <1250 and varying towards 100 % of magnetite at LFs > 3250.…”