Low-frequency low-field magnetic susceptibility of ferritin and hemosiderin

Abstract

Low-frequency low-field magnetic susceptibility measurements were made on four samples of mammalian tissue iron oxide deposits. The samples comprised: (1) horse spleen ferritin; (2) dugong liver hemosiderin; (3) thalassemic human spleen ferritin; and (4) crude thalassemic human spleen hemosiderin. These samples were chosen because Mössbauer spectroscopic measurements on the samples indicated that they exemplified the variation in magnetic and mineral structure found in mammalian tissue iron oxide deposits. The AC-magnetic susceptometry yielded information on the magnetization kinetics of the four samples indicating samples 1, 2, and 3 to be superparamagnetic with values of around 10(11) s(-1) for the pre-exponential frequency factor in the Néel-Arrhenius equation and values for characteristic magnetic anisotropy energy barriers in the range 250-400 K. Sample 4 was indicated to be paramagnetic at all temperatures above 1.3 K. The AC-magnetic susceptometry data also indicated a larger magnetic anisotropy energy distribution in the dugong liver sample compared with samples 1 and 3 in agreement with previous Mössbauer spectroscopic data on these samples. At temperatures below 200 K, samples 1-3 exhibited Curie-Weiss law behavior, indicating weak particle-particle interactions tending to favor antiparallel alignment of the particle magnetic moments. These interactions were strongest for the dugong liver hemosiderin, possibly reflecting the smaller separation between mineral particles in this sample. This is the first magnetic susceptometry study of hemosiderin iron deposits and demonstrates that the AC-magnetic susceptometry technique is a fast and informative method of studying such tissue iron oxide deposits.

Theory of nonexponential NMR signal decay in liver with iron overload or superparamagnetic iron oxide particles

“…In Eq. [4], V n represents the volume of the nth object and the angle brackets indicate an averaging over the object ensemble. Equation [2] is the first term of an expansion, but its precise range of validity is not, at present, rigorously known (11).…”

“…The excess iron is primarily in the forms of ferritin and hemosiderin (2), both of which have strong magnetic properties (3,4). On a cellular scale, the iron is distributed in a highly nonuniform pattern (1,2) which results in the generation of magnetic field inhomogeneities when an external magnetic field is applied.…”

Magnetic Properties of Iron Oxides in the Human Globus pallidus

“…In terms of the response to the magnetic field, three different classes of species were identified in the brain: The diamagnetic matrix (organic tissues, myelin, oxyhemoglobin), paramagnetic deoxyhemoglobin, paramagnetic/superparamagnetic ferritin and hemosiderin along with ferrimagnetic magnetite or maghemite [17][18][19].…”

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

“…The literature devoted to hemosiderin is strongly correlated with ferritin; however few studies on hemosiderin alone have been undertaken, 100,[173][174][175][176][177] although it is thought that hemosiderin may play an important role directly or indirectly in iron cytotoxicity and thus deserves more intensive study. The hemosiderin aggregates found in diseases might play a similar role as ferritin doses as precursors of BMNPs; however, no direct evidence for this is known.…”

“…173 Hemosiderin mineral particles vary even more widely in structure than those stored in ferritin. 174 Allen et al identified three main particle structures in hemosiderin: a ferrihydrite-based structure, a highly defective structure based on goethite (α-FeOOH), and a noncrystalline Fe(III) structure. 174 The same authors found that hemosiderin particles generally have larger size distributions than particles in ferritins.…”