Iron is essential element for fundamental cell functions, catalyst for chemical reaction. Iron can be found in human body mainly in the form of ferritin - 5Fe2O3.9H2O.
57Fe Mössbauer spectrometry, X4ray powder diffraction, (XRD), X4ray fluorescence (XRF), scanning and transmission electron microscopy (TEM) were carried out for investigation of iron oxide particles in human spleens with diagnosis of hemosiderosis, hereditary spherocytosis, and reference sample.
Room temperature Mössbauer spectra of all investigated samples exhibit doublet4like features identified as Fe(III) predominantly in ferrihydrite and haem environments within the tissue. Low temperature Mössbauer effect measurements at 77 K revealed, however, no changes in the magnetic ordering of the investigated samples. A contribution of ferromagnetically split sextets is clearly seen for all investigated samples measured at 5K. Their occurrence indicates that part of the sample is magnetically ordered, i.e. below the blocking temperature of a superparamagnetic behaviour. The ratio of relative contents of doublet to sextet components suggests differences in the size of ferritin cores in the investigated samples. The hemosiderosis sample exhibits the largest ferritin core which, in turn, stores the highest amount of Fe and thus triggers this disease.
Additional structural characterization is obtained from powder XRD and XRF measurements. XRF results show presence of different chemical elements such as iron, sulphur, phosporus, chlorine, zinc, chromium, and bromine. TEM investigation reveals iron accumulation in macrophages of the human spleen. The size of the particles is around 5 μm.
The amount of chemical elements and pH in surrounding environments can influence iron oxidation status and may cause transformation of biogenic to abiogenic (toxic) character of ferritin.