Study of ferritin nanoparticles

Moessbauer spectrometry confirms the presence of hematite, ferrihydrite and maghemite/magnetite in ferritin derived from human spleen tissues. The minerals are present in a form of small (about 4-5 nm in size) grains with highly disordered structure. Consequently, at room temperature all agglomerates of ferritin nanoparticles show non-magnetic behaviour. Magnetic states are revealed at low enough temperatures below the so-called blocking temperature. Employing Moessbauer effect measurements, the latter was determined to be of 16 K for the human spleen. Structural features of these tissues were studied by TEM technique. Employing ⁵⁷Fe nuclei as local probes both structural and magnetic features of the biological materials were investigated by Moessbauer spectrometry. It was possible to identify iron atoms and their neighbours. (authors)