Biogenic Ferrihydrite Nanoparticles: Synthesis, Properties In Vitro and In Vivo Testing and the Concentration Effect.

Sergey V Stolyar,Yulia V Gerasimova,Anna V Boldyreva,Roman N Yaroslavtsev,Elena A Birukova,Nadezda S Kudryasheva,Alexandr A Krasikov,Oleg A Bayukov,Valentina P Ladygina,Oksana A Kolenchukova

doi:10.3390/biomedicines9030323

Abstract

Biogenic ferrihydrite nanoparticles were synthesized as a result of the cultivation of Klebsiella oxytoca microorganisms. The distribution of nanoparticles in the body of laboratory animals and the physical properties of the nanoparticles were studied. The synthesized ferrihydrite nanoparticles are superparamagnetic at room temperature, and the characteristic blocking temperature is 23–25 K. The uncompensated moment of ferrihydrite particles was determined to be approximately 200 Bohr magnetons. In vitro testing of different concentrations of ferrihydrite nanoparticles for the functional activity of neutrophilic granulocytes by the chemiluminescence method showed an increase in the release of primary oxygen radicals by blood phagocytes when exposed to a minimum concentration and a decrease in secondary radicals when exposed to a maximum concentration. In vivo testing of ferrihydrite nanoparticles on Wister rats showed that a suspension of ferrihydrite nanoparticles has chronic toxicity, since it causes morphological changes in organs, mainly in the spleen, which are characterized by the accumulation of hemosiderin nanoparticles (stained blue according to Perls). Ferrihydrite can also directly or indirectly stimulate the proliferation and intracellular regeneration of hepatocytes. The partial detection of Perls-positive cells in the liver and kidneys can be explained by the rapid elimination from organs and the high dispersion of the nanomaterial. Thus, it is necessary to carry out studies of these processes at the systemic level, since the introduction of nanoparticles into the body is characterized by adaptive-proliferative processes, accompanied by the development of cell dystrophy and tension of the phagocytic system.

Highlights

The dependences of the dry weight of bacteria cultured under anaerobic conditions on media containing various forms of iron (Fe2+ oxalate and Fe3+ citrate) presented in Figure 1 clearly demonstrate that 5 days for cultivation on iron citrate are sufficient for the practical production of bacterial sediments
Nanoparticles of biogenic ferrihydrite synthesized as a result of the cultivation of Klebsiella oxytoca bacteria were studied
The study of the organic shell covering the surface of the nanoparticles by IR spectroscopy showed that it consists of polysaccharides

Summary

Introduction

Ferrihydrite Fe2 O3 ·nH2 O or oxyhydroxide Fe3+ , in comparison with Fe3+ hydroxides and oxides, is the compound with the highest metastability. Ferrihydrite plays a huge role in the metabolism of living organisms. It is formed in the core of the protein complex named ferritin, which is a capsule of the protein apoferritin. The size of the ferrihydrite nanoparticles is typically in a narrow range from 2 to 8 nm. The Fe2 O3 ·nH2 O → hematite transformation occurs [1]. The ability of enterobacteria Klebsiella oxytoca, isolated from pyrite deposits, to ferment iron citrate under anaerobic conditions and to form a trivalent metal hydrogel was first reported in [2]

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