R. R. Gabbasov

Biodegradation of Magnetic Nanoparticles in Mouse Liver From Combined Analysis of Mössbauer and Magnetization Data

The potential of Mössbauer spectroscopy to study the biodegradation process of magnetic nanoparticles in vivo was demonstrated. Magnetic nanoparticles in form of ferrofluid were administrated to mice. The Mössbauer study of the mice liver samples has shown that in addition to the sextet of lines related to the injected nanoparticles there appears an intense doublet of lines in the spectra with increasing times after the particles administration. Further analysis showed that the doublet consists of two components related to the formation of iron-containing proteins and superparamagnetic behavior of the injected nanoparticles. Using combined analysis of three Mössbauer spectra taken at different external conditions and magnetization curves measured for each sample these components were separated and the evolution with time of each component was characterized.

Magnetic Nanoparticle Degradation in vivo Studied by Mössbauer Spectroscopy

Magnetic nanoparticles belong to the most promising nanosized objects for biomedical applications. However, little is known about clearance of magnetic nanoparticles from the organism. In this work superparamagnetic iron oxide particles fluidMAG‐ARA were injected into tail vein of mice at a dose of 17 mg per 20 g body weight. At various time intervals after the injection the mice were sacrificed and their organs collected. A Mossbauer study allowed to detect magnetic particles in the liver and spleen and showed the degradation of the particles with incorporation of exogenous iron into paramagnetic ferritin‐like iron species.

Biodegradation of Magnetic Nanoparticles in Rat Brain Studied by Mössbauer Spectroscopy

Superparamagnetic particles of Fe3O4 in ferrofluid were injected transcranially in the ventricle of the rat brain. At three months after the injection the rat was sacrificed and the brain was investigated by Mössbauer spectroscopy and histological Perls Prussian blue method. Histological examination demonstrated increased concentration of blue areas in parenchyma and on the dura mater of the brain of experimental rat in comparison with the brain of control rat, indicating appearance in the brain of some undegradable compound of iron. Mössbauer spectra showed the presence in the ferrofluid of both Fe3O4 nanoparticles and an additional chemical compound which contains ferric iron in the high-spin state. Comparison of the Mössbauer spectra of the ferrofluid, of the brain before injection and of the brain three months after injection shows that the Fe3O4 nanoparticles were removed from the brain in three months. At the same time this additional chemical compound does not decompose and remains in the brain intact.

Study of Nature of Paramagnetic Doublet in Mössbauer Spectra of Mice Liver Using External Magnetic Field

A process of the biodegradation in vivo of a magnetic ferrofluid was investigated by Mössbauer spectroscopy. After the injection of the ferrofluid in a mice body an additional doublet was observed in the Mössbauer spectra of the mice liver. Further analysis showed that the doublet consists of two components with different magnetic properties. The components related both to the formation of non-magnetic ferritin-like proteins and superparamagnetic behavior of the injected nanoparticles. These components were separated in an external magnetic field and the time evolution of each fraction was studied. The concentration of both of these fractions in the frame of multi-level relaxation model was estimated.

Synthesis and investigation of precipitated ensembles of magnetic nanoparticles with controlled easy axis orientation

Two samples with immobilized magnetic nanoparticles are synthesized and investigated. The first sample has randomly oriented easy axes of magnetic anisotropy; the second sample has preferentially aligned easy axes, produced via the precipitation of a colloid of ferromagnetic particles in the presence of a magnetic field. It is shown that the precipitation of an aqueous suspension of nanoparticles in the presence of a magnetic field greatly changes the anisotropy of a sample, compared to one prepared by precipitation without a magnetic field. The second sample exhibits a preferential direction of the easy axes of magnetic anisotropy that coincides with the direction of the external magnetic field applied in the drying process of sample preparation.

Exogenous iron redistribution between brain and liver after administering 57Fe3O4 ferrofluid to a rat brain ventricle

The natural excretion of 57Fe enriched magnetic nanoparticles from a rat’s brain through its blood–brain barrier is studied. Dextran-coated iron oxide nanoparticles are transcranially injected into the rat’s brain ventricle. The injected nanoparticles undergo biotransformation into iron-containing proteins distributed over the brain tissues, while the exogenous iron transported from the brain to other organs is eliminated from the body over time.

Investigating size effects in nanoparticles with Mössbauer and X-ray techniques

A set of samples of iron oxide nanoparticles with an amphiphilic polymer coating (Ocean Nanotech) and an average size in the range of 5–25 nm is investigated using Mössbauer and X-ray techniques. Analysis of the experimental data shows that in some cases, X-ray diffraction does not allow us to correctly determine the particle size, and Mössbauer data are needed to interpret the results correctly.

Using Mössbauer spectroscopy to interpret histological analysis data of iron-containing compounds in rat brain

Ferrofluid containing magnetic nanoparticles of Fe3O4 was introduced into the rat brain ventricle via direct transcranial injection. Three months following the injection, the rats were euthanized and their brains investigated by means of histology and Mössbauer spectroscopy. It is demonstrated that the nanoparticles completely decomposed and were cleared from the brain, while the concomitant chemical compound accompanying the ferrofluid synthesis remained intact in the brain.