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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Krasikov A. A., Knyazev Yu. V., Yaroslavtsev R. N., Velikanov D. A., Mikhlin Yu. L., Volochaev M. N., Bayukov O. A., Ladygina V. P., Stolyar S. V., Iskhakov R. S.
Заглавие : Magnetic collective state formation upon tuning the interparticle interactions in ensembles of ultrafine ferrihydrite nanoparticles
Колич.характеристики :13 с
Место публикации : Nano-Struct. Nano-Objects. - 2024. - Vol. 37. - Ст.101089. - ISSN 2352507X (ISSN), DOI 10.1016/j.nanoso.2023.101089. - ISSN 23525088 (eISSN)
Примечания : Cited References: 93. - The authors thank M.N. Volochaev for the TEM investigations
Аннотация: The results of a study of the dynamic (alternating current magnetic susceptibility) and static magnetic properties, as well as 57Fe Mössbauer spectrometry and ferromagnetic resonance of two-line ferrihydrite nanoparticle systems with varying intensities of magnetic interparticle interactions are reported. The strength of the magnetic interparticle interactions has been tuned by coating (with various degrees of coating) the ferrihydrite particles (2–4 nm in size and an average size ∼2.7 nm) of the initial synthetic sample by arabinogalactan. Also, a biogenic ferrihydrite sample (an average particle size of 2-nm) with a natural organic coating was studied and it has the weakest magnetic interparticle interactions among of all the samples. Relaxation times of the particle’s magnetic moment were determined by the data of static and dynamic magnetic susceptibilities and from analysis of 57Fe Mössbauer spectrometry. Based on the temperature dependences of the relaxation times, it has been concluded that the predominantly collective processes of freezing of the particle magnetic moments occur under the action of the magnetic interparticle interactions. It is shown that an important role in these processes is played by a magnetic subsystem of the surface spins of the particles. The effect of the interplay between the surface spin and magnetic moment subsystems on the static magnetic properties (low-temperature magnetic hysteresis loops) and the parameters of the microwave absorption line under the magnetic resonance conditions is discussed.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krasikov A. A., Balaev D. A., Balaev A. D., Stolyar S. V., Yaroslavtsev R. N., Iskhakov R. S.
Заглавие : Separating the contributions of the magnetic subsystems in antiferromagnetic ferrihydrite nanoparticles by analyzing the magnetization in fields of up to 250 kOe
Колич.характеристики :8 с
Место публикации : J. Magn. Magn. Mater. - 2024. - Vol. 592. - Ст.171781. - ISSN 03048853 (ISSN), DOI 10.1016/j.jmmm.2024.171781. - ISSN 18734766 (eISSN)
Примечания : Cited References: 84. - This study was supported by his work was supported by the Russian Science Foundation, project no. 22–72-00134Authors thank to D.A. Velikanov, S.V. Komogortsev for fruitful discussions
Аннотация: Contributions of different magnetic subsystems formed in the systems of synthetic ferrihydrite nanoparticles (characterized previously) with an average size of ˂d˃ ≈ 2.7 nm coated with polysaccharide arabinogalactan in different degrees have been separated by measuring the dependences of their magnetization M on magnetic field H of up to 250 kOe on vibrating sample and pulsed magnetometers. The use of a wide measuring magnetic field range has been dictated by the ambiguity in identifying a linear M(H) portion for such antiferromagnetic nanoparticle systems within the conventional field range of 60–90 kOe. The thorough analysis of the magnetization curves in the temperature range of 100–250 K has allowed the verification of the contributions of (i) uncompensated magnetic moments µun in the superparamagnetic subsystem, (ii) the subsystem of surface spins with the paramagnetic behavior, and (iii) the antiferromagnetic susceptibility of the antiferromagnetically ordered ferrihydrite particle core. As a result, a model of the magnetic state of ferrihydrite nanoparticles has been proposed and the numbers of spins corresponding to magnetic subsystems (i)–(iii) have been estimated. An average magnetic moment μun of ∼ 145 μB (μB is the Bohr magneton) per particle corresponds approximately to 30 decompensated spins of iron atoms in a particle (about 3 % of all iron atoms), which, according to the Néel’s hypothesis μun ∼ ˂d˃3/2, are localized both on the surface and in the bulk of an antiferromagnetically ordered particle. The fraction of free (paramagnetic) spins is minimal in the sample without arabinogalactan coating of the nanoparticle surface (7 %) and is attained 20 % of all iron atoms in the sample with the highest degree of spatial separation of particles. According to this estimation, paramagnetic spins are located mainly on the edges and protruding areas of particles. Most magnetic moments of iron atoms are ordered antiferromagnetically and the corresponding magnetic susceptibility of this subsystem behaves as in an antiferromagnet with the randomly distributed crystallographic axes, i.e., increases with temperature.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stolyar S. V., Li O. A., Vorotynov A. M., Velikanov D. A., Maksimov N. G., Iskhakov R. S., Ladygina V. P., Shokhrina A. O.
Заглавие : Studying the ferromagnetic resonance heating of an isotropic superparamagnet by the example of biogenic ferrihydrite nanoparticles
Колич.характеристики :4 с
Место публикации : Bull. Russ. Acad. Sci.: Phys. - 2024. - Vol. 88, Is. 4. - P.536-539. - ISSN 10628738 (ISSN), DOI 10.1134/S106287382370627X. - ISSN 19349432 (eISSN)
Примечания : Cited References: 10
Аннотация: Ferrihydrite nanoparticles are synthesized and characterized. The dependences of heating of powders are studied upon pumping by a high-frequency electromagnetic field on a dc magnetic field. It is shown that the experimental dependence of the temperature of particles on a dc magnetic field is consistent with the theory of ferromagnetic resonance for an isotropic superparamagnet.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krasikov A. A., Knyazev Yu. V., Balaev D. A., Velikanov D. A., Stolyar S. V., Mikhlin Yu. L., Yaroslavtsev R. N., Iskhakov R. S.
Заглавие : Interparticle magnetic interactions and magnetic field dependence of superparamagnetic blocking temperature in ferrihydrite nanoparticle powder systems
Место публикации : Phys. B: Condens. Matter. - 2023. - Vol. 660. - Ст.414901. - ISSN 09214526 (ISSN), DOI 10.1016/j.physb.2023.414901. - ISSN 18732135 (eISSN)
Примечания : Cited References: 66. - This study was supported by his work was supported by the Russian Science Foundation, project no. 22-72-00134
Аннотация: In this study, nanoparticles of initial synthetic ferrihydrite have been coated with arabinogalactan. The synthesized series of samples with different degrees of coverage of particles has been characterized by X-ray photoelectron spectroscopy, Mossbauer spectroscopy, transmission electron microscopy and magnetometry. The superparamagnetic blocking temperature decreases monotonically with an increase in the degree of coverage of ferrihydrite particles, which is unambiguously related to the different role of the interparticle magnetic interactions in the investigated powder systems. Analysis of the field dependence of the blocking temperature within the random anisotropy model has shown that an increase in the degree of coverage of ferrihydrite particles leads to a decrease in the size of a cluster in which the behaviors of the nanoparticle magnetic moments are correlated. The results obtained have shown the possibility of effective control of the strength of magnetic interparticle interactions in powder ferrihydrite systems by coating nanoparticles with arabinogalactan.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Balaev D. A., Skorobogatov S. A., Velikanov D. A., Bayukov O. A., Stolyar S. V., Yaroslavtsev R. N., Iskhakov R. S.
Заглавие : Spin dynamics in ensembles of ultrafine ferrihydrite nanoparticles
Место публикации : Phys. Rev. B. - 2023. - Vol. 107, Is. 11. - Ст.115413. - ISSN 24699950 (ISSN), DOI 10.1103/PhysRevB.107.115413. - ISSN 24699969 (eISSN)
Примечания : Cited References: 66. - The electron microscopy study and ac susceptibility measurements were carried out on the equipment of the Krasnoyarsk Territorial Center for Collective Use, Krasnoyarsk Scientific Center, Siberian Branch of the Russian Academy of Sciences. This study was supported by the Russian Science Foundation, Project No. 21-72-00025 Tuning the Magnetic Properties of Ultrafine Biocompatible Ferrihydrite Nanoparticles through Interparticle Interactions [66]
Аннотация: Features of the spin dynamics in ensembles of interacting (FH-chem) and weakly interacting (FH-coated) magnetic ultrasmall (‹d› ∼ 2 nm) ferrihydrite nanoparticles have been explored. The dc and ac magnetic susceptibilities [χ'(T ) and χ''(T )] of the investigated samples have been thoroughly measured in a weak magnetic field (2 Oe) around the temperatures of superparamagnetic blocking of the nanoparticle magnetic moments (19 and 50.4 K for FH-coated and FH-chem, respectively, according to the dc magnetization data). It has been shown that the magnetic interactions between nanoparticles induce the formation of the cluster spin-glass state below the superparamagnetic blocking temperature (Tg = 18 and 49.5 K for FH-coated and FH-chem, respectively). It has been found that coating of nanoparticles increases the critical scaling index from zν = 5.9 (FH-chem) to zν = 8.0 (FH-coated). This indicates a general slowdown of the dynamics of correlated spins, which is also expressed as an increase in relaxation time τ0 after switching on the interparticle interactions. We attribute this phenomenon to a consequence of a change in the volume of correlated spins with the increasing size of a cluster of interacting nanoparticles. It has been demonstrated using the simulated χ''(T ) dependence that the dissipation of the magnetic energy occurs in two independent stages. The first stage is directly related to the blocking of the nanoparticle magnetic moments, while the second stage reflects the spin-glass behavior of surface spins and depends strongly on the intensity of the interparticle interactions.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krasikov A. A., Knyazev Yu. V., Balaev D. A., Stolyar S. V., Ladygina V. P., Balaev A. D., Iskhakov R. S.
Заглавие : Magnetic interparticle interactions and superparamagnetic blocking of powder systems of biogenic ferrihydrite nanoparticles
Колич.характеристики :11 с
Место публикации : J. Exp. Theor. Phys. - 2023. - Vol. 137, Is. 6. - P.903-913. - ISSN 10637761 (ISSN), DOI 10.1134/S1063776123120075. - ISSN 10906509 (eISSN)
Примечания : Cited References: 58. - This study was supported by the Russian Science Foundation, project no. 22-72-00134
Аннотация: The magnetic-field dependence of the superparamagnetic-blocking temperature TB of systems of antiferromagnetically ordered ferrihydrite nanoparticles has been investigated and analyzed. We studied two powder systems of nanoparticles: particles of “biogenic” ferrihydrite (with an average size of 2.7 nm), released as a result of vital functions of bacteria and coated with a thin organic shell, and particles of biogenic ferrihydrite subjected to low-temperature annealing, which cause an increase in the average particle size (to 3.8 nm) and burning out of the organic shell. The character of the temperature dependences of magnetization, measured after cooling in a weak field, as well as the shape of the obtained dependences TB(H), demonstrate peculiar features, indicating the influence of magnetic interparticle interactions. A detailed analysis of the dependences TB(H) within the random magnetic anisotropy model made it possible to estimate quantitatively the intensity of magnetic particle–particle interactions and determine the magnetic anisotropy constants of individual ferrihydrite particles.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Balaev D. A., Skorobogatov S. A., Velikanov D. A., Bayukov O. A., Stolyar S. V., Yaroslavtsev R. N., Iskhakov R. S., Knyazev Yu. V.
Заглавие : Superparamagnetic relaxation in ensembles og ultrasmall ferrihydrite nanoparticles
Коллективы : Байкальская международная конференция "Магнитные материалы. Новые технологии", "Магнитные материалы. Новые технологии", Байкальская международная конференция, "Magnetic materials. New tecnologies", Baikal International Conference, Иркутский государственный университет
Место публикации : Магнитные материалы. Новые технологии: тез. докл. IX Байкал. междунар. конф. BICMM-2023/ чл. прогр. ком.: S. S. Aplesnin [et al.] ; чл. орг. ком. R. S. Iskhakov [et al.]. - Иркутск, 2023. - P.92. - ISBN 978-5-962402178-0
Примечания : Библиогр.: 1
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Stolyar S. V., Knyazev Yu. V., Yaroslavtsev R. N., Pankrats A. I., Vorotynov A. M., Krasikov A. A., Velikanov D. A., Bayukov O. A., Ladygina V. P., Iskhakov R. S.
Заглавие : Role of the surface effects and interparticle magnetic interactions in the temperature evolution of magnetic resonance spectra of ferrihydrite nanoparticle ensembles
Место публикации : Results Phys. - 2022. - Vol. 35. - Ст.105340. - ISSN 22113797 (ISSN), DOI 10.1016/j.rinp.2022.105340
Примечания : Cited References: 119. - Authors thank to A.D. Balaev, S.V. Komogortsev for fruitful discussions and M.N. Volochaev for TEM studies. The TEM study and measurements of X-band FMR spectra were carried out on the equipment of the Krasnoyarsk Territorial Center for Collective Use, Krasnoyarsk Scientific Center, Siberian Branch, Russian Academy of Sciences. This study was supported by the Russian Science Foundation, project no. 21-72-00025 (https://rscf.ru/project/21-72-00025/) "Tuning the Magnetic Properties of Ultrafine Biocompatible Ferrihydrite Nanoparticles through Interparticle Interactions"
Аннотация: Ferrihydrite is characterized by the antiferromagnetic ordering and, in ferrihydrite nanoparticles, as in nanoparticles of any antiferromagnetic material, an uncompensated magnetic moment is formed. We report on the investigations of ferrihydrite powder systems with an average particle size of ∼ 2.5 nm obtained (i) as a product of the vital activity of bacteria (sample FH-bact) and (ii) by a chemical method (sample FH-chem). In the first approximation, these samples can be considered to be identical. However, in sample FH-chem, particles contact directly, while in sample FH-bact, they have organic shells; therefore, the interparticle magnetic interactions in these samples have different degrees. The main goal of this work has been to establish the effects of the interparticle magnetic interactions and individual characteristics of ferrihydrite nanoparticles on ferromagnetic resonance (FMR) spectra. The FMR spectra have been measured at different (9.4–75 GHz) frequencies in a wide temperature range. It has been found that, at low temperatures, the field-frequency dependence ν(HR) of the investigated systems has a gap ν/γ = HR + HA, where HR is the resonance field and HA is the induced anisotropy, which decreases with increasing temperature. To estimate a degree of the effect of interparticle interactions on the results obtained and to correctly determine the temperature range of the superparamagnetic (or blocked) state, the static magnetic measurement and Mössbauer spectroscopy data have been obtained and analyzed. It has been shown that the most striking feature of the FMR spectra - a gap in the field-frequency dependences - is a manifestation of individual characteristics of ferrihydrite nanoparticles. The induced anisotropy is caused by freezing of a subsystem of surface spins and its coupling with the particle core, which is observed in both samples at a temperature of ∼80 K. The temperature range (below 80 K) in which the gap exists corresponds to the blocked state in the FMR technique. In sample FH-bact, the ratio between the FMR parameters HA and linewidth ΔH obeys the standard expression HA ∼ (ΔH)3. In sample FH-chem, however, the interparticle magnetic interactions dramatically affect the behavior of parameters of the FMR spectra, which change nonmonotonically upon temperature variation. This fact is attributed to the collective freezing of the magnetic moments of particles under the conditions of sufficiently strong interactions, which follows from the temperature dependence of the particle magnetic moment relaxation time determined from the Mössbauer spectroscopy and static magnetometry data obtained in weak magnetic fields.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stolyar S. V., Bayukov O. A., Balaev D. A., Ladygina V. P., Yaroslavtsev R. N., Knyazev Yu. V., Balasoiu M., Kolenchukova O. A., Iskhakov R. S.
Заглавие : Ferrihydrite nanoparticles produced by Klebsiella oxytoca: Structure and properties dependence on the cultivation time
Место публикации : Adv. Powder Technol. - 2022. - Vol. 33, Is. 8. - Ст.103692. - ISSN 09218831 (ISSN), DOI 10.1016/j.apt.2022.103692
Примечания : Cited References: 59. - This work was supported by Russian Foundation for Basic Research, Government of Krasnoyarsk Territory, Krasnoyarsk Region Science and Technology Support Fund to the research projects No. 20-416-242907
Аннотация: Ferrihydrite nanoparticles were synthesized using Klebsiella oxytoca microorganisms under various cultivation conditions. The cultivation of bacteria was carried out under various lighting conditions, and the duration of cultivation varied from 3 to 56 days. Biogenic ferrihydrite nanoparticles were studied by Mössbauer spectroscopy, magnetometry, and small-angle X-ray scattering. The process of formation of ferrihydrite nanoparticles and the states arising during the cultivation of microorganisms have been investigated. The results of Mössbauer spectroscopy showed that, depending on the time of cultivation, three different states of ferrihydrite can be realized. States differ both in the ratio of defective and non-defective positions, and the size of the particle. Experimental results indicate that ferrihydrite nanoparticles are a system of variable composition and pass through several structural (or morphological) states during the cultivation of microorganisms. A model of the structure of ferrihydrite nanoparticles is proposed, which consists in the presence of an antiferromagnetic dense core with a high Néel temperature and a friable shell with a significantly lower temperature of magnetic ordering.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Balaev D. A., Stolyar S. V., Krasikov A. A., Bayukov O. A., Volochaev M. N., Yaroslavtsev R. N., Ladygina V. P., Velikanov D. A., Iskhakov R. S.
Заглавие : Interparticle magnetic interactions in synthetic ferrihydrite: Mossbauer spectroscopy and magnetometry study of the dynamic and static manifestations
Место публикации : J. Alloys Compd. - 2022. - Vol. 889. - Ст.161623. - ISSN 09258388 (ISSN), DOI 10.1016/j.jallcom.2021.161623
Примечания : Cited References: 84. - This study was supported by the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Territory, and the Krasnoyarsk Territorial Foundation for Support of Scientific and R&D Activities, project no. 19–42–240012 R-A “Magnetic Resonance in Ferrihydrite Nanoparticles: Effects Related to the Core-Shell Structure”
Аннотация: Samples of synthetic ferrihydrite with an average nanoparticle size of 2.7 nm have been examined by magnetometry and Mossbauer spectroscopy. Ferrihydrite is characterized by the antiferromagnetic interactions between the magnetic moments of iron atoms. In ferrihydrite nanoparticles, as in any other antiferromagnetic ones, structural defects induce the formation of an uncompensated magnetic moment, which determines the magnetic properties typical of single-domain ferro- and ferrimagnetic particles. The manifestation of the magnetic interactions between ferrihydrite nanoparticles in the magnetic properties of the material and in the temperature evolution of Mossbauer spectra has been in focus. The results obtained on synthetic ferrihydrite have been compared with the data for the biogenic ferrihydrite sample with a similar average size of particles surrounded by a polysaccharide shell, which weakens and screens the interparticle magnetic interactions. A clear manifestation of the effect of the interparticle magnetic interactions on the transition to the blocked state is the presence of a significant contribution of the relaxation component in the Mossbauer spectra at temperatures of the transition from the superparamagnetic to blocked state. The temperature dependence of the particle relaxation time obtained from the Mossbauer spectra points out the collective effect of freezing of the magnetic moments of particles due to the magnetic interactions between them.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Cazacu, Nicoleta, Chilom, Claudia G., Iftimie, Sorina, Balasoiu, Maria, Ladygina, Valentina P., Stolyar S. V., Orelovich, Oleg L., Kovalev, Yuriy S., Rogachev, Andrey V.
Заглавие : Biogenic ferrihydrite nanoparticles produced by Klebsiella oxytoca: Characterization, physicochemical properties and bovine serum albumin interactions
Место публикации : Nanomaterials. - 2022. - Vol. 12, Is. 2. - Ст.249. - ISSN 2079-4991(eISSN), DOI 10.3390/nano12020249
Примечания : Cited References: 59. - This research was funded by JINR Themes 02-1-1107-2011/2021, 04-5-1131-2017/2021 and 04-4-1133-2018/2023 and with the financial support of the RO-JINR Projects Nos. 366/11.05.2021 (items 7, 86, 97) and 365/11.05.2021 (items 8, 87 and 98). This work also benefited from the use of the SasView application, originally developed under NSF Award DMR-0520547. SasView also contains the code developed with funding from the EU Horizon 2020 program under the SINE2020 project Grant No 654000. The APC was funded by JINR Theme 02-1-1107-2011/2021, Project No. 366/11.05.2021, item 7. This study used the infrastructure of the Applied Genetics Resource Facility of MIPT (Suport Grant 075-15-2021-684)
Предметные рубрики: MAGNETIC-PROPERTIES
REDUCTION
MOSSBAUER
FERRITIN
DOCKING
BINDING
Аннотация: The synthesis of nanoparticles inside microorganisms is an economical alternative to chemical and physical methods of nanoparticle synthesis. In this study, ferrihydrite nanoparticles synthesized by Klebsiella oxytoca bacterium in special conditions were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS), small-angle X-ray (SAXS), UV-Vis spectroscopy, fluorescence, fluorescence resonance energy transfer (FRET), and molecular docking. The morphology and the structure of the particles were characterized by means of SEM and SAXS. The elemental content was determined by means of the EDS method. The absorption properties of the ferrihydrite nanoparticles were investigated by UV-Vis spectroscopy. The binding mechanism of the biogenic ferrihydrite nanoparticles to Bovine Serum Albumin (BSA) protein, studied by fluorescence, showed a static and weak process, combined with FRET. Protein denaturation by temperature and urea in the presence of the ferrihydrite nanoparticles demonstrated their influence on the unfolding process. The AutoDock Vina and UCSF Chimera programs were used to predict the optimal binding site of the ferrihydrite to BSA and to find the location of the hydrophobic cavities in the sub-domain IIA of the BSA structure.
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12.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Stolyar S. V., Li O. A., Ladygina V. P., Nikolaeva E. D., Vorotynov A. M., Velikanov D. A., Pyankov V. F., Iskhakov R. S.
Заглавие : Heat release by ferrihydrite nanoparticles at ferromagnetic resonance
Коллективы : Российская академия наук, Физико-технический институт им. Е.К. Завойского ФИЦ Казанского научного центра РАН, Казанский (Приволжский) федеральный университет, Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium
Место публикации : VIII Euro-Asian symposium "Trends in magnetism" (EASTMAG-2022): Book of abstracts/ program com. S. G. Ovchinnikov [et al.]. - 2022. - Vol. 2, Sect. M: Magnetism in biology and medicine. - Ст.M.P5. - P.434. - ISBN 978-5-94469-051-7
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Богатиков А. А., Добрецов К. Г., Мелихова М. В., Рожко М. А., Лапина Н. В., Столяр, Сергей Викторович, Ярославцев, Роман Николаевич, Баюков, Олег Артемьевич, Тюменцева А. В., Николаева Е. Д., Тютрина Е. С., Зиновьев Е. В.
Заглавие : Новый способ лечения ожоговых ран с помощью адресной доставки лекарственных веществ магнитным наноносителем (экспериментальная часть)
Место публикации : Журн. СФУ. Биология. - 2022. - Т. 15, № 3. - С. 422-436. - ISSN 19971389 (ISSN), DOI 10.17516/1997-1389-0396; J. Sib. Fed. Univ. Biol. - ISSN 23135530 (eISSN)
Примечания : Библиогр.: 27. - Работа выполнена при финансовой поддержке Красноярского краевого фонда науки, Конкурс проектов организации участия студентов, аспирантов и молодых ученых в конференциях, научных мероприятиях и стажировках (II очередь 2021 года) (проект № 2021051707717)
Аннотация: Проведено экспериментальное исследование на лабораторных животных по изучению эффективности адресной доставки мази левомеколь с помощью магнитных наночастиц и внешнего магнитного поля при термических ожогах. В исследовании принимало участие 20 крыс с двумя очагами ожога. Крысы были разделены на 4 группы: без лечения, терапия с использованием мази левомеколь, лечение с использованием наночастиц, мази левомеколь и внешнего магнитного поля и только магнитотерапии. При гистологическом исследовании на 14-е сутки во всех группах в зоне термического повреждения кожи были отмечены признаки глубокого ожога III и IV степени с распространением некроза на всю глубину дермы и на мышцы. В группе с наночастицами, мазью левомеколь и магнитным полем на фоне уменьшения воспаления отмечалось очаговое появление грануляционной ткани. Таким образом, гистологические исследования ожогового раневого процесса лабораторных животных показали, что использование инновационного биологически активного ранозаживляющего средства на основе наночастиц в сочетании с мазью левомеколь улучшает регенерацию тканей и приводит к ускорению эпителизации, что в целом повышает результаты лечения ожоговой раны. Использование внешнего магнитного поля способствует адресной доставке лечебного нанокомплекса и поддержанию оптимальной концентрации препарата в ране.Experimental studies have been carried out on laboratory animals to investigate the effectiveness of targeted delivery of levomekol ointment using magnetic nanoparticles and an external magnetic field for treatment of thermal burns. The study involved 20 rats, with two burns on each. The rats were divided into 4 groups: untreated; treated with levomekol ointment; treated with levomekol ointment associated with nanoparticles and an external magnetic field; and treated with magnetic field alone. Histological examination was conducted on Day 14, and in all groups, in the thermal burn zone of the skin there were signs of deep three- and four-degree burns with necrosis spread through the dermis, reaching the muscle. In the group with levomekol ointment associated with nanoparticles and magnetic field, inflammation was decreased, and focal granulation tissue formation was observed. Thus, histological studies of the burn wound process in laboratory animals showed that the use of an innovative biologically active wound healing agent based on nanoparticles in combination with the levomecol ointment improved tissue regeneration and accelerated epithelialization, which enhanced the effectiveness of burn wound treatment. The use of an external magnetic field facilitated targeted delivery of the therapeutic nanosystem and maintenance of the optimal concentration of the drug in the wound.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Ikkert O. P., Semenov S. V., Volochaev M. N., Molokeev M. S., Platunov M. S., Khramov E. V., Dubrovskiy A. A., Shestakov N. P., Smorodina E. D., Karnachuk O. V., Balaev D. A.
Заглавие : Superparamagnetic blocking and magnetic interactions in nanoferrihydrite adsorbed on biomineralized nanorod-shaped F3S4 crystallites
Место публикации : J. Alloys Compd. - 2022. - Vol. 923. - Ст.166346. - ISSN 09258388 (ISSN), DOI 10.1016/j.jallcom.2022.166346
Примечания : Cited References: 109. - This study was supported by the Russian Science Foundation, project no. 22-24-00601 (https://rscf.ru/project/22–24–00601/)The electron microscopy and Mössbauer spectroscopy studies were carried out on the equipment of the Krasnoyarsk Territorial Center for Collective Use, Krasnoyarsk Scientific Center, Siberian Branch of the Russian Academy of Sciences. We thank Dr. Ivan Nemtsev for the SEM images. The contribution of M. P. (development of methodology of sample preparation for EXAFS measurements) was partially supported by the Russian Ministry of Science and Higher Education via the budget project of SRF SKIF, Boreskov Institute of Catalysis
Аннотация: A composite based on nanorod-shaped greigite (Fe3S4) crystallites with adsorbed ferrihydrite (Fe2O3 ‧ nH2O) nanoparticles has been synthesized. The synthesis has been performed by biomineralization of the bacterial wall of a sulfate-reducing Desulfovibrio sp. A2 bacteria. The phase composition of the synthesized composite has been investigated by X-ray powder and electron diffraction, as well as Fourier-transform infrared, extended X-ray absorption fine structure, and Mössbauer spectroscopy. The magnetic measurement data have shown that the sample under study contains two magnetic phases: multidomain nanorod-shaped greigite and ultrasmall ferrihydrite nanoparticles. The constant atomic fraction of the greigite crystalline phase in the range of 4–300 K (~20%) revealed by Mössbauer spectroscopy is indicative of a blocked magnetic moment of nanorod-shaped Fe3S4. It is shown that nanorod-shaped Fe3S4 crystallites are strongly magnetically bound with adsorbed Fe2O3 ‧ nH2O (Eint ~ 1200kB) nanoparticles. This significantly slows down the superparamagnetic relaxation of the magnetic moments of ferrihydrite nanoparticles. Therefore, the blocking temperature noticeably increases and attains, according to the Mössbauer spectroscopy data, a value of TB = 140 K (the magnetic measurements yield TB = 72 K). The processes of superparamagnetic blocking of the magnetic moments of ferrihydrite nanoparticles manifest themselves in the evolution of the magnetic properties of the investigated sample (a significant increase in the coercivity and remanent magnetization). In support of the Mössbauer spectroscopy data, a sufficiently high superparamagnetic blocking temperature has been established, which discloses the effect of magnetizing of ferrihydrite nanoparticles by coarser greigite formations, analogously to the effect of interparticle magnetic interactions.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Balaev D. A., Yaroslavtsev R. N., Krasikov A. A., Velikanov D. A., Mikhlin Y. L., Volochaev M. N., Bayukov O. A., Stolyar S. V., Iskhakov R. S.
Заглавие : Tuning of the interparticle interactions in ultrafine ferrihydrite nanoparticles
Место публикации : Adv. Nano Res. - 2022. - Vol. 12, Is. 6. - P.605-616. - ISSN 2287237X (ISSN), DOI 10.12989/anr.2022.12.6.605
Примечания : Cited References: 73. - This study was supported by the Russian Science Foundation, project no. 21-72-00025 “Tuning the Magnetic Properties of Ultrafine Biocompatible Ferrihydrite Nanoparticles through Interparticle Interactions” (https://rscf.ru/project/21-72-00025/)
Аннотация: We prepared two samples of ultrafine ferrihydrite (FH) nanoparticle ensembles of quite a different origin. First is the biosynthesized sample (as a product of the vital activity of bacteria Klebsiella oxytoca (hereinafter marked as FH-bact) with a natural organic coating and negligible magnetic interparticle interactions. And the second one is the chemically synthesized ferrihydrite (hereinafter FH-chem) without any coating and high level of the interparticle interactions. The interparticle magnetic interactions have been tuned by modifying the nanoparticle surface in both samples. The coating of the FH-bact sample has been partially removed by annealing at 150℃ for 24 h (hereinafter FH-annealed). The FH-chem sample, vice versa, has been coated (1.0 g) with biocompatible polysaccharide (arabinogalactan) in an ultrasonic bath for 10 min (hereinafter FH-coated). The changes in the surface properties of nanoparticles have been controlled by XPS. According to the electron microscopy data, the modification of the nanoparticle surface does not drastically change the particle shape and size. A change in the average nanoparticle size in sample FH-annealed to 3.3 nm relative to the value in the other samples (2.6 nm) has only been observed. The estimated particle coating thickness is about 0.2-0.3 nm for samples FH-bact and FH-coated and 0.1 nm for sample FH-annealed. Mössbauer and magnetization measurements are definitely shown that the drastic change in the blocking temperature is caused by the interparticle interactions. The experimental temperature dependences of the hyperfine field hf(T) for samples FH-bact and FH-coated have not revealed the effect of interparticle interactions. Otherwise, the interparticle interaction energy Eint estimated from the hf(T) for samples FH-chem and FH-annealed has been found to be 121kB and 259kB, respectively.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Komogortsev S. V., Balaev D. A., Krasikov A. A., Stolyar S. V., Yaroslavtsev R. N., Ladygina V. P., Iskhakov R. S.
Заглавие : Magnetic hysteresis of blocked ferrihydrite nanoparticles
Место публикации : AIP Adv. - 2021. - Vol. 11, Is. 1. - Ст.015329. - ISSN 21583226 (ISSN), DOI 10.1063/9.0000111
Примечания : Cited References: 23. - The magnetic measurements were partially carried out on the equipment of the Krasnoyarsk Regional Center for Collective Use, Krasnoyarsk Science Center, Siberian Branch, Russian Academy of Sciences. This study was supported by the Council of the President of the Russian Federation for State Support of Young Scientists and Leading Scientific Schools (project no. MK-1263.2020.3)
Аннотация: Using minor hysteresis loops in the Stoner-Wohlfarth model allows describing the experimental behavior of the coercive force of minor hysteresis loops in ferrihydrite nanoparticles with a change in the field amplitude. The description allows estimating the parameters of the distribution of the magnetic anisotropy field in nanoparticles. The best agreement of the anisotropy fields estimated by different approaches is achieved for the assumption of uniaxial anisotropy in ferrihydrite nanoparticles.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Balaev D. A., Stolyar S. V., Bayukov O. A., Yaroslavtsev R. N., Ladygina V. P., Velikanov D. A., Iskhakov R. S.
Заглавие : Magnetic anisotropy and core-shell structure origin of the biogenic ferrihydrite nanoparticles
Место публикации : J. Alloys Compd. - 2021. - Vol. 851. - Ст.156753. - ISSN 09258388 (ISSN), DOI 10.1016/j.jallcom.2020.156753
Примечания : Cited References: 82. - The electron microscopy study was carried out on the equipment of the Krasnoyarsk Territorial Center for Collective Use, Krasnoyarsk Scientific Center, Siberian Branch, Russian Academy of Sciences. This study was supported by the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Territory, and the Krasnoyarsk Territorial Foundation for Support of Scientific and R & D Activities, project no. 19-42-240012 p-a “Magnetic Resonance in Ferrihydrite Nanoparticles: Effects Related to the Core–Shell Structure”
Аннотация: Ferrihydrite is a low-crystalline nanoscale matter. The uncompensated magnetic moment of the ferrihydrite caused by the antiferromagnetic ordering of the magnetic moments of iron atoms and leads to the magnetic properties very similar to those of ferro- and ferrimagnetic nanoparticles. In this study, we investigated the biogenic ferrihydrite nanoparticles with the narrow size distribution and an average diameter of ≈2 nm obtained by the bacteria life cycle. The features caused by the surface effects and the inhomogeneous structure of ferrihydrite have been examined in the temperature range of 4–300 K using Mossbauer spectroscopy and magnetometry. Based on the Mossbauer data, we identified the superparamagnetic blocking temperature at the temperature of 30 K for the largest ferryhidrite particles. We established that the exceptional magnetic anisotropy of ferrihydrite (KV=1.2∙105 erg/cm3 and KS=0.1 erg/cm2) is reached because of the highly developed ferrihydrite nanoparticles’ surface. According to the Mossbauer data, we propose a core-shell structural model of the biogenic ferrihydrite particles. We found that the size of the dense core depends on the particle size. The well-crystallized core is formed only for nanoparticles larger than ≈2 nm, whereas smaller particles consist entirely of a matter with a lower density of iron atoms.
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18.

Вид документа : Статья из журнала
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Автор(ы) : Chilom C. G., Sandu N., Iftimie S., Balasoiu M., Rogachev A., Orelovich O., Stolyar S. V.
Заглавие : Interactions of chemically synthesized ferrihydrite nanoparticles with human serum transferrin: Insights from fluorescence spectroscopic studies
Место публикации : Int. J. Mol. Sci. - 2021. - Vol. 22, Is. 13. - Ст.7034. - ISSN 16616596 (ISSN), DOI 10.3390/ijms22137034
Примечания : Cited References: 39. - The work was accomplished with the financial support of the RO-JINR Projects No. 365/11.05.2021, items 8, 87 and 98 and respectivelly, No. 366/11.05.2021, items 7, 86 and 97
Аннотация: Human serum transferrin (HST) is a glycoprotein involved in iron transport that may be a candidate for functionalized nanoparticles to bind and target cancer cells. In this study, the effects of the simple and doped with cobalt (Co) and copper (Cu) ferrihydrite nanoparticles (Fh-NPs, Cu-Fh-NPs, and Co-Fh-NPs) were studied by spectroscopic and molecular approaches. Fluorescence spectroscopy revealed a static quenching mechanism for all three types of Fh-NPs. All Fh-NPs interacted with HST with low affinity, and the binding was driven by hydrogen bonding and van der Waals forces for simple Fh-NPs and by hydrophobic interactions for Cu-Fh-NPs and Co-Fh-NPs binding, respectively. Of all samples, simple Fh-NPs bound the most to the HST binding site. Fluorescence resonance energy transfer (FRET) allowed the efficient determination of the energy transfer between HST and NPs and the distance at which the transfer takes place and confirmed the mechanism of quenching. The denaturation of the HST is an endothermic process, both in the case of apo HST and HST in the presence of the three types of Fh-NPs. Molecular docking studies revealed that Fh binds with a low affinity to HST (Ka = 9.17 × 103 M−1) in accord with the fluorescence results, where the interaction between simple Fh-NPs and HST was described by a binding constant of 9.54 × 103 M−1.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stolyar S. V., Kolenchukova, Oksana A., Boldyreva, Anna V., Kudryasheva, Nadezda S., Gerasimova Yu. V., Krasikov A. A., Yaroslavtsev R. N., Bayukov O. A., Ladygina, Valentina P., Birukova, Elena A.
Заглавие : Biogenic ferrihydrite nanoparticles: Synthesis, properties in vitro and in vivo testing and the concentration effect
Коллективы : Russian Foundation for Basic ResearchRussian Foundation for Basic Research (RFBR); Government of the Krasnoyarsk Territory; Regional Science Foundation [20-416-242907]
Место публикации : Biomedicines. - 2021. - Vol. 9, Is. 3. - Ст.323. - ISSN 2227-9059(eISSN), DOI 10.3390/biomedicines9030323
Примечания : Cited References: 52. - This research was funded by the Russian Foundation for Basic Research, the Government of the Krasnoyarsk Territory and the Regional Science Foundation, grant number 20-416-242907
Аннотация: 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.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Krasikov A. A., Balaev A. D., Stolyar S. V., Ladygina V. P., Iskhakov R. S.
Заглавие : Features of relaxation of the remanent magnetization of antiferromagnetic nanoparticles by the example of ferrihydrite
Место публикации : Phys. Solid State. - 2020. - Vol. 62, Is. 7. - P.1172-1178. - ISSN 10637834 (ISSN), DOI 10.1134/S1063783420070033
Примечания : Cited References: 53
Аннотация: The relaxation of the remanent magnetization of antiferromagnetically ordered ferrihydrite nanoparticles at the exchange bias effect implemented in these systems has been investigated. The magnetization relaxation depends logarithmically on time, which is typical of the thermally activated hoppings of particle magnetic moments through the potential barriers caused by the magnetic anisotropy. The barrier energy obtained by processing of the remanent magnetization relaxation data under the field cooling conditions significantly exceeds the barrier energy under standard (zero field cooling) conditions. The observed difference points out the possibility of using the remanent magnetization relaxation to analyze the mechanisms responsible for the exchange bias effect in antiferromagnetic nanoparticles and measure the parameters of the exchange coupling of magnetic subsystems in such objects.
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