Ferromagnetic resonance spectra of linear magnetosome chains

• Elizaveta M. Gubanova and
• Nikolai A. Usov

Beilstein J. Nanotechnol. 2024, 15, 157–167, doi:10.3762/bjnano.15.15

• superparamagnetic nanoparticles in ac magnetic field H1(t), it is convenient to rewrite Equation 7 in the form of the time-averaged integral where Δt is a certain time interval significantly exceeding the period of oscillations of the ac magnetic field, τ = 2π/ω. Using the small amplitude of the ac magnetic field

Two-step single-reactor synthesis of oleic acid- or undecylenic acid-stabilized magnetic nanoparticles by thermal decomposition

• Mykhailo Nahorniak,
• Pamela Pasetto,
• Jean-Marc Greneche,
• Volodymyr Samaryk,
• Sandy Auguste,
• Anthony Rousseau,
• Nataliya Nosova and
• Serhii Varvarenko

Beilstein J. Nanotechnol. 2023, 14, 11–22, doi:10.3762/bjnano.14.2

• reduction of nanoparticle diameter below the critical size of 25 nm leads to nanoparticles with superparamagnetic properties [10][11]. Due to the absence of coercive forces in superparamagnetic nanoparticles not exposed to an external magnetic field, they are characterized by good colloidal stability, which

Recent progress in magnetic applications for micro- and nanorobots

• Ke Xu,
• Shuang Xu and
• Fanan Wei

Beilstein J. Nanotechnol. 2021, 12, 744–755, doi:10.3762/bjnano.12.58

• used in medical MNRs [26]. For example, based on the combination of copolymer brushes and superparamagnetic nanoparticles, a biomimetic nanoreactor was proposed. It contained a magnetic field-responsive catalytic system, namely magnetic field-responsive binary deoxyribozyme (MaBiDZ) [27]. Also, it

• understanding magnetic MNR swarms, and further applications may be found. Bakshi et al. [27] reported a magnetic field-responsive catalytic system based on superparamagnetic nanoparticles [41], namely magnetic field-responsive binary deoxyribozyme (MaBiDZ, Figure 1), which could sense intracellular target mRNA

• field of biomedicine. Ceylan et al. [42] also used superparamagnetic nanoparticles to explore 3D-printed biodegradable [17][24] microrobots. These robots could be used for theranostic cargo delivery and release. Embedding superparamagnetic iron oxide nanoparticles [43] in the form of nanocomposites into

Influence of the magnetic nanoparticle coating on the magnetic relaxation time

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2020, 11, 1207–1216, doi:10.3762/bjnano.11.105

• Abstract Colloidal systems consisting of monodomain superparamagnetic nanoparticles have been used in biomedical applications, such as the hyperthermia treatment for cancer. In this type of colloid, called a nanofluid, the nanoparticles tend to agglomeration. It has been shown experimentally that the

• relaxation time; nanoparticle coating; numerical simulation; stochastic Langevin dynamics method; superparamagnetic nanoparticles; Introduction One of the most important biomedical applications of colloidal magnetic nanoparticle systems is magnetic hyperthermia applied as an alternative for cancer treatment

• that influence the characteristics of the final material [7]. Uncoated superparamagnetic nanoparticles are difficult to synthesise since they are not stable in colloidal suspensions. Therefore, it is challenging to use these nanoparticles in magnetic hyperthermia therapy [8]. By exposing these

Applications of superparamagnetic iron oxide nanoparticles in drug and therapeutic delivery, and biotechnological advancements

• Maria Suciu,
• Corina M. Ionescu,
• Alexandra Ciorita,
• Septimiu C. Tripon,
• Dragos Nica,
• Hani Al-Salami and
• Lucian Barbu-Tudoran

Beilstein J. Nanotechnol. 2020, 11, 1092–1109, doi:10.3762/bjnano.11.94

• SPIONs smaller than 10 nm, by Néel and Brownian relaxation for SPIONs between 10 and 13 nm (mechanisms in superparamagnetic nanoparticles), and by hysteresis loss for larger SPIONs (mechanism of ferromagnetic nanoparticles) [139]. Hyperthermia potential and efficacy of SPIONs depend on their structure

Dynamics of superparamagnetic nanoparticles in viscous liquids in rotating magnetic fields

• Nikolai A. Usov,
• Ruslan A. Rytov and
• Vasiliy A. Bautin

Beilstein J. Nanotechnol. 2019, 10, 2294–2303, doi:10.3762/bjnano.10.221

• director are distinguished depending on frequency and amplitude of the rotating magnetic field. The specific absorption rate of a dilute assembly of superparamagnetic nanoparticles in rotating magnetic field is calculated by solving the Landau–Lifshitz stochastic equation for the unit magnetization vector

• ]. Unfortunately, the specific absorption rate (SAR) measured in RMFs [41][43] for assemblies of particles distributed in a viscous liquid turned out to be very small, of the order of a few watts per gram of magnetic material. At the same time, the SAR of an assembly of superparamagnetic nanoparticles in AMF under

• SAR of a dilute assembly of superparamagnetic nanoparticles in RMFs is calculated by solving the Landau–Lifshitz stochastic equation for the unit magnetization vector and the stochastic equation for the particle director. It is shown that at elevated frequencies, f > 100 kHz, there is an optimal range

On the relaxation time of interacting superparamagnetic nanoparticles and implications for magnetic fluid hyperthermia

• Andrei Kuncser,
• Nicusor Iacob and
• Victor E. Kuncser

Beilstein J. Nanotechnol. 2019, 10, 1280–1289, doi:10.3762/bjnano.10.127

• superparamagnetic nanoparticles on the specific absorption rate of ferrofluids, through susceptibility loss mechanisms, are discussed. Various models supporting the influence of interparticle interactions on the relaxation time are reviewed, leading to the conclusion that they are controversial, not versatile

Tailoring the magnetic properties of cobalt ferrite nanoparticles using the polyol process

• Malek Bibani,
• Romain Breitwieser,
• Alex Aubert,
• Vincent Loyau,
• Silvana Mercone,
• Souad Ammar and
• Fayna Mammeri

Beilstein J. Nanotechnol. 2019, 10, 1166–1176, doi:10.3762/bjnano.10.116

• is that of ferrite particles in their single magnetic domain state. As it is summarized in Table 2, quite all the samples showed very high TB values (>300 K). The only superparamagnetic nanoparticles at room temperature are the stoichiometric particles synthesized in TriEG for 6 h (Co-1-TriEG-6). In

Influence of dielectric layer thickness and roughness on topographic effects in magnetic force microscopy

• Alexander Krivcov,
• Jasmin Ehrler,
• Marc Fuhrmann,
• Tanja Junkers and
• Hildegard Möbius

Beilstein J. Nanotechnol. 2019, 10, 1056–1064, doi:10.3762/bjnano.10.106

• coupling can be tuned and minimized for thick layers. Using the theory of capacitive coupling and the magnetic point dipole–dipole model we could theoretically explain and experimentally prove the phase signal for single superparamagnetic nanoparticles as a function of the layer thickness of the dielectric

• small SPIONs aggregates by capacitive coupling effects. In order to distinguish electrostatic and magnetic forces Angeloni et al. [18] employed a controlled change of the tip magnetization. They demonstrated this new method by measuring superparamagnetic nanoparticles but also discussed current

• magnetic field of the probe with a magnetic moment of 3·10−16 A·m2 is sufficient to induce a magnetic moment at lift heights up to 150 nm in superparamagnetic nanoparticles with 10 nm diameter. This results in attractive forces and, thus, negative phase shifts in MFM measurements. Therefore the magnetic

Magnetic field-assisted assembly of iron oxide mesocrystals: a matter of nanoparticle shape and magnetic anisotropy

• Julian J. Brunner,
• Marina Krumova,
• Helmut Cölfen and
• Elena V. Sturm (née Rosseeva)

Beilstein J. Nanotechnol. 2019, 10, 894–900, doi:10.3762/bjnano.10.90

• superparamagnetic nanoparticles and how a magnetic field can be used to design anisotropic mesocrystals with different structures. Keywords: directed assembly; magnetite; mesocrystal; nanoparticle; transmission electron microscopy; Findings In materials science, nanoparticles and their assemblies belong to the

• mesocrystals” were analysed and have shown the same structural variation as described above. These structural features of “directed mesocrystals” indicate that complex interactions between anisotropically shaped superparamagnetic nanoparticles occur during the assembly processes under an external magnetic

• without the external magnetic field. It is shown that the morphology and magnetic properties of the superparamagnetic nanoparticles are crucial for understanding the packing arrangement and the orientational order in superlattices. Furthermore, the magnetic field restricts the diffusion of nanoparticles

Heating ability of magnetic nanoparticles with cubic and combined anisotropy

• Nikolai A. Usov,
• Mikhail S. Nesmeyanov,
• Elizaveta M. Gubanova and
• Natalia B. Epshtein

Beilstein J. Nanotechnol. 2019, 10, 305–314, doi:10.3762/bjnano.10.29

• of the properties of interacting assemblies of superparamagnetic nanoparticles with uniaxial anisotropy. In the present manuscript the same approach is used to study the behavior of dense clusters of magnetite nanoparticles with cubic or combined anisotropy. The stochastic LL equation [22][28][29][30

• magneto–dipole interactions and the effect of thermal fluctuations. For an assembly of superparamagnetic nanoparticles with uniaxial anisotropy, it has been recently shown [22] that the existence of nonmagnetic shells of appreciable thickness at the nanoparticle surface considerably reduces the intensity

Nanocomposites comprised of homogeneously dispersed magnetic iron-oxide nanoparticles and poly(methyl methacrylate)

• Sašo Gyergyek,
• David Pahovnik,
• Ema Žagar,
• Alenka Mertelj,
• Rok Kostanjšek,
• Miloš Beković,
• Marko Jagodič,
• Heinrich Hofmann and
• Darko Makovec

Beilstein J. Nanotechnol. 2018, 9, 1613–1622, doi:10.3762/bjnano.9.153

• the superparamagnetic state is observed. Above a certain critical temperature, called the blocking temperature, the thermal energy induces rapid fluctuations of the nanoparticle’s magnetic moment relative to the time of observation [1][2]. Superparamagnetic nanoparticles do not show remanence and

Anchoring Fe₃O₄ nanoparticles in a reduced graphene oxide aerogel matrix via polydopamine coating

• Błażej Scheibe,
• Radosław Mrówczyński,
• Natalia Michalak,
• Karol Załęski,
• Michał Matczak,
• Mateusz Kempiński,
• Zuzanna Pietralik,
• Mikołaj Lewandowski,
• Stefan Jurga and
• Feliks Stobiecki

Beilstein J. Nanotechnol. 2018, 9, 591–601, doi:10.3762/bjnano.9.55

• susceptibility curves coincide at high temperatures and separate as the temperature is decreasing. The maximum of the ZFC curve is defined as the blocking temperature (TB) of the superparamagnetic nanoparticles and the width of the ZFC curve maximum is related to the size distribution or agglomeration process of

• superparamagnetic nanoparticles. The TB determined for the rGO-Fe3O4 (Figure S5 in Supporting Information File 1) and rGO-PDA@Fe3O4 aerogels is very similar – in the range of 215 K < TB < 220 K. This indicates negligible influence of PDA on the magnetic properties of Fe3O4 nanoparticles. The compression of rGO-PDA

Formation and shape-control of hierarchical cobalt nanostructures using quaternary ammonium salts in aqueous media

• Ruchi Deshmukh,
• Anurag Mehra and
• Rochish Thaokar

Beilstein J. Nanotechnol. 2017, 8, 494–505, doi:10.3762/bjnano.8.53

• spherical nanoparticles 150 nm, compared to 8 nm particles under ambient conditions, at initial time suggests that the effectiveness of TMAH to cleave and twin the seeds is lost. The aggregation of untwinned uncoated superparamagnetic nanoparticles results in large spherical nanoclusters, which then

Multiwalled carbon nanotube hybrids as MRI contrast agents

• Nikodem Kuźnik and
• Mateusz M. Tomczyk

Beilstein J. Nanotechnol. 2016, 7, 1086–1103, doi:10.3762/bjnano.7.102

• therefore increasing the resulting relaxivity [36]. On the other hand, superparamagnetic nanoparticles, both in the most common SPIO and in others (e.g., CoFe2O4, CdTe quantum dots), anchored on the nanotube net require an extension of the SBM theory [13][14]. Moreover, the hypothesis of CNT as a conducting

An adapted Coffey model for studying susceptibility losses in interacting magnetic nanoparticles

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2015, 6, 2173–2182, doi:10.3762/bjnano.6.223

• superparamagnetic behaviour [15]. The typical time between two flips is called relaxation time, and the reversal process is called relaxation process. In nanofluids, the superparamagnetic nanoparticles have two associated relaxation processes: the Néel relaxation process and Brownian relaxation process. The former

Hematopoietic and mesenchymal stem cells: polymeric nanoparticle uptake and lineage differentiation

• Ivonne Brüstle,
• Thomas Simmet,
• Gerd Ulrich Nienhaus,
• Katharina Landfester and
• Volker Mailänder

Beilstein J. Nanotechnol. 2015, 6, 383–395, doi:10.3762/bjnano.6.38

• hMSCs have been used in many studies, only a limited number of studies with these cells have been undertaken [1]. Cells labeled with superparamagnetic nanoparticles can be tracked after transplantation using MRI methods [23]. This approach allows for a deeper knowledge about the biological distribution

PEGylated versus non-PEGylated magnetic nanoparticles as camptothecin delivery system

• Paula M. Castillo,
• Mario de la Mata,
• Maria F. Casula,
• José A. Sánchez-Alcázar and
• Ana P. Zaderenko

Beilstein J. Nanotechnol. 2014, 5, 1312–1319, doi:10.3762/bjnano.5.144

• chemotherapeutic agent due to its poor water-solubility and chemical instability and, as a consequence, no effective administration means have been designed. In this work, camptothecin has been successfully loaded into iron oxide superparamagnetic nanoparticles with an average size of 14 nm. It was found that

• ; cancer therapy; iron oxide superparamagnetic nanoparticles; polyethylene glycol; Introduction Camptothecin (CPT) is a quinoline based alkaloid, which exhibits a potent cytotoxic activity against a broad spectrum of tumours [1][2][3]. While most antineoplastic agents inhibit cancer cell proliferation by

• , since an increase of the time during which the cell cultures are incubated with the formulations leads to an increased apoptosis (data not shown). In summary, two new CPT formulations based on iron oxide superparamagnetic nanoparticles have been described and characterized by FTIR. Both formulations

Manipulation of isolated brain nerve terminals by an external magnetic field using D-mannose-coated γ-Fe₂O₃ nano-sized particles and assessment of their effects on glutamate transport

• Tatiana Borisova,
• Natalia Krisanova,
• Arsenii Borуsov,
• Roman Sivko,
• Ludmila Ostapchenko,
• Michal Babic and
• Daniel Horak

Beilstein J. Nanotechnol. 2014, 5, 778–788, doi:10.3762/bjnano.5.90

• in nano-neurotechnology. D-Mannose-coated superparamagnetic nanoparticles were synthesized by coprecipitation of Fe(II) and Fe(III) salts followed by oxidation with sodium hypochlorite and addition of D-mannose. Effects of D-mannose-coated superparamagnetic maghemite (γ-Fe2O3) nanoparticles on key

Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

• Miriam Jaafar,
• Oscar Iglesias-Freire,
• Luis Serrano-Ramón,
• Manuel Ricardo Ibarra,
• Jose Maria de Teresa and
• Agustina Asenjo

Beilstein J. Nanotechnol. 2011, 2, 552–560, doi:10.3762/bjnano.2.59

• technique to detect weak magnetic fields arising from low dimensional complex systems such as organic nanomagnets, superparamagnetic nanoparticles, carbon-based materials, etc. In all these cases, the magnetic nanocomponents and the substrate supporting them present quite different electronic behavior, i.e