Valeria Rodionova

Hybrid magnetic–plasmonic nanoparticles offer a promising platform for cancer therapy by combining localized photothermal heating with nanoscale mechanical stimulation under remote laser irradiation and low-frequency alternating magnetic fields. However, the therapeutic potential of combining these effects remains insufficiently explored. In this study, we investigated the individual and combined effects of photothermal therapy (PTT) and magnetomechanical therapy (MMT) on the viability of Huh7 hepatocarcinoma cells in vitro using two types of layered Au–Fe microdisks (~1000 nm in diameter) with different layer sequences, i.e., Au(10)/Fe(70)/Au(10) (AFA) and Fe(50)/Au(10)/Fe(50) (FAF), where the values in parentheses denote the layer thicknesses in nanometers. The photothermal conversion efficiencies of the AFA and FAF microdisks in agarose were 35% and 53%, respectively, exceeding the values measured in aqueous solutions. After 24 h of incubation, both types of microdisks exhibited low intrinsic cytotoxicity up to concentrations of 100 µg/mL, at which the cell viability was reduced by no more than 7%. Application of either PTT or MMT enhanced cytotoxicity for both microdisk types. PTT was more effective for AFA microdisks, resulting in 29% cell death, whereas MMT showed greater efficacy for FAF microdisks, inducing 17% cell death. Notably, simultaneous PTT and MMT produced the strongest and synergistic therapeutic effect, leading to approximately 50% cell death. These findings demonstrate the potential of hybrid Au–Fe microdisks as multifunctional agents for combined photothermal and magnetomechanical cancer therapy.

This study systematically investigates how ligands on CoFe2O4 nanoparticles controls magnetoelectric (ME) performance of poly(vinylene fluoride) (PVDF) based multiferroic composites and modulate the behavior of mesenchymal stem cells (MSCs) cultured on these surfaces. Particles bearing different organic coatings (polyethylene glycol, oleylamine, oleic acid, citric acid, and uncoated) were incorporated in a PVDF matrix and characterized by nanoparticle dispersion, interfacial coupling, bulk and local ME response, and magnetically mediated effects on adherent cells. Bulk ME coefficients ranged from 10 to 38 mV·cm⁻¹·Oe⁻¹ for oleic acid and oleylamine coated particles, respectively, a variation attributable to differences in dispersion and polymer–filler coupling. Localized surface measurements revealed signals up to 6000 mV·cm⁻¹·Oe⁻¹ in oleic acid films, consistent with nanoparticle aggregation and surface-localized piezoactive spherulites. Both oleylamine- and oleic acid–containing composites induced MSCs condensation under ME stimulation but only composite with oleylamine enhanced density of adherent cells. These findings delineate coating-dependent mechanisms for tuning ME outputs and provide concrete design criteria for flexible biocompatible ME scaffolds.

The advancement of water electrolysis is hindered by the scarcity of electrocatalysts that integrate high activity, rapid mass transport, and energy‐efficient operation modes. We address this challenge via a versatile room‐temperature synthesis using a liquid NaK alloy as a dual‐function reagent to fabricate porous, multiphase Fe/Co/Ni‐based magnetic electrocatalysts. This method eliminates high‐temperature calcination and toxic etchants, enabling facile scaling with yields > 80% and efficient solvent recovery. The resulting amorphous materials feature mesoporosity (up to 101 m ² /g) and a synergistic mix of metallic and oxide phases. They demonstrate exceptional oxygen evolution reaction (OER) performance, with the Fe‐Co‐based catalyst achieving a low overpotential of 243 mV at 10 mA/cm ² with a Tafel slope of 57 mV/dec and a high current density of 20 mA/cm ² ·mg under an external magnetic field (250 mT). Crucially, the amorphous structure outperforms its crystalline counterpart, and the performance enhancement under a magnetic field is primarily driven by magnetohydrodynamic effects amplified by the material's porous architecture. This work establishes a sustainable platform for designing next‐generation electrocatalysts where structural complexity is engineered to overcome intrinsic limitations in energy conversion.

This paper explores the potential of amorphous and nanocrystalline glass-coated microwires as highly versatile, miniaturized sensing elements, leveraging their intrinsic nonlinear magnetization dynamics. In magnetic systems, this approach is particularly advantageous because the degree of nonlinearity can be externally tuned using stimuli such as applied magnetic fields, mechanical stress, or temperature variations. From this context, we summarize key properties of microwires—including bistability, a specific easy magnetization direction, internal stress distributions, and magnetostriction—that can be tailored through composition and annealing. In this review, we compare for the first time two key contactless readout methodologies: (i) time-domain detection of the switching field and (ii) frequency-domain harmonic analysis of the induced voltage. These principles have been successfully applied to a broad range of practical sensors, including devices for monitoring mechanical stress in structural materials, measuring temperature in biomedical settings, and detecting magnetic particles. Together, these advances highlight the potential of microwires for embedded, wireless sensing in both engineering and medical applications.

This study systematically investigates how ligands on CoFe ₂ O ₄ nanoparticles control the magnetoelectric (ME) performance of poly(vinylidene fluoride) (PVDF)-based multiferroic composites and modulate the behavior of mesenchymal stem cells (MSCs) cultured on these surfaces. Particles bearing different organic coatings (polyethylene glycol, oleylamine, oleic acid, citric acid, and uncoated) were incorporated into a PVDF matrix and characterized by nanoparticle dispersion, interfacial coupling, bulk and local ME response, and magnetically mediated effects on adherent cells. Bulk ME coefficients ranged from 10 to 38 mV cm ⁻¹ Oe ⁻¹ for oleic acid- and oleylamine-coated particles, respectively, a variation attributable to differences in dispersion and polymer–filler coupling. Localized surface measurements revealed signals up to 6,000 mV cm ⁻¹ Oe ⁻¹ in oleic acid-containing films, consistent with nanoparticle aggregation and surface-localized piezoactive spherulites. Both oleylamine- and oleic acid-containing composites induced the formation of densely packed mesenchymal stem cell aggregates, morphologically resembling mesenchymal condensation under ME stimulation, but only the oleylamine-containing composite enhanced the density of adherent cells. These findings delineate coating-dependent mechanisms for tuning ME outputs and provide concrete design criteria for flexible biocompatible ME scaffolds.

In this paper, we have investigated piezoelectric, magnetic and magnetoelectric properties of composite materials, consisting of polyvinylidene fluoride (PVDF) matrix and CoFe ₂ O ₄ nanoparticles in the form of filament extrusion and 3D printed films. We used PVDF powders from different manufacturers each with different molecular weights and phase compositions. For PVDF with lower molecular weight and higher electroactive phase content of the, we observed that approximately 80 % of the electroactive phase in the starting polymer was effectively transferred to the printed films through all technological stages. The composite filaments exhibited ferromagnetic behavior with a large coercive force of 1.7±0.1 kOe consistent with a particle size of about 20 nm. The magnetoelectric coefficient was about 2 mV/(Oe∙cm) for printed composite films from both precursors, which is sufficient for a range of applications including microelectronics and tissue engineering using magnetically stimulated electric fields.

Anisotropic ferromagnetic micro- and nanoparticles made of 3d metals demonstrate the ability to effectively influence micro- and nanoscale biological entities through hyperthermia and mechanical vibrations induced by magnetic fields. Multifunctional nanoparticles designed for combined therapies are particularly effective. This study explores the potential application of Ni@Au nanotubes to synergize magnetomechanical effects with photothermal heating. The orientation of nanotubes in a magnetic field was demonstrated by changes in the intensity of the light beam passing through a water suspension of nanotubes. The gold coating doubled the optical absorption of the solution in comparison with pure nickel nanotubes and resulted in the appearance of a resonance-enhanced peak in the range of 700–800 nm, the position of which is in accordance with theoretical calculations. The photothermal performance of nanotube solu-tions was quantitatively assessed by determining the photothermal conversion coefficient, which increased due to gold coating. However, it’s worth noting that the gold coating did not significantly reduce nanotube cytotoxicity in hepatocyte-derived cellular carcinoma cells (Huh7). The potential reasons for this outcome include the large particle size and non-uniform gold coating. Nevertheless, the combination of two anti-cancer therapies employing the same type of particles offers the opportunity to reduce particle concentration while maintaining the required therapeutic efficacy.

Two-layered structures consisting of piezopolymer and magnetic elastomer were investigated as magnetoelectric material. Three types of magnetic elastomer based on cobalt ferrite (CoFe₂O₄) and Ni- or Zn-substituted CoFe₂O₄ nanoparticles were used as magnetically sensitive layers. Cobalt ferrite nanoparticles are considered one of the most promising metal-oxide nanomaterials because of their favorable magnetic properties, such as high saturation magnetization and magnetic anisotropy. The substitution of Co²⁺ in cobalt ferrite with other transition metals allows for additional tailoring of these properties. The modified magnetic behavior of the substituted CoFe₂O₄ nanoparticles directly influenced the magnetic properties of magnetic elastomers and, consequently, the magnetoelectric response of composite structures. In this case, the resonant frequency of the magnetoelectric effect remained largely independent of the type of magnetic nanoparticles in the magnetic elastomer layer but its magnitude increased upon Zn substitution up to ~107 mV·cm⁻¹·Oe⁻¹. These findings highlight the potential of chemically engineered magnetic properties of CoFe₂O₄ nanoparticles for manufacturing magnetoelectric composites to expand their applications in energy harvesting and sensors.

Amorphous magnetic alloys are now widely used in electronics, electrical engineering, robotics, sensors, etc. They are mainly used in the form of wires, tapes and foils. The technology of manufacturing products from amorphous magnetic alloys is constantly improving and new methods are being implemented. In our work, microspirals (microsprings) made from amorphous microwires are studied. Measurements of hysteresis loops for different types of microspirals have been carried out and the relationship between the hysteresis anisotropy and the parameters of the spirals is discussed. Special attention is given to the study of the magnetic impedance. It is found that the field dependence of the impedance of microspirals is asymmetric, and the sign of the asymmetry is related to the chirality of the spirals. The possibility of using amorphous magnetic microspirals for the development of sensor and microrobotic elements is discussed.

We report a comprehensive investigation of Cu(II) and Pb(II) ion sorption kinetics on magnetically functionalized Ti₃C₂T_x MXene composites. The composite material was synthesized by functionalizing multilayer MXenes with iron oxide nanoparticles through a co-precipitation method, resulting in a magnetic sorbent with a saturation magnetization of 32 ± 3 A m²/kg. The experimental data were analyzed using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The sorption process for both metal ions followed pseudo-second-order kinetics (R² > 0.99), with activation energies of –61.5 and ‒24.8 kJ/mol for Cu(II) and Pb(II), respectively. The analysis revealed that Cu(II) sorption involves both chemical interactions with functional groups and diffusion processes, while Pb(II) sorption is primarily diffusion-controlled. External diffusion rates were found to be an order of magnitude higher than internal diffusion rates for both metal ions, suggesting that the 2D structure of MXenes may influence the intraparticle diffusion of heavy metals. The magnetic functionalization enables efficient separation of the sorbent after treatment, making this composite material promising for heavy metal removal applications in water treatment processes.