Effect of a halogen bond on the crystal structure of terphenyldicarboxylic acid derivatives.

The syntheses and structures of dimethyl [11,21:24,31-terphenyl]-14,34-dicarboxylate (1), dimethyl 22,25-diiodo[11,21:24,31-terphenyl]-14,34-dicarboxylate (2), potassium [11,21:24,31-terphenyl]-14,34-dicarboxylate (3) and dimethyl [1,1'-biphenyl]-4,4'-dicarboxylate (4) are reported. Neighboring phenyl rings in compounds 1, 3 and 4 have a planar structure (torsion angles are 0.6-4.1°) and the molecules are packed into regular layers. In the structure of the iodinated derivative of terphenyldicarboxylic acid (2), the middle benzene ring of the terphenyl fragment is rotated relative to the other rings by 64° due to the repulsion between the protons and the iodine atoms of neighboring rings. The formation of halogen bonds between iodine and oxygen atoms of the carbonyl group leads to the movement of molecules of one layer into another layer and the loss of layered structure. Potassium [11,21:24,31-terphenyl]-14,34-dicarboxylate (3) forms crystals with an ionic structure. The coordination number of the potassium cation is eight and the resulting coordination polyhedron is a distorted square antiprism. Dianions in the potassium salt crystal are packed in layers similar to the layers in the dimethyl ethers 1 and 4. Salt 3 has high thermal stability to 500°C.

Wake-Up Free Ultrathin Ferroelectric Hf0.5Zr0.5O2 Films.

The development of the new generation of non-volatile high-density ferroelectric memory requires the utilization of ultrathin ferroelectric films. The most promising candidates are polycrystalline-doped HfO2 films because of their perfect compatibility with silicon technology and excellent ferroelectric properties. However, the remanent polarization of HfO2 films is known to degrade when their thickness is reduced to a few nanometers. One of the reasons for this phenomenon is the wake-up effect, which is more pronounced in the thinner the film. For the ultrathin HfO2 films, it can be so long-lasting that degradation occurs even before the wake-up procedure is completed. In this work, an approach to suppress the wake-up in ultrathin Hf0.5Zr0.5O2 films is elucidated. By engineering internal built-in fields in an as-prepared structure, a stable ferroelectricity without a wake-up effect is induced in 4.5 nm thick Hf0.5Zr0.5O2 film. By analysis of the functional characteristics of ferroelectric structures with a different pattern of internal built-in fields and their comparison with the results of in situ piezoresponse force microscopy and synchrotron X-ray micro-diffraction, the important role of built-in fields in ferroelectricity of ultrathin Hf0.5Zr0.5O2 films as well as the origin of stable ferroelectric properties is revealed.

Preparation, phase stability, and magnetization behavior of high entropy hexaferrites.

The polycrystalline SrFe12O19 samples deeply substituted up to at.67% by Al3+, Ga3+, In3+, Co3+, and Cr3+ cations with a high configurational mixing entropy were prepared by solid-phase synthesis. Phase purity and unit cell parameters were obtained from XRD and analyzed versus the average ionic radius of the iron sublattice. The crystallite size varied around ∼4.5 µm. A comprehensive study of the magnetization was realized in various fields and temperatures. The saturation magnetization was calculated using the Law of Approach to Saturation. The accompanying magnetic parameters were determined. The magnetic crystallographic anisotropy coefficient and the anisotropy field were calculated. All investigated magnetization curves turned out to be nonmonotonic. The magnetic ordering and freezing temperatures were extracted from the ZFC and FC curves. The average size of magnetic clusters varied around ∼350 nm. The high values of the configurational mixing entropy and the phenomenon of magnetic dilution were taken into account.

The Interrelation of Synthesis Conditions and Wettability Properties of the Porous Anodic Alumina Membranes.

The results of studies on the wettability properties and preparation of porous anodic alumina (PAA) membranes with a 3.3 ± 0.2 µm thickness and a variety of pore sizes are presented in this article. The wettability feature results, as well as the fabrication processing characteristics and morphology, are presented. The microstructure effect of these surfaces on wettability properties is analyzed in comparison to outer PAA surfaces. The interfacial contact angle was measured for amorphous PAA membranes as-fabricated and after a modification technique (pore widening), with pore sizes ranging from 20 to 130 nm. Different surface morphologies of such alumina can be obtained by adjusting synthesis conditions, which allows the surface properties to change from hydrophilic (contact angle is approximately 13°) to hydrophobic (contact angle is 100°). This research could propose a new method for designing functional surfaces with tunable wettability. The potential applications of ordinary alumina as multifunctional films are demonstrated.

Reprogrammable Soft Swimmers for Minimally Invasive Thrombus Extraction.

Thrombosis-related diseases are the primary cause of death in the world. Despite recent advances in thrombosis treatment methods, their invasive nature remains a crucial factor, which leads to considerable deadly consequences. Soft magnetic robots are attracting widespread interest due to their fast response, remote actuation, and shape reprogrammability and can potentially avoid the side effects of conventional approaches. This paper outlines a new approach to the thrombosis treatment via reprogrammable magnetic soft robots that penetrate, hook, and extract the plasma clots in a vein-mimicking system under applied rotating magnetic fields. We present shape-switching bioinspired soft swimmers, capable of locomotion by different mechanisms in vein-mimicking flow conditions and whose swimming efficiency is similar to animals. Further, we demonstrate the potential of a developed robot for minimally invasive thromboextraction with and without fibrinolytic usage, including hooking the plasma clot for 3.1 ± 1.1 min and extracting it from the vein-mimicking system under the applied magnetic fields. We consider an interesting solution for thrombosis treatment to avoid substantial drawbacks of the existing methods.

Creation and Magnetic Study of Ferrites with Magnetoplumbite Structure Multisubstituted by Al3+, Cr3+, Ga3+, and In3+ Cations.

Multisubstituted barium ferrites with a magnetoplumbite structure were obtained by the method of solid-phase reactions with ferritization and pre-firing. Three-charged, mainly diamagnetic cations Al3+, Cr3+, Ga3+, and In3+ were chosen as substituents for the Fe3+ iron cations, the proportion of which in solid solutions did not exceed 50%. The values of the configurational mixing entropy were calculated for all the compositions. A slight deviation of the chemical composition of the obtained solid solutions from the nominal value was established by the energy-dispersive X-ray spectroscopy method. The phase purity and values of the unit cell parameters were refined from X-ray scattering data using full-profile analysis in the Rietveld method. A non-monotonic behavior of the unit cell parameters as a function of the B-sub-lattice average ionic radius of the magnetoplumbite structure was found. A minimum unit cell volume of ~667.15 Å3 was found for the composition BaFe6.11Al1.56Cr2.17Ga2.16O19 with a B-sub-lattice average ionic radius of ~7.449 Å. The average crystallite size varied within 5.5-6.5 µm. The temperature and field dependencies of the magnetization have been measured. The values of the saturation magnetization, residual magnetization, hysteresis loop squareness, and coercivity at 50 K and 300 K were extracted from the experimental data. Using the Law of Approach to Saturation, the magnetic crystallographic anisotropy coefficient and anisotropy field were calculated. Multisubstitution leads to a significant decrease in such magnetic parameters as the magnetic ordering temperature and spontaneous magnetization at both temperatures. The maximum magnetic ordering temperature of ~297.7 K was found for the composition BaFe5.84Ga6.19O19 with a B-sub-lattice average ionic radius of ~7.586 Å in a field of 500 Oe. A maximum saturation magnetization of ~24.7 emu/g was found for the composition BaFe5.84Ga6.19O19 with a B-sub-lattice average ionic radius of ~7.586 Å at 50 K. A maximum hysteresis loop squareness of ~0.72 was found for the composition BaFe6.11Al1.56Cr2.17Ga2.16O19 with an average ionic radius of ~7.449 Å at 50 K. A maximum magnetic crystallographic anisotropy coefficient of ~2.09 × 105 Erg/g was found for the composition BaFe6.19Al1.25Cr1.57Ga1.74In1.26O19 with a B-sub-lattice average ionic radius of ~7.706 Å at 50 K. The frustrated magnetic state including the nano-sized clusters with an average diameter in the range of 50-200 nm was established from the results of measuring the ZFC and FC temperature magnetizations. The interpretation of the obtained experimental data is carried out taking into account the increased stability of high-entropy phases and regular changes in the intensity of the Fe3+(Al3+, Cr3+, Ga3+, In3+)-O2--Fe3+(Al3+, Cr3+, Ga3+, In3+) indirect superexchange interactions as a result of magnetic dilution of the iron sub-lattice in the magnetoplumbite structure.

Hierarchical Porous Magnetite Structures: From Nanoparticle Assembly to Monolithic Aerogels.

The development of universal methods to synthesize materials with different structures is always in the researchers' focus. Despite the fact that various structures based on magnetite have already been obtained, synthetic approaches that allow to synthesize materials with a wide range of texture and functional properties are still very poorly presented. In this work, we demonstrate that a stable magnetite hydrosol can be easily converted into monolithic structures of xero-, cryo- and aerogel by careful varying concentrations and drying conditions. We have also theoretically explained the observed effects by studying the percolation threshold at the sol-gel transition by means of controlled assembly of magnetite nanoparticles. At the calculated percolation point three types of materials different in porous organization were obtained. Due to the high biocompatibility of magnetite nanoparticles, the materials obtained were evaluated for cytotoxicity on HeLa cells line. All synthesized magnetite structures show excellent biocompatibility and minor cytotoxic effects at concentrations up to 1 µg mL-1. Considering that the porosity of materials can influence the manifestation of the hemostatic effect, whole-blood clotting study revealed the hemostatic potential of magnetite aerogel. That fact can be explained by presence spongy structure of the aerogel that allowed blood to be rapidly absorbed through full contact.

Magnetic Properties of the Densely Packed Ultra-Long Ni Nanowires Encapsulated in Alumina Membrane.

High-quality and compact arrays of Ni nanowires with a high ratio (up to 700) were obtained by DC electrochemical deposition into porous anodic alumina membranes with a distance between pores equal to 105 nm. The nanowire arrays were examined using scanning electron microscopy, X-ray diffraction analysis and vibration magnetometry at 300 K and 4.2 K. Microscopic and X-ray diffraction results showed that Ni nanowires are homogeneous, with smooth walls and mostly single-crystalline materials with a 220-oriented growth direction. The magnetic properties of the samples (coercivity and squareness) depend more on the length of the nanowires and the packing factor (the volume fraction of the nanowires in the membrane). It is shown that the dipolar interaction changes the demagnetizing field during a reversal magnetization of the Ni nanowires, and the general effective field of magnetostatic uniaxial shape anisotropy. The effect of magnetostatic interaction between ultra-long nanowires (with an aspect ratio of >500) in samples with a packing factor of ≥37% leads to a reversal magnetization state, in which a "curling"-type model of nanowire behavior is realized.

Shape anisotropic magnetic thrombolytic actuators: synthesis and systematic behavior study.

Thrombosis-related diseases are undoubtedly the deadliest disorders. During the last decades, numerous attempts were made to reduce the overall death rate and severe complications caused by treatment delays. Significant progress has been made in the development of nanostructured thrombolytics, especially magnetically controlled. The emergence of thrombolytic magnetic actuators, which can deliver tPA to the occlusion zone and perform mechanical disruption of the fibrin network under the application of a rotating magnetic field (RMF), can be considered for the next generation of thrombolytic drugs. Thus, we propose a systematic study of magnetic-field mediated mechanically-assisted thrombolysis (MFMMAT) for the first time. Four types of magnetic particles with different morphology and dimensionality were utilized to assess their impact on model clot lysis under different RMF parameters. Chain-like 1D and sea urchins-like 3D structures were found to be the most effective, increasing thrombolysis efficacy to nearly 200%. The drastic difference was also observed during the dissolution of 3 days old blood clots. Pure plasminogen activator had almost no effect on clot structure during 30 minutes of treatment while applying MFMMAT led to the significant decrease of clot area, thus uncovering the possibility of deep venous thrombosis therapy.

Polysubstituted High-Entropy [LaNd](Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3 Perovskites: Correlation of the Electrical and Magnetic Properties.

La-, Nd- and La/Nd-based polysubstituted high-entropy oxides (HEOs) were produced by solid-state reactions. Composition of the B-site was fixed for all samples (Cr0.2Mn0.2Fe0.2Co0.2Ni0.2) with varying of A-site cation (La, Nd and La0.5Nd0.5). Nominal chemical composition of the HEOs correlates well with initial calculated stoichiometry. All produced samples are single phase with perovskite-like structure. Average particle size is critically dependent on chemical composition. Minimal average particle size (~400 nm) was observed for the La-based sample and maximal average particle size (5.8 µm) was observed for the Nd-based sample. The values of the configurational entropy of mixing for each sample were calculated. Electrical properties were investigated in the wide range of temperatures (150-450 K) and frequencies (10-1-107 Hz). Results are discussed in terms of the variable range hopping and the small polaron hopping mechanisms. Magnetic properties were analyzed from the temperature and field dependences of the specific magnetization. The frustrated state of the spin subsystem was observed, and it can be a result of the increasing entropy state. From the Zero-Field-Cooling and Field-Cooling regimes (ZFC-FC) curves, we determine the average and Smax maximum size of a ferromagnetic nanocluster in a paramagnetic matrix. The average size of a ferromagnetic cluster is ~100 nm (La-CMFCNO) and ~60 nm (LN-CMFCNO). The Smax maximum size is ~210 nm (La-CMFCNO) and ~205 nm (LN-CMFCNO). For Nd-CMFCNO, spin glass state (ferromagnetic cluster lower than 30 nm) was observed due to f-d exchange at low temperatures.

A-Site Cation Size Effect on Structure and Magnetic Properties of Sm(Eu,Gd)Cr0.2Mn0.2Fe0.2Co0.2Ni0.2O3 High-Entropy Solid Solutions.

Three high-entropy Sm(Eu,Gd)Cr0.2Mn0.2Fe0.2Co0.2Ni0.2O3 perovskite solid solutions were synthesized using the usual ceramic technology. The XRD investigation at room temperature established a single-phase perovskite product. The Rietveld refinement with the FullProf computer program in the frame of the orthorhombic Pnma (No 62) space group was realized. Along with a decrease in the V unit cell volume from ~224.33 Å3 for the Sm-based sample down to ~221.52 Å3 for the Gd-based sample, an opposite tendency was observed for the unit cell parameters as the ordinal number of the rare-earth cation increased. The average grain size was in the range of 5-8 µm. Field magnetization was measured up to 30 kOe at 50 K and 300 K. The law of approach to saturation was used to determine the Ms spontaneous magnetization that nonlinearly increased from ~1.89 emu/g (Sm) up to ~17.49 emu/g (Gd) and from ~0.59 emu/g (Sm) up to ~3.16 emu/g (Gd) at 50 K and 300 K, respectively. The Mr residual magnetization and Hc coercive force were also determined, while the SQR loop squareness, k magnetic crystallographic anisotropy coefficient, and Ha anisotropy field were calculated. Temperature magnetization was measured in a field of 30 kOe. ZFC and FC magnetization curves were fixed in a field of 100 Oe. It was discovered that the Tmo magnetic ordering temperature downward-curve decreased from ~137.98 K (Sm) down to ~133.99 K (Gd). The spin glass state with ferromagnetic nanoinclusions for all the samples was observed. The average and Dmax maximum diameter of ferromagnetic nanoinclusions were calculated and they were in the range of 40-50 nm and 160-180 nm, respectively. The mechanism of magnetic state formation is discussed in terms of the effects of the A-site cation size and B-site poly-substitution on the indirect superexchange interactions.

Insights into Sorption-Mineralization Mechanism for Sustainable Granular Composite of MgO-CaO-Al2O3-SiO2-CO2 Based on Nanosized Adsorption Centers and Its Effect on Aqueous Cu(II) Removal.

Although copper is needed for living organisms at low concentrations, it is one of the pollutants that should be monitored along with other heavy metals. A novel and sustainable composite mineralizing sorbent based on MgO-CaO-Al2O3-SiO2-CO2 with nanosized adsorption centers was synthesized using natural calcium-magnesium carbonates and clay aluminosilicates for copper sorption. An organometallic modifier was added as a temporary binder and a source of inovalent ions participating in the reactions of defect formation and activated sintering. The sorbent-mineralizer samples of specified composition and properties showed irreversible sorption of Cu2+ ions by the ion exchange reactions Ca2+ ↔ Cu2+ and Mg2+ ↔ Cu2+. The topochemical reactions of the ion exchange 2OH- → CO32-, 2OH- → SO42- and CO32- → SO42- occurred at the surface with formation of the mixed calcium-copper carbonates and sulfates structurally connected with aluminosilicate matrix. The reverse migration of ions to the environment is blocked by the subsequent mineralization of the newly formed interconnected aluminosilicate and carbonate structures.

The influence of the synthesis conditions on the magnetic behaviour of the densely packed arrays of Ni nanowires in porous anodic alumina membranes.

The densely packed arrays of Ni nanowires of 70 nm diameter and 6-12 µm length were obtained via electrodeposition into porous alumina membranes (PAAMs) of 55-75 µm thickness. The morphology, microstructure and magnetic properties between the room and liquid-helium temperature of Ni nanowires in PAAMs have been investigated using scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry. The crystal structure of the Ni nanowires is fcc with (220) preferred orientation. The magnetic characteristics of the Ni nanowires in PAAMs were compared with the same characteristics of bulk Ni and with other researchers' data. The effect of the porous alumina membrane and the Ni nanowires synthesis conditions on the magnetic characteristics of Ni nanowire arrays has been studied. The coercivity reached more than 750 kOe and the squareness ratio up to 0.65 under the proposed optimal synthesis conditions for Ni nanowires. Magnetic parameters of the densely packed arrays of Ni nanowires allow using them in magnetic recording media, hard disk drives, storage systems and sensors. In addition, such structures are of considerable interest for basic research on nanomagnetism which is significantly different from the magnetic properties of bulk and thin films materials.

Impact of Tm3+ and Tb3+ Rare Earth Cations Substitution on the Structure and Magnetic Parameters of Co-Ni Nanospinel Ferrite.

Tm-Tb co-substituted Co-Ni nanospinel ferrites (NSFs) as (Co0.5Ni0.5) [TmxTbxFe2-2x]O4 (x = 0.00-0.05) NSFs were attained via the ultrasound irradiation technique. The phase identification and morphologies of the NSFs were explored using X-rays diffraction (XRD), selected area electron diffraction (SAED), and transmission and scanning electronic microscopes (TEM and SEM). The magnetization measurements against the applied magnetic field (M-H) were made at 300 and 10 K with a vibrating sample magnetometer (VSM). The various prepared nanoparticles revealed a ferrimagnetic character at both 300 and 10 K. The saturation magnetization (Ms), the remanence (Mr), and magneton number (nB) were found to decrease upon the Tb-Tm substitution effect. On the other hand, the coercivity (Hc) was found to diminish with increasing x up to 0.03 and then begins to increase with further rising Tb-Tm content. The Hc values are in the range of 346.7-441.7 Oe at 300 K to 4044.4-5378.7 Oe at 10 K. The variations in magnetic parameters were described based on redistribution of cations, crystallites and/or grains size, canting effects, surface spins effects, super-exchange interaction strength, etc. The observed magnetic results indicated that the synthesized (Co0.5Ni0.5)[TmxTbxFe2-x]O4 NSFs could be considered as promising candidates to be used for room temperature magnetic applications and magnetic recording media.

The Effect of Heat Treatment on the Microstructure and Mechanical Properties of 2D Nanostructured Au/NiFe System.

Nanostructured NiFe film was obtained on silicon with a thin gold sublayer via pulsed electrodeposition and annealed at a temperature from 100 to 400 °C in order to study the effect of heat treatment on the surface microstructure and mechanical properties. High-resolution atomic force microscopy made it possible to trace stepwise evolving microstructure under the influence of heat treatment. It was found that NiFe film grains undergo coalescence twice-at ~100 and ~300 °C-in the process of a gradual increase in grain size. The mechanical properties of the Au/NiFe nanostructured system have been investigated by nanoindentation at two various indentation depths, 10 and 50 nm. The results showed the opposite effect of heat treatment on the mechanical properties in the near-surface layer and in the material volume. Surface homogenization in combination with oxidation activation leads to abnormal strengthening and hardening-up of the near-surface layer. At the same time, a nonlinear decrease in hardness and Young's modulus with increasing temperature of heat treatment characterizes the internal volume of nanostructured NiFe. An explanation of this phenomenon was found in the complex effect of changing the ratio of grain volume/grain boundaries and increasing the concentration of thermally activated diffuse gold atoms from the sublayer to the NiFe film.

Thermal History Dependent Al Distribution in Aluminum Substituted Strontium Hexaferrite.

Single crystals of aluminum substituted strontium hexaferrite SrFe12-xAlxO19 were grown from sodium oxide based flux. The substitution level aimed for was x = 1.2. Annealing experiments performed on single crystals show that the Al distribution on the five iron sites of the hexaferrite structure depends on the annealing time at 900 °C. Single crystal X-ray diffractometry shows that annealing a crystal after the initial synthesis has an impact on the Al content on the octahedrally and tetrahedrally coordinated sites. Furthermore, it was found that heating in a corundum crucible increases the overall Al content. Magnetic measurements show that annealing in a platinum or corundum crucible decreases coercivity and remanence while the saturation magnetization is hardly influenced.

High Entropy Oxide Phases with Perovskite Structure.

The possibility of the formation of high entropy single-phase perovskites using solid-state sintering was investigated. The BaO-SrO-CaO-MgO-PbO-TiO2, BaO-SrO-CaO-MgO-PbO-Fe2O3 and Na2O-K2O-CaO-La2O3-Ce2O3-TiO2 oxide systems were investigated. The optimal synthesis temperature is found between 1150 and 1400 °C, at which the microcrystalline single phase with perovskite structure was produced. The morphology, chemical composition, crystal parameters and dielectric properties were studied and compared with that of pure BaTiO3. According to the EDX data, the single-phase product has a formula of Na0.30K0.07Ca0.24La0.18Ce0.21TiO3 and a cubic structure.

Electrochemical Behaviour of Ti/Al2O3/Ni Nanocomposite Material in Artificial Physiological Solution: Prospects for Biomedical Application.

Inorganic-based nanoelements such as nanoparticles (nanodots), nanopillars and nanowires, which have at least one dimension of 100 nm or less, have been extensively developed for biomedical applications. Furthermore, their properties can be varied by controlling such parameters as element shape, size, surface functionalization, and mutual interactions. In this study, Ni-alumina nanocomposite material was synthesized by the dc-Ni electrodeposition into a porous anodic alumina template (PAAT). The structural, morphological, and corrosion properties were studied using x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and electrochemical techniques (linear sweep voltammetry). Template technology was used to obtain Ni nanopillars (NiNPs) in the PAAT nanocomposite. Low corrosion current densities (order of 0.5 µA/cm2) were indicators of this nanocomposite adequate corrosion resistance in artificial physiological solution (0.9% NaCl). A porous anodic alumina template is barely exposed to corrosion and performs protective functions in the composite. The results may be useful for the development of new nanocomposite materials technologies for a variety of biomedical applications including catalysis and nanoelectrodes for sensing and fuel cells. They are also applicable for various therapeutic purposes including targeting, diagnosis, magnetic hyperthermia, and drug delivery. Therefore, it is an ambitious task to research the corrosion resistance of these magnetic nanostructures in simulated body fluid.

Extremely Polysubstituted Magnetic Material Based on Magnetoplumbite with a Hexagonal Structure: Synthesis, Structure, Properties, Prospects.

Crystalline high-entropy single-phase products with a magnetoplumbite structure with grains in the µm range were obtained using solid-state sintering. The synthesis temperature was up to 1400 °C. The morphology, chemical composition, crystal structure, magnetic, and electrodynamic properties were studied and compared with pure barium hexaferrite BaFe12O19 matrix. The polysubstituted high-entropy single-phase product contains five doping elements at a high concentration level. According to the EDX data, the new compound has a formula of Ba(Fe6Ga1.25In1.17Ti1.21Cr1.22Co1.15)O19. The calculated cell parameter values were a = 5.9253(5) Å, c = 23.5257(22) Å, and V = 715.32(9) ų. The increase in the unit cell for the substituted sample was expected due to the different ionic radius of Ti/In/Ga/Cr/Co compared with Fe3+. The electrodynamic measurements were performed. The dielectric and magnetic permeabilities were stable in the frequency range from 2 to 12 GHz. In this frequency range, the dielectric and magnetic losses were -0.2/0.2. Due to these electrodynamic parameters, this material can be used in the design of microwave strip devices.

Fe3O4 Nanoparticles for Complex Targeted Delivery and Boron Neutron Capture Therapy.

Magnetic Fe3O4 nanoparticles (NPs) and their surface modification with therapeutic substances are of great interest, especially drug delivery for cancer therapy, including boron-neutron capture therapy (BNCT). In this paper, we present the results of boron-rich compound (carborane borate) attachment to previously aminated by (3-aminopropyl)-trimethoxysilane (APTMS) iron oxide NPs. Fourier transform infrared spectroscopy with Attenuated total reflectance accessory (ATR-FTIR) and energy-dispersive X-ray analysis confirmed the change of the element content of NPs after modification and formation of new bonds between Fe3O4 NPs and the attached molecules. Transmission (TEM) and scanning electron microscopy (SEM) showed Fe3O4 NPs' average size of 18.9 nm. Phase parameters were studied by powder X-ray diffraction (XRD), and the magnetic behavior of Fe3O4 NPs was elucidated by Mössbauer spectroscopy. The colloidal and chemical stability of NPs was studied using simulated body fluid (phosphate buffer-PBS). Modified NPs have shown excellent stability in PBS (pH = 7.4), characterized by XRD, Mössbauer spectroscopy, and dynamic light scattering (DLS). Biocompatibility was evaluated in-vitro using cultured mouse embryonic fibroblasts (MEFs). The results show us an increasing of IC50 from 0.110 mg/mL for Fe3O4 NPs to 0.405 mg/mL for Fe3O4-Carborane NPs. The obtained data confirm the biocompatibility and stability of synthesized NPs and the potential to use them in BNCT.