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To realize magnetic hyperthermia as an alternate stand-alone therapeutic procedure for cancer treatment, magnetic nanoparticles with optimal performance, within the biologically safe limits, are to be produced using simple, reproducible and scalable techniques. Herein, we present a simple, one-step approach for synthesis of water-dispersible magnetic nanoclusters (MNCs) of superparamagnetic iron oxide by reducing of Fe 2 (SO 4 ) 3 in sodium acetate (alkali), poly ethylene glycol (capping ligand), and ethylene glycol (solvent and reductant) in a microwave reactor. The average size and saturation magnetization of the MNC’s are tuned from 27 to 52 nm and 32 to 58 emu/g by increasing the reaction time from 10 to 600 s. Transmission electron microscopy images reveal that each MNC composed of large number of primary Fe 3 O 4 nanoparticles. The synthesised MNCs show excellent colloidal stability in aqueous phase due to the adsorbed PEG layer. The highest SAR value of 215 ± 10 W/g Fe observed in 52 nm size MNC at a frequency of 126 kHz and field of 63 kA/m suggest the potential use of these MNC in hyperthermia applications. This study further opens up the possibilities to develop metal ion-doped MNCs with tunable sizes suitable for various biomedical applications using microwave assisted synthesis. [ABSTRACT FROM AUTHOR]

• Size effect of iron oxide NPs (NP10, NP20, NP30, and NP40) was investigated in pumpkin. • TEM and VSM analyses revealed root-to-shoot translocation of all tested NPs. • NP30 exhibits the highest translocation performance, while a negligible amount of NP10 and NP40 reached to the leaves. • The status of nutrient elements significantly altered depend on NP-type. • The findings could be important for selecting the most suitable NP size for agricultural practices. The ability of nanoparticles (NPs) to migrate in the plant body is an important issue to ensure that the NPs reach the desired tissue and to be able to select the most efficient NPs for agricultural applications. In this study, the size impact of four different iron oxide NPs (8–10, 18–20, 20–40, and 30–50 nm referred as NP10, NP20, NP30, and NP40, respectively) on their translocation in pumpkin was elucidated. To assess the root-to-shoot translocation, phloem sap was examined under transmission electron microscope (TEM). In addition, vibrating sample magnetometer (VSM) and inductively coupled plasma optical emission spectrophotometry (ICP-OES) analyses of stem and leaf tissues were performed to confirm size-dependent translocation. TEM and VSM analyses verified root-to-stem translocation of all tested NPs. The NPs treatment significantly altered the abundances of Mn, Cu, K, P, Al, Mg, and Na in tissues. The iron (Fe) content was abundant in plants treated with NP30 and NP20, and the lowest in plants treated with NP10 and NP40. Together with, only NP30 was found to be significantly translocated to the leaves, where it was 393 mg/kg in DW, about 2.3 times that of control. These findings pointed out the size-dependent translocation of NPs. It seems that biological barriers in the vascular bundle appear to restrict the migration, especially for NPs with an average size of 40 nm and above in pumpkins. These findings are important for selecting the most suitable size of iron oxide NPs for use in agricultural practices. [ABSTRACT FROM AUTHOR]

The low cost and high output methods of high-power physical dispersion: the electrical explosion of wire and the laser target evaporation were elaborated for the production of iron oxide magnetic nanoparticles (MNPs) with controlled dispersion parameters and highly reproducible functional properties. The synthesized MNPs were spherical in shape with mean diameter 10 nm and lognormal particle size distribution. The phase composition, shape, particle size and functional properties of MNPs were cross-examined by a variety of contemporary experimental techniques. The phase structure of MNPs corresponds to the inverse spinel of magnetite. Meanwhile, due to the non-equilibrium conditions of the dispersion chemical composition of MNPs is close to maghemite—γ-Fe 2 O 3 . Their magnetic properties are reproducible and very close to the single domain superparamagnetic behavior. The stability of the suspensions of these MNPs and their applicability in the biophysical purposes such as magneto-induced heating have been demonstrated. [ABSTRACT FROM AUTHOR]

Abstract: Thermal decomposition of the trinuclear complex [Fe2CrO(CH3COO)6(H2O)3]NO3 at 300, 400 and 500°C gave γ-Fe2O3 nanoparticles along with amorphous chromium oxide, while decomposition of the same starting compound at 600 and 700°C led to the formation of α-(Fe2/3Cr1/3)2O3 nanoparticles. Size of γ-Fe2O3 nanoparticles, determined by X-ray diffraction, was in the range from 9 to 11nm and increased with formation temperature growth. Average size of α-(Fe2/3Cr1/3)2O3 nanoparticles was about 40nm and almost did not depend on the temperature of its formation. γ-Fe2O3 nanoparticles possessed superparamagnetic behavior with blocking temperature 180–250K, saturation magnetization 29–35emu/g at 5K, 44–49emu/g at 300K and coercivity 400–600Oe at 5K. α-(Fe2/3Cr1/3)2O3 nanoparticles were characterized by low magnetization values (2.7emu/g at 70kOe). Such magnetic properties can be caused by non-compensated spins and defects present on the surface of these nanoparticles. The increase of α-(Fe2/3Cr1/3)2O3 formation temperature led to decrease of magnetization (being compared for the same fields), which may be caused by decrease of the quantity of defects or non-compensated spins (due to decrease of particles'' surface). [Copyright &y& Elsevier]

Abstract: Radio-frequency heated magnetic nanoaparticle suspensions have potential applications in cancer hyperthermia. To optimize these systems for hyperthermia applications it is important to be able to predict how their heat generation or specific absorption rate (SAR) is influenced by various factors, including nanoparticle coating or functionalization and aggregation. However, at present it is unclear how well-existing models predict experimental SAR results. Direct comparisons between predicted and measured SAR are scarce, despite an abundance of works reporting on heat generation rate of various magnetic nanoparticles suspensions. The main objective of this paper is to experimentally assess the validity of current models for SAR and extract information on the effects of coating and aggregation on heat generation rate. In this context, AC susceptibility and magnetization of suspensions of uncoated particles, as well as particles with aminosilane and carboxymethyl-dextran functionalizations, were measured. These properties were then used to predict the heat generation rate in alternating magnetic field starting from first principles, which was then compared to measured SAR. It was found that experimental SAR agrees relatively well with predictions (by a factor of two) when using experimental susceptibility values for the SAR calculation. However, for uncoated and amine-functionalized particles poor agreement (more than an order of magnitude difference) was found when the experimental susceptibility was substituted with predictions based on the Debye model. This apparent discrepancy is attributed to dipolar interactions between nanoparticles within aggregates in these samples, which enhances the imaginary part of the susceptibility and, consequently, the SAR values. The results also suggest that the thermal resistance effect of the coating has little influence on the SAR. [Copyright &y& Elsevier]

Abstract: Magnetic iron oxide nanoparticles are promising tools for medical applications like hyperthermia or magnetic drug targeting. The relevant properties in these applications strongly depend on particle size and size distribution. In order to investigate the influence of mean size as well as size distribution, iron oxide powders from particles by a cyclic method based on “conventional” precipitation from Fe-salt solution were prepared. Increasing mean particle size with increasing number of cycles is confirmed by XRD. Magnetic parameters of the saturation hysteresis loop, hysteresis losses calculated from minor loops and switching field distributions are shown. A fractionation experiment on a fluid sample of particles prepared by 3 cycles was carried out in order to improve the hysteresis losses. [Copyright &y& Elsevier]

Abstract: We demonstrate a single-step facile approach for the fabrication of citric acid functionalized (citrate-stabilized) Fe3O4 aqueous colloidal magnetic nanoparticles (CA-MNP) of size 8–10nm using soft chemical route. The surface functionalization of Fe3O4 nanoparticles with citric acid was evident from infrared spectroscopy, thermal and elemental analyses, and zeta-potential measurements. The drug-loading efficiency of CA-MNP was investigated using doxorubicin hydrochloride (DOX) as a model drug to evaluate their potential as a carrier system. The quenching of fluorescence intensity and decrease in surface charge of drug loaded CA-MNP strongly suggest the interaction/attachment of drug molecules with CA-MNP. More specifically, the present investigation discusses a method for entrapping positively charged drugs onto the surface of negatively charged CA-MNP through electrostatic interactions and suggests that bound drug molecules will be released in appreciable amounts in the mild acidic environments of the tumors. Furthermore, the aqueous colloidal stability, optimal magnetization, good specific absorption rate (under external AC magnetic field) and cytocompatibility with cells suggested that CA-MNP is appropriate candidate for biomedical applications. [ABSTRACT FROM AUTHOR]

Abstract: Citric acid coated magnetite nanoparticles were synthesized using a one-step and two-step co-precipitation method at different temperatures. The stability of the nanoparticles in aqueous media was compared. The magnetic heating characteristics in an alternating magnetic field were examined and specific absorption rates were determined. The nanoparticles were characterized by various techniques (Fourier transform infrared, UV spectrophotometry, thermogravimetric analysis, dynamic light scattering, transmission electron microscopy, X-ray diffraction and vibrating sample magnetometry). The temperature of synthesis and mode of functionalizing the particles affected their physical and magnetic properties. Higher temperatures led to increased specific absorption rates for both methods but more stable hydrophilic superparamagnetic nanoparticles were obtained in the one-step method. [Copyright &y& Elsevier]

Abstract: A magnetic field of 12T was applied during the annealing of amorphous α-Fe2O3 microspheres. The authors demonstrate that magnetic field processing leads to the formation of γ-Fe2O3 phases in the microspheres, and the field-treated microspheres exhibit typical room-temperature ferromagnetic behavior, whereas non-field-heated sample presents paramagnetism. The improvement in magnetic properties is considered to be a result of magnetic field-induced transformation from α-Fe2O3 to γ-Fe2O3. [Copyright &y& Elsevier]

Abstract: In this study, a new method is proposed for the preparation of Fe3O4 from iron oxyhydroxides (goethite, akaganeite, lepidocrocite, feroxyhyte and ferrihydrite) or iron oxide (hematite) and ferrous salt in aqueous solution. The product is magnetite with various particle sizes. Products are characterized by X-ray powder diffraction, IR spectra and vibrating sample magnetometery. [Copyright &y& Elsevier]

Abstract: We demonstrate a single-step facile approach for highly water-stable assembly of amine-functionalized Fe3O4 nanoparticles using thermal decomposition of Fe-chloride precursors in ethylene glycol medium in the presence of ethylenediamine. The average size of nanoassemblies is 40±1nm, wherein the individual nanoparticles are about 6nm. Amine-functionalized properties are evident from Fourier transform infrared spectrometer (FTIR), thermal and elemental analyses. The saturation magnetization and spin-echo r 2 of the nanoassemblies were measured to be 64.3emu/g and 314.6mM−1 s−1, respectively. The higher value of relaxivity ratio (r 2/r 1=143) indicates that nanoassemblies are a promising high-efficiency T2 contrast agent platform. [Copyright &y& Elsevier]

Abstract: Superparamagnetic nanoparticles have been widely applied in various bio-medical applications. To date, it is still a challenge to synthesize nanosized Fe3O4 particles with controlled size and distribution. In this paper, a novel solvent-free thermal decomposition method is reported for synthesizing Fe3O4 nanoparticles. Size and morphology of the nanoparticles are determined by TEM while the structure of the nanoparticles is identified by FTIR, XPS and TGA measurements. Magnetic properties of the obtained particles are determined using VSM and SQUID measurement. The particle size of the Fe3O4 can be tailored by adjusting either reaction temperature or time. When the reaction temperature is increased to 330°C and the reaction time is extended to 4h, the average particle size of the obtained nanoparticles is ∼9nm, while Ms value reaches ∼76emu/g. The as synthesized Fe3O4 nanoparticles show well-established superparamagnetic properties with the blocking temperature at around 100K. [Copyright &y& Elsevier]

Abstract: The aim of this research is to elucidate the size effect of magnetic nanoparticles on the resultant magneto-dielectric properties of polymer nanocomposites at radio frequencies. The block copolymer of [styrene-b-ethylene/butylene-b-styrene] (SEBS) was utilized as a matrix for the templating of magnetic nanoparticles. Surfactant-modified iron oxide () nanoparticles of various sizes were successfully synthesized by a seed-mediated growth method. The surfactant prevented aggregation and provided compatibility with the polymer matrix. The nucleation and growth of nanoparticles was controlled by changing the concentration ratio of surfactant to iron-precursor. The free iron ions present during synthesis are the major factor contributing to the growth of larger particles. The nanoparticle critical size for superparamagnetic to ferrimagnetic transition was determined to be near 30nm at room temperature. The dielectric permittivity of the polymer composite increased with increasing amount of doping, and was not influenced by nanoparticle size. However, the magnetic permeability () of the composites was significantly influenced by the size of nanoparticles templated within the block copolymer matrix due to thermal energy fluctuations from the nanoparticle surroundings. [Copyright &y& Elsevier]

Abstract: Iron oxide nanoparticles of diameter 14nm were synthesized by applying Pt seed-assisted heterogeneous thermal decomposition of Fe(CO)5 in a two-stage procedure. The intense heating treatment resulted in a remarkable mean volume increment compared to previous studies. This method is able to control the nanoparticle mean diameter, keeping the demand for thermal energy at low levels. High-resolution electron microscopy images and the corresponding electron diffraction patterns revealed the appearance of a FePt3 core in each nanoparticle, surrounded by highly crystallized inverse spinel Fe3O4 formed after atmospheric oxidation, as shown by a combination of X-ray diffraction and chemical analysis. Magnetic measurements indicated that the presence of Pt-rich core does not cause any visible modification to the values of saturation magnetization and anisotropy constant of nanoparticles, compared to homogeneously nucleated iron oxide particles of the same size. [Copyright &y& Elsevier]

Abstract: Magnetic iron oxide nanoparticles/C and α-Fe/iron oxide nanoparticles/C composites were synthesized through the formation of polymer gel with highly dispersed magnetic iron oxide nanoparticles in hydrothermal system, followed by carbonizing the gel at 400 and 1000°C under N2 atmosphere, respectively. The phase component, structure and magnetic properties of these magnetic composites were characterized by X-ray diffraction analysis, transmission electron microscopy and magnetic measurements. Spherical iron oxide nanoparticles with variable average diameter (12.5–25nm) and narrow size distribution were homogeneously embedded in amorphous carbon matrix when the gel was annealed at 400°C. Increasing the annealing temperature to higher temperature (1000°C) could result in the partial reduction of iron oxide to α-Fe through nanoscale carbothermic reaction and the graphitization of amorphous carbon matrix as well as the change of superparamagnetism into ferromagnetism. The magnetic properties of iron oxide and α-Fe/iron oxide nanoparticles make the as-obtained composites useful for various magnetic applications. [Copyright &y& Elsevier]

Abstract: Superparamagnetic iron oxide nanoparticles (SPIONs) were coated with polyethylenimine. Here, we briefly describe the synthesis as well as DNA:PEI:SPION complexes and the characterization of the compounds according to their particle size, ζ-potential, morphology, DNA complexing ability, magnetic sedimentation, and colloidal stability. PEI coating of SPIONs led to colloidally stable beads even in high salt concentrations over a wide pH range. DNA plasmids and PCR products encoding for green fluorescent protein were associated with the described beads. The complexes were added to cells and exposed to permanent and pulsating magnetic fields. Presence of these magnetic fields significantly increased the transfection efficiency. [Copyright &y& Elsevier]

Abstract: Water-soluble double-coated magnetic nanoparticles (NPs) containing cytotoxic decyldimethyl(-dimethylaminoethoxy)silane methiodide (AA) molecule sorbed at biocompatible magnetic particles, which consist of magnetite pre-coated with oleic acid (OA), have been prepared. X-ray line profile broadening analysis was used for crystallite size determination. The method of magnetogranulometry has been used for determination of diameter of iron oxide magnetic core and magnetic properties of NPs prepared. In vitro cytotoxicity on monolayer tumor cell lines HT-1080 (human fibrosarcoma), MG-22A (mouse hepatoma) and normal mouse fibroblasts (NIH 3T3) has been studied. It was revealed that all the water-based colloidal solutions obtained are non-toxic and possess high NO-induction ability. [Copyright &y& Elsevier]

Abstract: Magnetic iron oxide nanopowders were produced with the laser evaporation technique under normal process gas pressure. In addition, the generated particles were coated in situ with stearic acid and separated on magnets. The methods and the used laboratory setup are briefly described. Influences of essential process conditions, particularly the use of continuous and pulsed laser radiation as well as the properties of the process gas, were experimentally investigated. The produced nanopowders were analysed with TEM, XRD, and magnetic measurements and confirmed the in-principle suitability of the presented method. [Copyright &y& Elsevier]

Abstract: Iron oxide nanoparticles made from the thermal decomposition method are highly uniform in all respects (size, shape, composition and crystallography), making them ideal candidates for many bioapplications. The surfactant coating on the as-synthesized nanoparticles renders the nanoparticles insoluble in aqueous solutions. For biological applications nanoparticles must be water soluble. Here we demonstrate the phase transfer of our nanoparticles with the biocompatible copolymer Pluronic F127. Transmission electron microscopy, Fourier transform infrared spectroscopy and dynamic light scattering indicate that the nanoparticles are coated discretely. Magnetic measurements show that the nanoparticles remain superparamagnetic with saturation magnetization ∼96% of the maximum theoretical value. [Copyright &y& Elsevier]

Abstract: The detection of superparamagnetic iron oxide nanoparticles (SPION) in synoviocytes is reported. Synoviocytes were incubated for 2, 12, 24 and 48h with 1.5mg/ml of PVA coated SPION under the influence of magnets (12h). Particles were well tolerated by the synoviocytes, were easily detected using the Turnbulls and Prussian blue reactions between 12 and 24h. [Copyright &y& Elsevier]

Abstract: Novel superparamagnetic iron oxide nanoparticles coated with polymerized PEGylated bilayers were prepared. Bilayers composed of 10-undecenoic acid (UD) inner and UDPEG (PEG ester of UD) outer layers are resistant to aggregation after -irradiation. Various methods of coating were developed to prepare small (60–100nm) and ultrasmall (20–35nm) particles without size separation processes. [Copyright &y& Elsevier]

Abstract: In this paper, the authors present their results regarding the cellular division rate and the percentage of chromosomal aberrations in the root meristematic cells of agricultural plants when cultivated in the presence of different concentrations of aqueous ferrofluid, ranging between 10 and 250μL/L. The agricultural species (Zea mays) with a major role in the life of people was chosen for the experimental project. The water-based ferrofluid was prepared following the chemical co-precipitation method, using tetramethylammonium hydroxide as magnetite core stabilizer. Microscopic investigations (cytogenetic tests) resulted in the evaluation of the mitotic and chromosomal aberration index. They appeared to increase following ferrofluid addition. [Copyright &y& Elsevier]