To optimize the heating properties of magnetic nanoparticles (MNPs) in hyperthermia applications, it is necessary to calculate area their hysteresis loops an alternating field. The three types theories suitable for describing MNPs are presented and compared numerical simulations: equilibrium functions, Stoner-Wohlfarth model based (SWMBTs) linear response theory (LRT). Suitable formulas major cycles deduced from SWMBTs simulations; domain validity analytical formula explicitly studied. In...

Abstract Progress in the prediction and optimization of heating magnetic nanoparticles an alternating field is highly desirable for their application hyperthermia. Here, a model system consisting metallic iron with size ranging from 5.5 to 28 nm extensively studied. Their properties depend strongly on size: behaviors typical single‐domain particles superparamagnetic regime, ferromagnetic multi‐domain are observed. Ferromagnetic best candidates display highest specific losses reported...

When magnetic nanoparticles (MNPs) are single domain and magnetically independent, their properties the conditions to optimize efficiency in hyperthermia applications now well understood. However, influence of interactions on is still unclear. Here, we report high-frequency hysteresis loop measurements a model system consisting MNPs with same size but varying anisotropy, which an interesting way tune relative strength interactions. A clear correlation between MNP anisotropy squareness...

We report a tunable organometallic synthesis of monodisperse iron carbide and core/shell iron/iron nanoparticles displaying high magnetization good air-stability. This process based on the decomposition Fe(CO)5 Fe(0) seeds allows control amount carbon diffused therefore tuning magnetic anisotropy. results in unprecedented hyperthermia properties at moderate fields, range medical treatments.

Abstract The use of magnetic nanoparticles to convert electromagnetic energy into heat is known be a key strategy for numerous biomedical applications but also an approach growing interest in the field catalysis. heating efficiency limited by poor properties most them. Here we show that new generation iron carbide controlled size and with over 80 % crystalline Fe 2.2 C leads exceptional properties, which are much better than currently available nanoparticles. Associated catalytic metals (Ni,...

Whereas efficient and sensitive nanoheaters nanothermometers are demanding tools in modern bio- nanomedicine, joining both features a single nanoparticle still remains real challenge, despite the recent progress achieved, most of it within last year. Here we demonstrate successful realization this challenge. The heating is magnetically induced, temperature readout optical, ratiometric thermometric probes dual-emissive Eu3+/Tb3+ lanthanide complexes. low thermometer heat capacitance...

The nanoscale manipulation and charge transport properties of the [Fe(Htrz)2(trz)](BF4) spin-crossover compound is demonstrated. Such 1D nanostructures are attractive building blocks for nanoelectronic switching memory devices.

Addition of Co2(Co)9 and Ru3(CO)12 on preformed monodisperse iron(0) nanoparticles (Fe(0) NPs) at 150 °C under H2 leads to core–shell Fe@FeCo NPs a thin discontinuous Ru(0) layer supported the initial Fe(0) NPs. The new complex were studied by state-of-the-art transmission electron microscopy techniques as well X-ray diffraction, Mössbauer spectroscopy, magnetic measurements. These particles display large heating powers (SAR) when placed in an alternating field. combination surface catalytic...

We report on hyperthermia measurements a colloidal solution of 14.2±1.5 nm monodisperse FeCo nanoparticles (NPs). Losses as function the magnetic field display sharp increase followed by plateau, which is what expected for losses ferromagnetic single-domain NPs. The frequency dependence coercive deduced from measurement and in quantitative agreement with simple model noninteracting measured (1.5 mJ/g) compare to highest literature, although saturation magnetization NPs well below bulk one.

Iron oxide nanoparticles have found an increasing number of biomedical applications as sensing or trapping platforms and therapeutic and/or diagnostic agents. Most these are based on their magnetic properties, which may vary depending the nanoparticle aggregation state concentration. In this work, we assess effect inter- intra-aggregate dipolar interactions heat dissipation power AC hysteresis loops upon concentration hydrodynamic aggregate size. We observe different effects produced by...

The influence of a transverse static magnetic field on the hyperthermia properties is studied system large-losses ferromagnetic FeCo nanoparticles. simultaneous measurement high-frequency hysteresis loops and temperature rise provides an interesting insight into losses heating mechanisms. A only 40 mT enough to cancel nanoparticles, result reproduced using numerical simulations loops. These results cast doubt possibility perform someday inside resonance imaging setup.

Understanding the influence of dipolar interactions in magnetic hyperthermia (MH) experiments is crucial importance for a fine optimization nanoparticle (NP) heating power. In this study, we use kinetic Monte-Carlo algorithm to calculate hysteresis loops, so both time and temperature are correctly taken into account. It demonstrated that reproduces high-frequency loop superparamagnetic NPs ferromagnetic ones without any ad-hoc parameters. The easily parallelizable calculation on several...

Using the electrochemical route, cobalt ferrite nanoparticles (NPs) with two different sizes were synthesized and stabilized in water by coating citric acid. The specific absorption rate (SAR) values of aqueous suspensions magnetic crystal 13 28 nm investigated frequency range 32–101 kHz up to 51 mT. SAR higher for larger NPs reached 133 W/g. Numerical simulations are used a quantitative analysis hyperthermia experiments seem indicate that multidomain. Cytotoxicity was also performed HeLa...

Ferromagnetic nanomaterials exhibit unique magnetic properties common to materials with dimensions approaching the atomic scale and have potential applications in data storage. Technological applications, however, require that detailed behaviors configurations of individual interacting nano-objects be clarified. We determined remnant single crystalline 30 nm Fe nanocubes groups using off-axis electron holography a transmission microscope. Our measurements on an isolated cube reveal vortex...

Nanotherapy using targeted magnetic nanoparticles grafted with peptidic ligands of receptors overexpressed in cancers is a promising therapeutic strategy. However, nanoconjugation peptides can dramatically affect their properties respect to receptor recognition, mechanism internalization, intracellular trafficking, and fate. Furthermore, investigations are needed better understand the whereby application an alternating field cells containing induces cell death. Here, we designed nanoplatform...

A setup for measuring the high-frequency hysteresis loops of magnetic samples is described. An alternating field in range 6–100 kHz with amplitude up to 80 mT produced by a Litz wire coil. The latter air-cooled using forced-air approach so no water flow required run setup. High-frequency are measured system pick-up coils and numerical integration signals. Reproducible measurements obtained frequency 6–56 kHz. Measurement examples on ferrite cylinders iron oxide nanoparticle ferrofluids...

Magnetic heating by nanoparticles has recently been successfully employed in heterogeneous catalysis. In such processes, the maximum temperature that can be reached depends on Curie (Tc) of material. Here, order to extend range accessible temperatures and consequently possible reactions, those requiring high temperatures, we developed fully characterized a series FeCo containing different concentrations cobalt, tune their magnetic properties Tc. Their efficiency is compared iron carbide...

The destruction of cells using the mechanical activation magnetic nanoparticles with low-frequency fields constitutes a recent and interesting approach in cancer therapy. Here, we showed that superparamagnetic iron oxide as small 6 nm were able to induce death pancreatic cancer-associated fibroblasts, chosen model. An exhaustive screening amplitude, frequency, type (alternating

The influence that dipole-dipole interactions exert on the dynamics of magnetization nanometer-sized Co clusters has been studied by means ac and dc susceptibility experiments. These grow in a quasiordered layered structure, where all relevant parameters can be tailored measured independently. Our data show without ambiguity magnetic relaxation becomes slower as degree interaction increases. effective activation energy increases linearly with number nearest neighbor clusters, evolving from...

We report on the observation of magnetoresistance in a Sr2FeMoO6 (SFMO)-based tunnel junction. This result is obtained by combining three-step process for growth layer pulsed laser deposition with technology allowing definition nanometer-sized junctions. A clear positive magnetoresistive signal 50% at low temperature Sr2FeMoO6/SrTiO3/Co Since SrTiO3/Co interface known to have negative spin polarization about 20%, this yields SFMO, which we find amount more than 85% our film. confirms...

In this work, a straightforward aqueous synthesis for mass production (up to 20 g) of uniform and crystalline magnetite nanoparticles with core sizes between 30 nm, which are the optimum nanoparticle hyperthermia applications, is proposed. Magnetic heating properties have been analyzed showing very high saturation magnetization magnetic values. To stabilize naked nanocrystals at physiological pH increase their circulation time in blood, they covalently coated carboxymethyl dextran,...