Efficiency Of Iron Oxide Nanoparticles Research Articles

Carbothermal treated iron oxide nanoparticles with improving magnetic heating efficiency for hyperthermia

Iron oxide nanoparticles with high magnetic heating efficiency is highly desired for magnetic hyperthermia applications. In this paper, carbothermal treatments with graphene are used for improving the magnetic heating efficiency of iron oxide nanoparticles. With the increasing treatment temperature from 400 °C to 700 °C, the specific absorption rate (SAR) increases 2–7 folds. Oxygen vacancies resulted from carbon reduction process, along with the rapid grain growth (from 5.1 nm to 225.6 nm), improve eddy current loss. SAR calculations suggest that eddy current loss accounts up to 23.9%-78.5% of the total SAR after carbothermal treatments, which is the main factor for SAR improvements. This work may provide a methodological reference of preparing iron oxide nanoparticles for magnetic hyperthermia.

Carbothermal Treated Iron Oxide Nanoparticles with Improving Magnetic Heating Efficiency for Hyperthermia

Iron oxide nanoparticles with high magnetic heating efficiency is highly desired for magnetic hyperthermia applications. In this paper, carbothermal treatments with graphene were used for improving the magnetic heating efficiency of iron oxide nanoparticles. With the increasing treatment temperature from 400°C to 700°C, the specific absorption rate (SAR) increased 2-7 folds. Oxygen vacancies resulted from carbon reduction process, along with the rapid grain growth (from 5.1 nm to 225.6 nm), improved eddy current loss. SAR calculations suggested that eddy current loss accounted up to 23.9%-78.5% of the total SAR after carbothermal treatments, which was the main factor for SAR improvements. This work may provide a methodological reference of preparing iron oxide nanoparticles for magnetic hyperthermia.

Influence of biochar amendment and foliar application of iron oxide nanoparticles on growth, photosynthesis, and cadmium accumulation in rice biomass

The majority studies used the biochar or nanoparticles alone in metal-contaminated soils while less is known about the combined use of these amendments in metal-contaminated soils. We aimed to explore the efficiency of iron oxide nanoparticles (Fe NPs) and biochar on cadmium (Cd) uptake in rice in pot trial. An experiment was performed under ambient environmental conditions in a Cd-contaminated soil with and without biochar addition (1.0% w/w), and different Fe NP concentrations (0, 10, 20, 30 mg/L) were foliar sprayed at different time intervals (at 3rd, 4th, and 5th weeks of nursery transplantation in the pots) during the plant growth. After harvesting, rice growth, photosynthesis, Cd and Fe contents in rice tissues, and soil bioavailable Cd and soil pH were measured. Iron NPs enhanced the dry weights of rice tissues, chlorophyll concentrations, and gas exchange characteristics and the impact of NPs was further increased when the biochar was applied along with NPs. Iron NPs significantly decreased the intake of Cd in rice shoots by 31 and 42% and in rice roots by 26 and 39% with the foliar spray of Fe NPs (30 mg/L) without and with biochar, respectively. Foliar spray of Fe NPs reduced the total Cd accumulation by shoots, whereas the total Cd accumulation in the roots increased. The co-presence of Fe NPs and Cd enhanced the Fe concentrations in shoots of rice by 52 and 33% and in roots of rice by 32 and 21% when 30 mg/L Fe NPs were supplied with and without biochar, respectively. The effects of Fe NPs were higher with biochar application than without biochar except Fe concentrations in rice seedlings where the opposite trend was observed. The increase in biomass, Fe concentrations in tissues, and decrease in Cd levels in plants clearly demonstrate that Fe NPs + biochar could be a promising technique for the utilization of Cd-contaminated soils in the future.

Iron Oxide Nanoparticles in Photothermal Therapy.

Photothermal therapy is a kind of therapy based on increasing the temperature of tumoral cells above 42 °C. To this aim, cells must be illuminated with a laser, and the energy of the radiation is transformed in heat. Usually, the employed radiation belongs to the near-infrared radiation range. At this range, the absorption and scattering of the radiation by the body is minimal. Thus, tissues are almost transparent. To improve the efficacy and selectivity of the energy-to-heat transduction, a light-absorbing material, the photothermal agent, must be introduced into the tumor. At present, a vast array of compounds are available as photothermal agents. Among the substances used as photothermal agents, gold-based compounds are one of the most employed. However, the undefined toxicity of this metal hinders their clinical investigations in the long run. Magnetic nanoparticles are a good alternative for use as a photothermal agent in the treatment of tumors. Such nanoparticles, especially those formed by iron oxides, can be used in combination with other substances or used themselves as photothermal agents. The combination of magnetic nanoparticles with other photothermal agents adds more capabilities to the therapeutic system: the nanoparticles can be directed magnetically to the site of interest (the tumor) and their distribution in tumors and other organs can be imaged. When used alone, magnetic nanoparticles present, in theory, an important limitation: their molar absorption coefficient in the near infrared region is low. The controlled clustering of the nanoparticles can solve this drawback. In such conditions, the absorption of the indicated radiation is higher and the conversion of energy in heat is more efficient than in individual nanoparticles. On the other hand, it can be designed as a therapeutic system, in which the heat generated by magnetic nanoparticles after irradiation with infrared light can release a drug attached to the nanoparticles in a controlled manner. This form of targeted drug delivery seems to be a promising tool of chemo-phototherapy. Finally, the heating efficiency of iron oxide nanoparticles can be increased if the infrared radiation is combined with an alternating magnetic field.

Compositional Tuning of Light-to-Heat Conversion Efficiency and of Optical Properties of Superparamagnetic Iron Oxide Nanoparticles

Superparamagnetic iron oxide nanoparticles have played a fundamental role in the recent development of nanomedicine as one of the most popular imaging and therapeutic agents. Recently, the ability of iron magnetic nanoparticles for efficient heat generation under infrared optical excitation has even boosted the interest of the scientific community in this family of nanomaterials. The combination of magnetic and optical heating into a single nanostructure makes possible the development of advanced therapy treatments based on synergetic effects between these two heat sources that, in addition, could be combined with high penetration magnetic imaging. Despite its potential, the application of iron oxide nanoparticles in photothermal treatments is limited because the lack of knowledge about the physical mechanisms behind their light-to-heat conversion capacity. In this work, we have systematically investigated the photothermal efficiency of iron oxide nanoparticles with a variable composition achieved by part...

Improving the Heating Efficiency of Iron Oxide Nanoparticles by Tuning Their Shape and Size

Magnetic nanoparticle-mediated hyperthermia is a very promising therapy for cancer treatment. In this field, superparamagnetic iron oxide nanoparticles have been commonly employed because of their intrinsic biocompatibility, but they present some limitations that restrict their heating efficiency (specific absorption rate, SAR). Therefore, we have investigated how tuning the size and shape of these iron oxide nanoparticles can be useful to enhance their hyperthermia responses. Monodisperse and crystalline iron oxide nanoparticles have been synthesized by thermal decomposition in two different shapes (spheres and cubes) in a wide range of sizes, ∼10–100 nm. We have thoroughly characterized them both structurally (X-ray diffraction and transmission electron microscopy) and magnetically (physical property measurement system), and then we have analyzed their heating efficiency using a combination of calorimetric and AC magnetometry measurements (0–800 Oe, 300 kHz). We have been able to delimit a range of opti...

Photocatalytic efficiency of iron oxide nanoparticles for the degradation of priority pollutant anthracene

The present work demonstrates an efficient and cost effective methodology for the synthesis of iron oxide nanoparticles without the assistance of any capping agent. Two different forms of iron oxide nanoparticles, namely, goethite (α-FeOOH) and magnetite (Fe3O4) were synthesized and characterized through X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The XRD spectra were found concordant with JCPDS-ICDD data. The crystallite sizes for goethite and magnetite were found to be 9.85 and 14.13 nm, respectively. The mean particle sizes estimated via SEM analysis were 32.23 and 63.27 nm, respectively. Energy-dispersive X-ray (EDX) spectroscopy was used to estimate the elemental composition of the synthesized nanoparticles (NPs). The NPs were further used for the degradation of anthracene in the presence of UV light. The decay profiles of anthracene,a polycyclic aromatic hydrocarbon listed as a priority pollutant by United States Environmental Protection Agency (USEPA), were investigated with different forms of iron oxides NPs under UV irradiation at ambient temperature. Both forms of iron oxides were efficient for the photodegradation of anthracene. The decay profiles in both the cases followed the first-order kinetics. The half-lives for anthracene degradation were 3.21 and 4.39 h with α-FeOOH and Fe3O4, respectively. The results reveal that the photocatalytic activity of magnetite is low as compared to goethite.

Effects of inter- and intra-aggregate magnetic dipolar interactions on the magnetic heating efficiency of iron oxide nanoparticles.

Iron oxide nanoparticles have found an increasing number of biomedical applications as sensing or trapping platforms and therapeutic and/or diagnostic agents. Most of these applications are based on their magnetic properties, which may vary depending on the nanoparticle aggregation state and/or concentration. In this work, we assess the effect of the inter- and intra-aggregate magnetic dipolar interactions on the heat dissipation power and AC hysteresis loops upon increasing the nanoparticle concentration and the hydrodynamic aggregate size. We observe different effects produced by inter- (long distance) and intra-aggregate (short distance) interactions, resulting in magnetizing and demagnetizing effects, respectively. Consequently, the heat dissipation power under alternating magnetic fields strongly reflects such different interacting phenomena. The intra-aggregate interaction results were successfully modeled by numerical simulations. A better understanding of magnetic dipolar interactions is mandatory for achieving a reliable magnetic hyperthermia response when nanoparticles are located into biological matrices.

Uptake and clearance analysis of Technetium99m labelled iron oxide nanoparticles in a rabbit brain.

Nanoparticles as solid colloidal particles are extensively studied and used as anticancer drug delivery agents because of their physical properties. This current research aims to prepare water base suspension of uncoated iron oxide nanoparticles and their biodistribution study to different organs, especially the brain, by using a single photon emission computed tomography gamma camera. The water-based suspension of iron oxide nanoparticles was synthesised by a reformed version of the co-precipitation method and labelled with Tc99m for intravenous injection. The nanoparticles were injected without surface modification. X-ray diffraction (XRD), energy dispersive spectrometry (EDS) and transmission electron microscope (TEM) techniques were used for characterisation. Peaks of XRD and EDS indicate that the particles are magnetite and exist in aqueous suspension. The average diameter of iron oxide nanoparticles without any surface coating determined by TEM is 10 nm. These particles are capable of evading the reticuloendothelial system and can cross the blood-brain barrier in the rabbit. The labelling efficiency of iron oxide nanoparticles labelled with Tc99m is 85%, which is good for the biodistribution study. The sufficient amount of iron oxide nanoparticles concentration in the brain as compared with the surrounding soft tissues and their long blood retention time indicates that the water-based suspension of iron oxide nanoparticles may be an option for drug delivery into the brain.

Impact of magnetic field parameters and iron oxide nanoparticle properties on heat generation for use in magnetic hyperthermia

Heating of nanoparticles (NPs) using an AC magnetic field depends on several factors, and optimization of these parameters can improve the efficiency of heat generation for effective cancer therapy while administering a low NP treatment dose. This study investigated magnetic field strength and frequency, NP size, NP concentration, and solution viscosity as important parameters that impact the heating efficiency of iron oxide NPs with magnetite (Fe3O4) and maghemite (γ-Fe2O3) crystal structures. Heating efficiencies were determined for each experimental setting, with specific absorption rates (SARs) ranging from 3.7 to 325.9W/g Fe. Magnetic heating was conducted on iron oxide NPs synthesized in our laboratories (with average core sizes of 8, 11, 13, and 18nm), as well as commercially-available iron oxides (with average core sizes of 8, 9, and 16nm). The experimental magnetic coil system made it possible to isolate the effect of magnetic field parameters and independently study the effect on heat generation. The highest SAR values were found for the 18nm synthesized particles and the maghemite nanopowder. Magnetic field strengths were applied in the range of 15.1–47.7kA/m, with field frequencies ranging from 123 to 430kHz. The best heating was observed for the highest field strengths and frequencies tested, with results following trends predicted by the Rosensweig equation. An increase in solution viscosity led to lower heating rates in nanoparticle solutions, which can have significant implications for the application of magnetic fluid hyperthermia in vivo.

Heating Efficiency of Iron Oxide Nanoparticles in Hyperthermia: Effect of Preparation Conditions

The correlation between magneto-structural properties of iron oxide nanoparticles and their heating efficiency in ac magnetic fields is investigated. Nanoparticles with an average size of 13 nm and narrow size distribution are synthesized by coprecipitation of ferrous and ferric salts in an alkaline medium in which the salts ratio is systematically varied. To obtain nanoparticles with single-phase composition, the prepared samples are annealed at 200 °C. The lattice parameters of all nanoparticles deduced from X-ray diffraction analysis correspond to multiphase composition, i.e., to a mixture of magnetite and maghemite phases. However, low-temperature Mossbauer spectroscopy revealed complete transformation of magnetite to maghemite in annealed samples. The annealed samples show slightly higher value of specific loss power at a certain frequency and amplitude of ac magnetic field compared with other samples.

Magnetic Field Induced Enhanced Adsorption Efficiency of Iron Oxide Nanoparticles Based Magnetic Ferrofluid: A Preliminary Investigation

Solid state synthesis approach was used to prepare magnetic ferrofluid loaded with maghemite nanoparticles. This magnetic material was then used to study adsorptive removal of zinc ions in presence of applied magnetic field. Studies revealed that application of magnetic field results in remarkably increased adsorption efficiency of these ferrofluids.

Intracellular heating of living cells through Néel relaxation of magnetic nanoparticles

Maghemite and cobalt ferrite anionic magnetic nanoparticles enter tumor cells and can be used as heat sources when exposed to a high-frequency magnetic field. Comparative studies of the two particles enable to unravel the magnetic heating mechanisms (Néel relaxation vs. Brown relaxation) responsible for the cellular temperature rise, and also to establish a simple model, adjusted to the experimental results, allowing to predict the intracellular heating efficiency of iron oxide nanoparticles. Hence, we are able to derive the best nanoparticle design for a given material with a view to intracellular hyperthermia-based applications.