Magnetic nanoparticles Research Papers - Academia.edu (original) (raw)

In our study, hybrid gold/iron oxide loaded thermoresponsive micelles were synthesized for combined hyperthermia and chemotherapy, and optical imaging. Polymeric micelles made of amphiphilic block copolymer of poly(N-isopropylacrylamide-co-acrylamide)-block-poly( -caprolactone) were conjugated with gold/iron oxide particles which are self-assembled at the hydrophobic polymer core. Thermal sensitivity and magnetic and optical properties of the hybrid gold/iron oxide micelles were investigated for the combined therapy and optical imaging.

- by
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- Engineering, Imaging, Nanobiotechnology, Self Assembly

In this work, novel hydroxyl-modified magnetite nanocarriers are introduced as efficient host for methotrexate conjugation. The modification was based on the Micheal type addition reaction between tris(hydroxymethyl) aminomethane and acrylamidopropyl functionalized, silica-coated magnetite nanoparticle. The chemical structure characterization was carried out by FT-IR and the organic content was determined by CHN analysis. The topography was studied by SEM, TEM, AFM. DLS was performed to show particles' mean diameter. Furthermore, the magnetite properties of modified particles were evaluated by VSM and the crystallinity was proved by XRD. To illustrate the efficiency of the modified particles, the anti-cancer drug methotrexate was conjugated to hydroxyl groups through estric bond formation. The controlled release activity of established nanoparticles was evaluated in simulated cellular fluid. Later, the anti-cancer behavior of drug conjugated nanoparticles was evaluated in vitro in MCF-7 cell line which showed enhanced toxicity after 48 h. Conclusively, the modified nanoparticles have remarked as powerful carrier to be applied as an anti-cancer agent.

- by fatemeh farjadian
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- Drug delivery, Magnetic nanoparticles

The feasibility is examined of using high-gradient magnetic separation (HGMS) to recover about 8-nm magnetite nanoparticles that are tailored specifically to extract target solutes (polymer-coated nanoparticles for the extraction of soluble organic contaminants from water and phospholipid-coated particles for the selective extraction of proteins). A general model for nanoparticle capture based on calculating the limit of static nanoparticle buildup around the wires in an HGMS column is presented. Model predictions are compared successfully with experimental results from a bench-scale HGMS column for both the polymer-and phospholipid-coated particles. A minimum diameter for successful particle capture is derived for both individually dispersed nanoparticles and aggregates of nanoparticles. The individually dispersed polymer-coated nanoparticles are less easily captured in the HGMS column than are the phospholipid-coated particles, which exist as submicron aggregates.

- by Paul Laibinis
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- Chemical Engineering, Magnetic nanoparticles, Magnetic Nanoparticles, Generic model

Magnetic and NMR relaxivity properties of γ-Fe2O3 nanoparticles embedded into the walls of polyelectrolyte multilayer capsules and freely dispersed in a sodium borate buffer solution have been investigated. The different geometric distribution of both configurations provides the opportunity to study the relationship of water accessibility and magnetic properties of particles on the NMR relaxivity. Changes in their blocking temperature and average dipolar field were modeled as a function of packing fraction in the ensemble of free and entrapped nanoparticles. For free nanoparticles with relatively low concentration, relaxivity values increase with packing fraction according to an increase in the dipolar field and larger water accessibility. However, for embedded nanoparticles in the capsule wall, packing fractions should be limited to optimize the efficiency of this system as magnetic resonance imaging (MRI) contrast agent.

The unique properties of nanomaterials have propelled the field of nanomedicine. Nanomaterials have been used as drug delivery, imaging, and photothermal agents for diagnosis and therapy of diseases. Recently, photohyperthermia has attracted great interest from researchers and is actively being investigated as an alternative method of therapy for cancer and even bacteria. Photohyperthermia, or photothermal therapy, is the process of a photothermal agent absorbing light and converting it into heat for the destruction of malignant cells, which is due to elevated temperatures. This technique is non-invasive, can target specific diseased cells for minimal adverse side effects, and can be used in conjunction with other cancer treatments, such as chemotherapy. In this review, we will discuss different nanomaterials that have been implemented as photothermal agents for the treatment of various cancer and bacterial cells. The review will mainly focus on gold nanoparticles, magnetic nanoparticles, and carbon nanotubes. However, other nanomaterials, such as semiconductor nanoparticles and polymer composites, will be briefly discussed. In addition, the photothermal mechanism, current developments, dual imaging and therapy, and future perspectives of nanoparticle-based photohyperthermia will be presented.

This paper presents a low speed permanent magnetic based generator which is suitable for supplying generating power from bicycle motion and application in providing energy for bicycle front and rear lights or electronics devices.The dynamo have a hub axel, a hub housing rotatable mounted around the hub axel with bearing, a planetary drive that increases the rotational speed of the permanent magnet, and the power generating mechanism with coil fitted to hub axel that has connected to the output connector. In
such a hub dynamo, the magnet rotates faster than the bicycle wheel so that power output is high even at the normal bicycle speeds.

The demand projected in the world's population growth emphasis the advent of new technologies in the areas of energy consumption, environmental changes, and biomedical applications which play a major part in human life. One promising technology that fulfills the above demand is nanosciences and nanotechnology which play a crucial role at the nanoscale in energy, environment, and Lifesciences. Nanosciences plays a vital role in environmental monitoring, energy conversion, distribution, and storage as well as useful in gene therapy, drug delivery systems, and tissue engineering. The use of nanoscale materials and nanoparticles in these arenas eases the process flow and cost-effective with ecofriendly over the current conventional methods or applications. The various applications of nanosciences and Nanobiotechnology are versatile and find their applications in the fields of human diagnostics, bioremediation, waste management, medical devices, tissue engineering, green technology, environmental monitoring, emission control, electricity production and transmission loss, solar power, etc.

- by DR VISHNU KIRAN MANAM
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- Nanoelectronics, Nanomaterials, Nanowire, Nanotechnology

Magnetic separations are probably one of the most versatile separation processes in biotechnology as they are able to purify cells, viruses, proteins and nucleic acids directly from crude samples. The fast and gentle process in combination with its easy scale-up and automation provide unique advantages over other separation techniques. In the midst of this process are the magnetic adsorbents tailored for the envisioned target and whose complex synthesis spans over multiple fields of science. In this context, this article reviews both the synthesis and tailoring of magnetic adsorbents for bioseparations as well as their ultimate application.

- by Ana Azevedo
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- Magnetic nanoparticles

In the present work, Co 1−x Ni x Fe 2 O 4 (x = 0.02, 0.04, and 0.06 M) is prepared by sol-gel auto-combustion method and its structural, functional, magnetic, and morphological characteristics are analyzed. The peaks corresponding to the plane observed from XRD matches with JCPDS data of CoFe 2 O 4 (22-1086) and NiFe 2 O 4 (10-0325). It is noted that the average crystallite size decreases from 31 to 27 nm when the nickel concentration increases from 0.02 to 0.06 M, indicative of the incorporation of Ni 2+ ion in the cobalt ferrite lattice. FTIR analysis shows the presence of M↔O vibration at the tetrahedral and octahedral sites. Micro-Raman spectroscopy shows the stretching vibrations at 486.87 cm −1 (E g) and 696.96 cm −1 (A 1g), which are the characteristic vibrations of spinel ferrites. Magnetic studies show the variation in saturation magnetization (M S = 20.25, 9.41, 18.5 emu/g.) and coercivity (H C = 746.06, 953.03, 885.59 Oe) when the concentration of Ni 2+ ion increases from 0.02 to 0.06 M. The prepared nanoparticles show a ferromagnetic nature which is attributed to the creation of an antiparallel spin and the magnetic moment created by the cation at tetrahedral and octahedral sites. The surface morphology of samples is imaged by a field emission scanning electron microscope.

- by Raguram T and +1
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- Magnetic nanoparticles
- by Gennady Khomutov and +1
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- Magnetic nanoparticles, Magnetic Nanoparticles

Magnetically recyclable catalysts with magnetic nanoparticles (MNPs) are becoming a major trend towards sustainable catalysts. In this area, recyclable supported ruthenium complexes and ruthenium nanoparticles occupy a key place and present great advantages compared to classic catalysts. In this micro-review, attention is focused on the fabrication of MNP-supported ruthenium catalysts and their catalytic applications in various organic syntheses.

- by Didier Astruc
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- Organic Chemistry, Catalysis, Magnetic nanoparticles, Molecules

Scale reduction in materials leads to profound changes in their inner structure, which in turn greatly modifies the intrinsic electronic and optical properties. Magnetic ones do so. In the case of magnetic nanoparticles, these changes have meant the departure from some of the established laws governing the magnetic phenomena observed in bulk materials for the time being. The implications of these new phenomena on developing new technologies are manifold. On the one hand, the research done in magnetic nanoparticles over the last decades – more than two hundred thousand peer-reviewed publications - is now definitely moving from the theoretical grounds to the real applications arena, especially in medicine, as attested by both the increasing number of patents and companies formed around them. On the other hand, and also in relation to medical applications, the effects that many nanostructures could have on health still remain unknown, challenging the Food and Drug Agency (FDA) in USA or the European Medicines Agency (EMEA) to face continuous regulatory issues concerning the commercialisation of nanotechnology-based products and their eventual consumption, certainly slowing down the rate at which they would become available to the final consumer. The aim of this chapter is to present a concise overview of key concepts in magnetism applied to nanoparticles along with some of the instrumental techniques reasonably available in many laboratories to study the properties of magnetic nanoparticles. In accordance to the topic of this book, references to issues that could have a bearing on their potential uses in biomedicine and other related disciplines are also provided where appropriate. Finally, a good deal of what is said here applies to many types of magnetic materials, but given their relevance in medicine compared to other fine particle systems the text is rather focused on ferrimagnetic iron oxides, namely maghemite (g-Fe2O3) and magnetite (Fe3O4).

- by Daniel Ortega
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- Nanomaterials Characterization, Magnetic Materials, Nanomaterials, Nanoparticles

Inorganic nanoparticles have received increased attention in the recent past as potential diagnostic and therapeutic systems in the field of oncology. Inorganic nanoparticles have demonstrated successes in imaging and treatment of tumors both ex vivo and in vivo, with some promise towards clinical trials. This review primarily discusses progress in applications of inorganic nanoparticles for cancer imaging and treatment, with an emphasis on in vivo studies. Advances in the use of semiconductor fluorescent quantum dots, carbon nanotubes, gold nanoparticles (spheres, shells, rods, cages), iron oxide magnetic nanoparticles and ceramic nanoparticles in tumor targeting, imaging, photothermal therapy and drug delivery applications are discussed. Limitations and toxicity issues associated with inorganic nanoparticles in living organisms are also discussed.

- by Sutapa Barua and +1
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- Biomedical Engineering, Clinical Trial, Carbon Nanotubes, Drug delivery

This review focuses on the synthesis, protection, functionalization, characterization and with some applications of magnetic nanoparticles (MNPs). The review begins with an overview on magnetic property and single domain particles. The synthetic strategies developed for the generation of MNPs, with a focus on particle formation mechanism and recent modifications made on the synthesis of monodisperse samples of relatively large quantities are also discussed. Then, different methodologies for the protection and functionalization of the synthesized MNPs, together with the characterization techniques are explained. Finally, some of the recent industrial, biological, environmental and analyticals application of MNPs are briefly reviewed, and some future trends and perspectives in these research areas will be outlined.

- by Maryam Malik
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- Magnetic nanoparticles, Characterization

Citric acid coated magnetite nanoparticles (Fe 3 O 4 -Cit) have been synthesized for the removal of cadmium from aqueous solutions. As-prepared Fe 3 O 4 -Cit was characterized by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and through the determination of pH zpc . Several factors effecting the adsorption of Cd(II) ions on the surface of Fe 3 O 4 -Cit such as pH, temperature and contact time were investigated. The Cd(II) ions adsorption equilibrium on the Fe 3 O 4 -Cit were obtained by 35 min at the optimized pH 5. Kinetic study shows the Cd(II) adsorption onto Fe 3 O 4 -Cit follow the pseudo-second order kinetic model with R 2 > 0.997 at 308 K. The adsorption data was satisfactorily explained by Langmuir and Freundlich isotherm models. The experimental data found to be suitable linearity with Langmuir isotherm having maximum adsorption capacity (q m ) values in mg g −1 10.81, 11.45 and 12.56 at the 298 K, 303 K and 308 K, respectively. The correlation coefficient R 2 = 0.997 fully supports the favorability of Langmuir isotherm in adsorption process. The negative values of G • , −5.68, −6.31 and −6.95 kJ mol −l throughout the temperature at 298 K, 303 K and 308 K are indicating the feasibility of adsorption process on to Fe 3 O 4 -Cit was spontaneous in nature.

- by Ravindra Gautam
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- Kinetics, Adsorption, Magnetic nanoparticles, Magnetic Nanoparticles

E n esta memoria de Tesis Doctoral se presentan los resultados del estudio del efecto magnetocalórico y magnetovolúmico que se ha llevado a cabo en dos familias de compuestos ricos en Fe: aleaciones R 2 Fe 17 , sintetizadas en forma policristalina, y cintas amorfas de composición FeZrBCu. Estas aleaciones presentan transiciones magnéticas de segundo orden con temperaturas críticas en torno a temperatura ambiente.

- by Pablo Alvarez-Alonso and +1
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- Intermetallics, Amorphous Materials, Magnetic nanoparticles, Magnetocaloric Effect

During the past decade, nanotechnology with its rapid development has grabbed the attention of scientists, scholars, and engineers. Nanofluids are one of the surprising outcomes of this technology that could increase the efficiency of thermal systems remarkably. Nanofluids containing solid nanoparticles have a higher viscosity than common working fluids; hence, measuring the viscosity is necessary for designing thermal systems and estimating the required pumping power. In the current review study, an attempt has been made to cover the latest experimental studies performed on the viscosity of nanofluids. An experimental investigation is very vital for the analysis since the theoretical models usually underestimate the nanofluid viscosity. Through experiments, the real effects of volume fraction, temperature, particle size, and shape on the viscosity of nanofluids will be determined.

- by Mohammad Reza Safaei and +1
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- Heat Transfer, Nanoparticle, Nanomaterials, Nanoparticles

Free identical nano objects include metals, semiconductors, magnetic materials, polymers, bio molecules, are integrated together to form as multifunctional nanomaterials (MFNs), in which more than one behaviour can be rendered simultaneously. This summary showcases their exciting properties which are providing the emerging properties in applications like visualizing and targeting in drug delivery, recoverable and reusable photocatalytic materials. Various application areas, where the multifunctional nanomaterials are now getting the constant place in cutting edge technologies, are highlighted. And also in this, various multifunctional materials and their criteria involving during the integration of assorted materials based on their properties and to be applied according to the requirements of the applications are also explained in detail.

- by Muthusamy Sivakumar
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- Nanotechnology, Magnetic nanoparticles, Nanoscience, Magnetic separation

The Transition of frequencies and energy as they weaken and fade into lower frequency bands and dimensional portals.

Fluorescent optical probes have been intensively used in the area of bio-imaging. In this review article, we describe the recent advancements in the synthesis and application of bimodal magnetic–fluorescent probes for bioimaging. The bimodal probes consist of fluorescent [semiconducting quantum dots (e.g., CdSe/ZnS) or rare-earth doped (e.g., NaYF4:Yb,Er)] nanoparticles (NPs) and magnetic (iron oxide or gadolinium based) NPs for optical and magnetic resonance (MR) imaging. Microsc. Res. Tech., 2011. © 2010 Wiley-Liss, Inc.

Here, the researchers report on the synthesis of ion imprinted polymeric (IIP) nanoparticles using a thermal polymerization strategy, and their usage for the separation of Ni 2+ ion from water samples. The prepared Ni-IIP was characterized by colorimetry, FT-IR spectroscopy, and scanning electron microscopy. It was found that the particle size of the prepared particle to be 50-70 nm in diameter with the highly selective binding capability for Ni 2+ ion, with reasonable adsorption and desorption process. After preconcentration, bound ions can be eluted with an aqueous solution of hydrochloric acid, after their complexation with dimethylglyoxime, these ions can be quantified by UV-Vis absorption spectrophotometry. The effect of various parameters on the extraction efficiency including pH of sample solution, adsorption and leaching times, initial sample volume, concentration and volume of eluent were investigated. In selectivity study, it was found that imprinting causes increased affinity of the prepared IIP toward Ni 2+ ion over other ions such as Na + , K + , Ag + , Co 2+ , Cu 2+ , Cd 2+ , Hg 2+ , Pb 2+ , Zn 2+ , Mn 2+ , Mg 2+ , Cr 3+ , and Fe 3+ . The prepared IIP can be used and regenerated for at least eight times without any significant decrease in binding affinities. The prepared IIP is considered to be promising and selective sorbent for solidphase extraction and preconcentration of Ni 2+ ion from different water samples.

- by Hamid Reza Rajabi
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- Nanotechnology, Photocatalysis, Flow Injection Analysis, Magnetic nanoparticles

Nanotechnology is an emerging field that covers a wide range of technologies which are presently under development in nanoscale. It plays a major role in the development of innovative methods to produce new products, to substitute existing production equipment and to reformulate new materials and chemicals with improved performance resulting in less consumption of energy and materials and reduced harm to the environment as well as environmental remediation. Although, reduced consumption of energy and materials benefits the environment, nanotechnology will give possibilities to remediate problems associated with the existing processes in a more sustainable way. Environmental applications of nanotechnology address the development of solutions to the existing environmental problems, preventive measures for future problems resulting from the interactions of energy and materials with the environment, and any possible risks that may be posed by nanotechnology itself. This article gives a comprehensive review on the ongoing research and development activities on environmental remediation by nanotechnology. First, the essential aspects of environmental problems are reviewed and then the application of nanotechnology to the compounds, which can serve as environmental cleaning, is described. Various environmental treatments and remediations using different types of nanostructured materials from air,

- by G.Ali Mansoori
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- Environmental Studies, Dendrimers, Micelles, Magnetic nanoparticles

The labeling of stem cells with iron oxide nanoparticles is increasingly used to enable MRI cell tracking and magnetic cell manipulation, stimulating the fi elds of tissue engineering and cell therapy. However, the impact of magnetic labeling on stem-cell differentiation is still controversial. One compromising factor for successful differentiation may arise from early interactions of nanoparticles with cells during the labeling procedure. It is hypothesized that the lack of control over nanoparticle colloidal stability in biological media may lead to undesirable nanoparticle localization, overestimation of cellular uptake, misleading MRI cell tracking, and further impairment of differentia-

A series of CoFe 2 O 4 nanoparticles were formed through a variant hydrothermal synthesis based in a self-assembly oil-water system in autoclaves at 200 °C in the presence of octadecylamine and the trivalent iron and cobalt acetylacetonates. The variation of the water content, the different valence of cobalt precursor (Co(II) and Co(III)) as well as Fe:

- by Orestis Kalogirou
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- Magnetic nanoparticles

- by Sandwip Dey
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- Materials Science, Biomedical Engineering, Clinical Trial, Carbon Nanotubes
- by Mika Sillanpää
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- Chemical Engineering, Water Treatment, Adsorption, Magnetic nanoparticles

Nanotechnology is rapidly expanding research area, encompassing the development of man-made materials in nanometer size range. Nanoscale drug delivery system using various nanomaterials is emerging technology for the rational delivery of many chemotherapeutic agents. Nanoparticles attracted the scientists across many disciplines to engineer many desired properties that might otherwise be incompatible on a single device. Formulation scientists are facing the challenges such as poor solubility and bioavailability of the newly invented drugs. One of the approaches to face the above challenge is to develop the particulate carrier system. Solid lipid nanoparticle or liposphere or nanosphere system is the most feasible particulate carrier system which is an alternative to nanoemulsions, liposomes and polymeric nanoparticles. This system offers added advantages in comparison to other related particulate drug delivery systems. The present review emphasizes on various basic and applied aspects of solid lipid nanoparticles in novel drug delivery system especially techniques involved in their production, characterization and various applications. It also focuses on the drug loading capacity, drug incorporation and factors affecting drug release from this colloidal system.

Pollution of industrial wastewaters containing dyes is a major concern for health in many countries, calling for advanced remediation techniques. Here, we review dye classification, toxicity, and removal with focus on adsorption using nanomaterials and magnetic nanoparticles. We present isotherm modeling and kinetic studies. We discuss factors controlling dye adsorption, such as pH, dye concentration, adsorbent amount, and temperature. Adsorption using magnetic nanoparticles appear as a simple and cost-effective technique. Removal efficiency increases with adsorbent concentration but declines sharply with increasing pH. Temperature is also highly influencing the removal.

These analytes are often of biological origin like DNAs of bacteria or viruses, or proteins which are generated from the immune system (antibodies, antigens) of infected or contaminated living organisms. Such analytes can also be simple molecules like glucose or pollutants when a biological receptor unit with particular specificity is available. One of many other challenges in biosensor development is the efficient signal capture of the biological recognition event (transduction). Such transducers translate the interaction of the analyte with the biological element into electrochemical, electrochemiluminescent, magnetic, gravimetric, or optical signals. In order to increase sensitivities and to lower detection limits down to even individual molecules, nanomaterials are promising candidates due to the possibility to immobilize an enhanced quantity of bioreceptor units at reduced volumes and even to act itself as transduction element. Among such nanomaterials, gold nanoparticles, semiconductor quantum dots, polymer nanoparticles, carbon nanotubes, nanodiamonds, and graphene are intensively studied. Due to the vast evolution of this research field, this review summarizes in a non-exhaustive way the advantages of nanomaterials by focusing on nano-objects which provide further beneficial properties than "just" an enhanced surface area.

- by Serge Cosnier
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- Biosensors, Quantum Dots, Magnetic nanoparticles, Gold Nanoparticles

Magnetic separation is a versatile technique used in sample preparation for diagnostic purpose. For such application, an externalmagnetic field is applied to drive the separation of target entity (e.g. bacteria, viruses, parasites and cancer cells) from a complex raw sample in order to ease the subsequent task(s) for disease diagnosis. This separation process not only can be achieved via the utilization of high magnetic field gradient, but also, in most cases, low magnetic field gradient with magnitude less than 100 T m21 is equally feasible. It is the aim of this review paper to summarize the usage of both high gradient magnetic separation and low gradient magnetic separation (LGMS) techniques in this area of research. It is noteworthy that effectiveness of the magnetic separation process not only determines the outcome of a diagnosis but also directly influences its accuracy aswell as sensing time involved. Therefore, understanding the factors that simultaneously influence the efficiency of both magnetic separation process and target detection is necessary. Moreover, for LGMS, there are several important considerations that should be taken into account in order to ensure its successful implementation. Hence, this review paper aims to provide an overview to relate all this crucial information by linking the magnetic separation theory to biomedical diagnostic applications.

- by Yeap Swee Pin
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- Microfluidics, Magnetic nanoparticles, Separation processes, Colloidal Systems

The aim of the present work was to demonstrate the possibility of selective detection of nanoparticle contrast agents (NPCAs) on diagnostic echographic images by exploiting the second harmonic component they introduce in the spectra of corresponding ultrasound signals, as a consequence of nonlinear distortion during ultrasound propagation. We employed silica nanospheres (SiNSs) of variable diameter (160 nm, 330 nm, and 660 nm) dispersed in different volume concentrations (range 0.07-0.8%) in agarose gel samples that were automatically scanned through a digital ecograph using narrow-band ultrasound pulses at 6.6 MHz and variable mechanical index (MI range 0.2-0.6). In the first part of the study, the intensity peaks of four different spectral components of the backscattered signal were considered: fundamental (detected in correspondence of the incident ultrasound frequency), subharmonic (detected at half of the fundamental frequency), ultra harmonic (detected at 1.5 times the fundamental frequency), and second harmonic (detected at twice the fundamental frequency). Subsequently, based on the experimental results of the first part of the study and on our recently reported findings, the focus was moved to a detailed comparison between subharmonic and second harmonic trend, which were determined as a function of nanoparticle composition, sample concentration, and MI. The experiments were also repeated on different agarose samples, containing SiNSs covered by an outer shell of smaller magnetic nanoparticles, made of either iron oxide (IO) or FePt-IO nanocrystals. Obtained results show that this new ultrasound-based method for NPCA imaging has a detection sensitivity similar to that of our previously introduced subharmonic-based technique in the presence of 330-nm SiNSs, but performs significantly better in the detection of both the types of "dual mode" NPCAs. The fact that the reported detection method was optimized for identification of 330-nm SiNSs (a sort of "ideal" size for the development of novel tumor-targeting NPCAs) and that the magnetically coated particles are detectable also through magnetic resonance imaging makes the presented second harmonic ultrasound method a valuable solution for the introduction of new protocols for multimodal molecular diagnoses employing only nonionizing radiations.

- by Andrea Ragusa and +1
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- Harmonic Analysis, Ultrasound Imaging, Magnetic Resonance Imaging, Imaging

This paper elaborates on the findings of study on the effect of Fe2O3/Kerosene nanofluid to the copper closed-loop oscillating heat pipe under the magnetic field for inclination angles ranging from 0° to 90°, under different heat inputs (10–90 W). The heat pipe’s heat transfer coefficient was measured without and with the magnetic field. Moreover, the vapor temperature was assessed directly at the center of the oscillating heat pipe by exposing the ferro-nano particles to a magnetic field. It was shown that Fe2O3 nanoparticles could improve the thermal resistance and subsequently thermal performance as well as the pipe’s heat transfer coefficient, especially under the magnetic field. The heat pipe’s heat transfer coefficient increased as the input heat flux increased. The results also demonstrated that the heat pipe’s inclination angle had a significant effect on performance of heat pipe. The critical angle was 75° as the heat transfer coefficient increased due to higher inclination angle.

- by Mohammad Reza Safaei and +1
- •
- Heat Transfer, Nanoparticle, Nanoparticles, Nanoscale heat transfer

In this report a simple and eco-friendly biosynthesis of silver
nanoparticles using Pomegranate peel extract as the reducing agent
from 1 mM AgNO3 had been investigated. The formation of silver
nanoparticles was characterized by UV-Vis spectrum, Fourier
Transform Infrared Spectroscopy (FT-IR) and Scanning Electron
Microscopic (SEM) analysis. The UV-Vis spectra results show a
strong resonance centered on the surface of silver nanoparticles
(AgNPs) at 371 nm. The Fourier Transformation Infrared
Spectroscopy spectral study demonstrates pomegranate peel extract
acted as the reducing agent. The scanning electron microscopic
(SEM) analysis shows nanoparticles with the average particles size
ranges about 5-50 nm. Further the antibacterial activity of AgNPs
was evaluated against Staphylococcus aureus, Pseudomonas
aeruginosa and Escherichia coli pathogens. This route is rapid,
simple, without any hazardous chemicals as reducing or stabilizing
agents and economical to synthesize AgNPs.

A B S T R A C T In this work, a facile chemical synthesis of polystyrene (PS) added cobalt ferrite (CoFe 2 O 4) magnetic nanoparticles by co-precipitation method is reported and the role of PS concentrations (1, 2, 3, 4 and 5 wt%) on the structural, morphological, dielectric and magnetic properties of CoFe 2 O 4 nanoparticles is investigated. Formation of single phase cubic inverse spinel structure is confirmed by X-ray diffraction and Raman spectral analyses. Transmission electron microscopy studies show that the size of CoFe 2 O 4 nanoparticles can be controlled by varying of PS concentration. Dielectric constant is enhanced due to increase in the PS concentrations in CoFe 2 O 4 nanoparticles. Vibrating sample magnetometer measurements elucidate the enhanced saturation magnetization, coercivity and remanent magnetization in 1, 2 and 3 wt% of PS added CoFe 2 O 4 nanoparticles. Hence the results obtained in this work evidently show that the addition of PS as a surfactant in the synthesis of CoFe 2 O 4 nanoparticles remarkably modify the size of the particles.

- by Vadivel Bala
- •
- Magnetic nanoparticles

We have developed a multi-layer approach for the synthesis of water-dispersible superparamagnetic iron oxide nanoparticles for hyperthermia, magnetic resonance imaging (MRI) and drug delivery applications. In this approach, iron oxide core nanoparticles were obtained by precipitation of iron salts in the presence of ammonia and provided β-cyclodextrin and pluronic polymer (F127) coatings. This formulation (F127250) was highly water dispersible which allowed encapsulation of the anti-cancer drug(s) in β-cyclodextrin and pluronic polymer for sustained drug release. The F127250 formulation has exhibited superior hyperthermia effects over time under alternating magnetic field compared to pure magnetic nanoparticles (MNP) and β-cyclodextrin coated nanoparticles (CD200). Additionally, the improved MRI characteristics were also observed for the F127250 formulation in agar gel and in cisplatin resistant ovarian cancer cells (A12780CP) compared to MNP and CD200 formulations. Furthermore, the drug loaded formulation of F127250 exhibited many folds of imaging contrast properties. Due to the internalization capacity of the F127250 formulation, its curcumin loaded formulation (F127250-CUR) exhibited almost equivalent inhibition effects on A2780CP (ovarian), MDA-MB-231 (breast), and PC3 (prostate) cancer cells even though curcumin release was only 40%. The improved therapeutic effects were verified by examining molecular effects using Western blotting and transmission electron microscopic (TEM) studies. F127250-CUR also exhibited haemocompatibility, suggesting a nanochemo-therapuetic agent for cancer therapy.

- by Yallapu Murali Mohan
- •
- Engineering, Materials Chemistry, Biomaterials, Magnetic Resonance Imaging

Nanohybrid of graphene oxide (GO) and azide-modified Fe3O4 nanoparticles (NPs) were fabricated using click reaction. First, Fe3O4 NPs were modified by 3-azidopropionic acid. Then, click-coupling of azide-modified Fe3O4 NPs with alkyne-functionalized GO was carried out in the presence of CuSO4·5H2O and sodium l-ascorbate at room temperature. The attachment of Fe3O4 NPs onto the graphene nanosheets was confirmed by Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy, thermogravimetric analysis, energy dispersive X-ray spectrometry and X-ray diffraction spectrometry. As the FTIR spectroscopy and energy dispersive X-ray spectrometry analysis showed, the final magnetic graphene nanosheets were also reduced by sodium ascorbate which is a merit for click-coupling reactions. The specific saturation magnetization of the Fe3O4-clicked GO was 44.3 emu g−1. The synthesized hybrid was used in the adsorption of methylene blue and congo red (CR). The adsorption capacities in the studied concentration range were 109.5 and 98.8 mg g−1 for methylene blue and CR, respectively.

- by Mina Namvari and +1
- •
- Click chemistry, Magnetic nanoparticles, Graphene Oxide

Magnetic nanoparticles heated by an alternating magnetic field could be used to treat cancers, either alone or in combination with radiotherapy or chemotherapy. However, direct intratumoral injections suffer from tumor incongruence and invasiveness, typically leaving undertreated regions, which lead to cancer regrowth. Intravenous injection more faithfully loads tumors, but, so far, it has been difficult achieving the necessary concentration in tumors before systemic toxicity occurs. Here, we describe use of a magnetic nanoparticle that, with a well-tolerated intravenous dose, achieved a tumor concentration of 1.9 mg Fe/g tumor in a subcutaneous squamous cell carcinoma mouse model, with a tumor to non-tumor ratio . 16. With an applied field of 38 kA/m at 980 kHz, tumors could be heated to 60°C in 2 minutes, durably ablating them with millimeter (mm) precision, leaving surrounding tissue intact.

- by Sharmila Sarkar
- •
- Physics, Cancer, Hyperthermia, Nanotechnology

Magnetic nanoparticles (MNPs) which exhibit magnetic and catalytic bifunctionalities have been widely accepted as one of the most promising nanoagents used in water purification processes. However , due to the magnetic dipole-dipole interaction, MNPs can easily lose their colloidal stability and tend to agglomerate. Thus, it is necessary to enhance their colloidal stability in order to maintain the desired high specific surface area. Meanwhile, in order to successfully utilize MNPs for environmental engineering applications , an effective magnetic separation technology has to be developed. This step is to ensure the MNPs that have been used for pollutant removal can be fully reharvested back. Unfortunately, it was recently highlighted that there exists a conflicting role between colloidal stability and magnetic separability of the MNPs, whereby the more colloidally stable the particle is, the harder for it to be magnetically separated. In other words, attaining a win-win scenario in which the MNPs possess both good colloidal stability and fast magnetic separation rate becomes challenging. Such phenomenon has to be thoroughly understood as the colloidal stability and the magnetic separability of MNPs play a pivotal role on affecting their effective implementation in water purification processes. Accordingly, it is the aim of this paper to provide reviews on (i) the colloidal stability and (ii) the magnetic separation of MNPs, as well as to provide insights on (iii) their conflicting relationship based on recent research findings.

Iron oxide nanoparticles (IONPs) occupy a privileged position among magnetic nanomaterials with potential applications in medicine and biology. They have been widely used in preclinical experiments for imaging contrast enhancement, magnetic resonance, immunoassays, cell tracking, tissue repair, magnetic hyperthermia and drug delivery. Despite these promising results, their successful translation into a clinical setting is strongly dependent upon their physicochemical properties, toxicity and functionalization possibilities. Currently, IONPs-based medical applications are limited to the use of non-functionalized IONPs smaller than 100 nm, with overall narrow particle size distribution, so that the particles have uniform physical and chemical properties. However, the main entry of IONPs into the scene of medical application will surely arise from their functionalization possibilities that will provide them with the capacity to target specific cells within the body, and hence to play a role in the development of specific therapies. In this review, we offer an overview of their basic physicochemical design parameters, giving an account of the progress made in their functionalization and current clinical applications. We place special emphasis on past and present clinical trials.

- by Daniel Ortega
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- Health Sciences, Cancer, Magnetic Resonance Imaging, Magnetic Materials

Ebola continues to rage in West Africa. In the absence of an approved vaccine or treatment, the priority in controlling this epidemic is to promptly identify and isolate infected individuals. To this end, a rapid, highly sensitive, and easy-to-use test for Ebola diagnosis is urgently needed. Here, by using Fe3O4 magnetic nanoparticle (MNP) as a nanozyme probe, we developed a MNP-based immunochromatographic strip (Nanozyme-strip), which detects the glycoprotein of Ebola virus (EBOV) as low as 1 ng/mL, which is 100-fold more sensitive than the standard strip method. The sensitivity of the Nanozyme-strip for EBOV detection and diagnostic accuracy for New Bunyavirus clinical samples is comparable with ELISA, but is much faster (within 30 min) and simpler (without need of specialist facilities). The results demonstrate that the Nanozyme-strip test can rapidly and sensitively detect EBOV, providing a valuable simple screening tool for diagnosis of infection in Ebola-stricken areas.

- by Kelong Fan
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- Magnetic nanoparticles, Iron Oxide Nanoparticles, Ebola virus diagnosis, Nanozyme

Zinc-ferrite nanoparticles were prepared using the hydrothermal and the sol-gel methods.
ZnFe2O4 nanoparticles with a spinel structure were formed by using both approaches, which was
confirmed through X-ray diffraction. Although both types of ZnFe2O4 nanoparticles showed similar
morphologies and particle sizes, the saturation magnetization of the ZnFe2O4 prepared using
the hydrothermal method was about 10 times higher than that of the ZnFe2O4 prepared using
the sol-gel method. Through the Rietveld refinement analysis, we were able to conclude that the
enhanced magnetic property of ZnFe2O4 could be attributed to the cation inversion induced during
the hydrothermal synthesis process.

In this work, nanoparticles based on magnetite have been prepared by sol-gel and precipitation methods. In the first case two variants have been applied: by growing of sol starting from nitrate precursor and ethylene glycol as dissolvent and to control the reduction process and force hydrolysis and steric control prepared from ferrum sulfate precursor and sodium citrate. In the second case the starting material was sulfate precursor, amonium hydroxide as precipitaing agent and ethylene glycol as surfactant. The samples have been characterized by X-ray diffraction technique (XRD), adsorption-desorption of N (BET 2 equation model) and Mössbauer spectroscopy. XRD patterns of all samples showed typical peaks of magnetite which were detected in the following positions: 30,06 º, 35,42 º, 62,55 º. 2 Average specific surface quantified by BET method was ranging from 40 to 50 m /g with a* Ingeniería, Av. Túpac Amaru 210, Rímac, Lima-Perú.

- by Jaime Vega Chacon and +1
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- Magnetic nanoparticles, Iron Oxide Nanoparticles

"Iron oxides nanoparticles with different sizes are successfully synthesized using sol-gel method. X-ray diffraction (XRD) and Mössbauer spectroscopy show that the obtained nanoparticles are mainly composed of maghemite phase (-Fe2O3). XRD and transmission electron microscopy (TEM) results suggest that the nanoparticles have sizes ranging from 14 to 30 nm, which are indeed confirmed by large magnetic saturation and high blocking
temperature. At room temperature, the observation of a on-negligible coercive field suggests that the particles are ferro/ferrimagnetic. The specific absorption rate (SAR) under an
alternating magnetic field is investigated as a function of size, frequency and amplitude of the applied magnetic field. A mean heating efficiency of 30 W/g is obtained for the smallest
particles at 110 kHz and 190 Oe, whereas further increase of particle size does not improve significantly the heating efficiency."

Nickel ferrite (NiFe2O4) nanoparticles are synthesized by an easy and affordable strategy using nickel chloride, Iron chloride, sodium hydroxide and oxalic acid as oxide source via chemical co-precipitation technique. The structure of the pure and doped NiFe2O4 nanoparticles is investigated XRD affirmed the arrangement of inverse spinel structure and space group Fd3m and the particle size is observed to be 23-45 nm. The particle size is found to decrease with doping of oxalic acid with NiFe2O4 nanoparticles. The appearance of different functional gatherings are affirmed by Fourier transform infrared spectroscopic (FTIR) study and composition elements of nanoparticles are carried out by Energy dispersive X-ray analysis(EDX). The optical properties and band gap energy are observed through UV-Visible spectroscopy. The morphology and micro structure of the nanoparticles are checked by scanning electron microscope (SEM). The Nickel ferrite nanoparticles have showed super-paramagnetic nature at room temperature.

- by gurumoorthy ms and +1
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- Magnetic nanoparticles, Core shell Nanoparticles

The facile green synthesis method has been employed for the synthesis of biocompatible Fe3O4 magnetic nanoparticles (MNPs) using green tea extract. The effective reduction of ferric ions (Fe3+) were done using an aqueous green tea extract where it acts as reducing as well as a capping agent. The effect of iron precursor to green tea extract ratio and the reaction temperature was studied. The MNPs were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, dynamic light scattering, and vibrating sample magnetometer. It was observed that the reaction temperature strongly affects the magnetic and structural properties of MNPs. The magnetic measurements study showed that Fe3O4 MNPs are superparamagnetic at 300 K, while at 60 K have ferromagnetic as well as superparamagnetic contributions.

- by Vijay Karade
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- Magnetic nanoparticles, Green Tea, Green Synthesis, Magnetism and Magnetic Materials

A facile and rapid synthesis of core−shell type magnetite-chitosan microsphere decorated with silver nano-particles (MCSM) is described. The composition and structure of the as-synthesized microsphere characterized by various spectroscopic and microscopic techniques demonstrated formation of 3.63 ± 0.76 μm MCSM with decoration of silver nanoparticles (AgNPs) having 16 ± 2.5 nm size. The thermogravimetric analysis (TGA) data showed good thermal stability, whereas vibrating sample magnetometry (VSM) analysis indicated the superparamagnetic behavior of the as-synthesized microsphere. The adsorptive removal and antimicrobial property of MCSM was explored for eco-friendly and cost-effective water purification. The MCSM removed 99.99% microbial contaminants and 99.5% of dyes from single as well as multicomponent systems from water bodies efficiently. Furthermore, the dye removal capacity of MCSM (q e = 271.2 ± 14.5 mg/g) was found to be higher compared to the other nanoadsorbents attributing to the high effective surface area of the microsphere and plenty of functional groups of shell structure of chitosan favored binding of dyes on MCSM. Moreover, the adsorbed dyes were desorbed from MCSM at higher pH values and regenerated MCSM was used for next cycle of dye removal. The magnetic behavior of MCSM facilitated easy separation using external magnetic field leading to recycling and reuse, whereas decoration of AgNPs on the microsphere inhibited the bacterial growth. The long-term antibacterial activity of MCSM significantly improved the antifouling property to inhibit the biofilm formation on MCSM. The proposed core−shell type MCSM thus provides a promising opportunity for cost-effective water purification.