Preparation Of Magnetic Nanoparticles Research Articles

Determination of the Size of Complex Iron Oxide Nanoparticles Using Various Physical Experimental Methods

A series of organically coated iron oxide nanoparticles obtained via the thermal decomposition of iron–oleate complexes via a “heating-up” process were investigated using the methods of transmission electron microscopy, X-ray diffraction and fine magnetometry, accompanied by elaborate mathematical analysis. The analysis of dependencies of field dependencies on the magnetization of the shape and broadening of maxima of X-ray diffraction patterns and fine refinement of transmission electron microscopy data allowed us to demonstrate that all of the samples under consideration had a tripartite structure: (i) the magnetic crystalline core of iron oxide, (ii) the paramagnetic stratum of amorphous iron oxide and (iii) the organic coater. The new approach toward synthesis for organic coated iron oxide shows that it could be applied to the preparation of magnetic nanoparticles with different and controlled magnetic properties and sizes depending on necessary applications, especially biomedical.

Barium hexaferrite nanoplatelets with polyphenol coatings for versatile applications as a stable, magnetic, and antimicrobial colloid

Colloidal stabilization of magnetic nanoparticles is one of the most important steps in the preparation of magnetic nanoparticles for potential biomedical applications. A special kind of magnetic nanoparticle are barium hexaferrite nanoplatelets (BSHF NPLs) with a hexagonal shape and a permanent magnetic moment. One strategy for the stabilization of BHF in aqueous media is to use coatings. In our research, we used an eco-friendly tannic acid, as a coating on BSHF NPLs. As-prepared BSHF NPLs coated with tannic acid were examined with transmission electron microscopy, infrared and UV-Vis spectroscopy, electro-kinetic measurements, and their room-temperature magnetic properties were measured. Stable colloids were tested in two biological complex media and antimicrobial properties of the material were examined. To enhance the antimicrobial properties of our material, we used tannic acid as a platform for the in-situ production of silver on BSHF NPLs. New hybrid material with silver also possesses magnetic properties and excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus.

From Biowaste to Lab-Bench: Low-Cost Magnetic Iron Oxide Nanoparticles for RNA Extraction and SARS-CoV-2 Diagnostics.

The gold standard for diagnostics of SARS-CoV-2 (COVID-19) virus is based on real-time polymerase chain reaction (RT-PCR) using centralized PCR facilities and commercial viral RNA extraction kits. One of the key components of these kits are magnetic beads composed of silica coated magnetic iron oxide (Fe2O3 or Fe3O4) nanoparticles, needed for the selective extraction of RNA. At the beginning of the pandemic in 2019, due to a high demand across the world there were severe shortages of many reagents and consumables, including these magnetic beads required for testing for SARS-CoV-2. Laboratories needed to source these products elsewhere, preferably at a comparable or lower cost. Here, we describe the development of a simple, low-cost and scalable preparation of magnetic nanoparticles (MNPs) from biowaste and demonstrate their successful application in viral RNA extraction and the detection of COVID-19. These MNPs have a unique nanoplatelet shape with a high surface area, which are beneficial features, expected to provide improved RNA adsorption, better dispersion and processing ability compared with commercial spherical magnetic beads. Their performance in COVID-19 RNA extraction was evaluated in comparison with commercial magnetic beads and the results presented here showed comparable results for high throughput PCR analysis. The presented magnetic nanoplatelets generated from biomass waste are safe, low-cost, simple to produce in large scale and could provide a significantly reduced cost of nucleic acid extraction for SARS-CoV-2 and other DNA and RNA viruses.

Preparation of magnetic nanoparticles as photo‒Fenton catalysts by a hydrothermal‒assisted thermal treatment method

The magnetic CoFe2O4 nanoparticles, prepared by hydrothermal method combining with the heat treatment at 600oC, were used to act as a photo‒Fenton catalyst in the methylene blue (MB) degradation reaction. The composition, structure, and surface morphology of the prepared materials were studied by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) spectroscopy. The optical properties of CoFe2O4 before and after calcination, analyzed by UV-Vis diffuse reflectance (DRS) spectroscopy, demonstrated that after heating at 600oC, the structure and crystallinity of CoFe2O4 were increased. The calcination process also caused the CoFe2O4 sintering to grow to a larger size, thereby reducing the surface area of the CoFe2O4 after calcination compared to the original ones. This value was determined through nitrogen the adsorption‒desorption isotherms curve. The magnetism of CoFe2O4 before and after calcination was studied by vibrating sample magnetometer (VSM). After sintering at 600oC, the saturation magnetization (Ms) and residual magnetism (Mr) of CoFe2O4 were higher than those of the original. The Fenton photocatalytic performance was evaluated by MB degradation reaction under UVA radiation in the presence of oxalic acid as an active free radical generating agent. In the methylene blue degradation reaction at room temperature, the prepared CoFe2O4 catalyst showed the maximum degradation efficiency of 97% for MB and the reaction yields were almost unchanged after three consecutive reactions. This method promised in making ferrite materials for water treatment based on some advantages such as simple process, low cost, and environmentally friendly solvent usage.

Preparation and Characterization of Superparamagnetic Iron Oxide Nanoparticles (Fe3O4) for Biological Applications

Superparamagnetic iron oxide nanoparticles (SPIONs) are developed considering the importance of this class of in different fields of biochemical and biomedical applications owing to their distinctive chemical and physical properties. In this work, the preparation of iron oxide nanoparticles (SPIONs (using Co-precipitation method has been done as the most commonly used wet chemical method of magnetic nanoparticles preparation for biological applications. The SPIONs synthesis was based on sodium hydroxide (NaOH) mediated precipitation of Fe3+ and Fe2+ salts in an aqueous solution using trisodium citrate as surfactant within a closed system. The size and stability of the magnetite nanoparticles were carefully controlled using different chemical and physical parameters in order to obtain the SPIONs with small particle size and distribution that is needed for biomedical applications. The synthesized Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), and Zeta potential analysis (Zp). XRD pattern showed the presence of peaks corresponding to the phase of magnetite Fe3O4. Moreover, SEM and TEM results revealed spherical particles with a mean diameter of ≥ 5 nm. The monodispersed SPIONs were successfully prepared with a mean hydrodynamic size of 209.32 nm at a stirring speed of 900 rpm and NaOH concentration of 1.2 gm. The results showed that the particle size is considerably dependent on the stirring rate and NaOH concentration. Fe3O4 nanoparticles exhibited superparamagnetic behavior and the saturation magnetization was around 50 emu/g.

An Advanced Thermal Decomposition Method to Produce Magnetic Nanoparticles with Ultrahigh Heating Efficiency for Systemic Magnetic Hyperthermia.

Due to the limited heating efficiency of available magnetic nanoparticles, it is difficult to achieve therapeutic temperatures above 44°C in relatively inaccessible tumors during magnetic hyperthermia following systemic administration of nanoparticles at clinical dosage (≤10mg kg-1 ). To address this, a method for the preparation of magnetic nanoparticles with ultrahigh heating capacity in the presence of an alternating magnetic field (AMF) is presented. The low nitrogen flow rate of 10mL min-1 during the thermal decomposition reaction results in cobalt-doped nanoparticles with a magnetite (Fe3 O4 ) core and a maghemite (γ-Fe2 O3 ) shell that exhibit the highest intrinsic loss power reported to date of 47.5 nH m2 kg-1 . The heating efficiency of these nanoparticles correlates positively with increasing shell thickness, which can be controlled by the flow rate of nitrogen. Intravenous injection of nanoparticles at a low dose of 4mg kg-1 elevates intratumoral temperatures to 50°C in mice-bearing subcutaneous and metastatic cancer grafts during exposure to AMF. This approach can also be applied to the synthesis of other metal-doped nanoparticles with core-shell structures. Consequently, this method can potentially be used for the development of novel nanoparticles with high heating performance, further advancing systemic magnetic hyperthermia for cancer treatment.

Synergic Temperature Effect of Star-like Monodisperse Iron Oxide Nanoparticles and Their Related Responses in Normal and Cancer Cells.

Magnetic nanoparticle (MNP) anisotropy has been tailored by the preparation of MNPs having different shapes (star-like, cubic, and polyhedral) using a self-modified rapid hot-injection process. The surface modification of MNPs was performed through etidronic ligand grafting with a strong binding affinity to mixed metal oxides, ensuring sufficient colloidal stability, surface protection, and minimized aggregation and interparticle interactions. The heating effect was induced by contactless external stimulation through the action of an alternating magnetic field and NIR laser radiation (808 nm). The efficacy of the energy conversion was evaluated as a function of the particle shape, concentration, and external stimuli parameters. In turn, the most efficient star-like particles have been selected to study their response in contact with normal and cancer cells. It was found that the star-like MNPs (Fe3O4 SL-NPs) at 2 mg/mL concentration induce necrosis and significantly alter cell cycle progression, while 0.5 mg/mL can stimulate the antioxidative and anti-inflammatory response in normal cells. A biologically relevant heating effect leading to heat-mediated cell death was achieved at a 2 mg/mL concentration of star-like particles and was enhanced by the addition of ascorbic acid (AA). AA-mediated photomagnetic hyperthermia can lead to the modulation of the heat-shock response in cancer cells that depends on the genotypic and phenotypic variations of cell lines.

Fabrication of a magnetic alginate-silk fibroin hydrogel, containing halloysite nanotubes as a novel nanocomposite for biological and hyperthermia applications

In this study, the main focus was on designing and synthesizing a novel magnetic nanobiocomposite and its application in hyperthermia cancer treatment. Regarding this aim, sodium alginate (SA) hydrogel with CaCl2 cross-linker formed and modified by silk fibroin (SF) natural polymer and halloysite nanotubes (HNTs), followed by in situ Fe3O4 magnetic nanoparticles preparation. No important differences were detected in red blood cells (RBCs) hemolysis, confirming the high blood compatibility of the treated erythrocytes with this nanobiocomposite. Moreover, the synthesized SA hydrogel/SF/HNTs/Fe3O4 nanobiocomposite does not demonstrate toxicity toward HEK293T normal cell line after 48 and 72 h. The anticancer property of SA hydrogel/SF/HNTs/Fe3O4 nanobiocomposites against breast cancer cell lines was corroborated. The magnetic saturation of the mentioned magnetic nanobiocomposite was 15.96 emu g−1. The specific absorption rate (SAR) was measured to be 22.3 W g−1 by applying an alternating magnetic field (AMF). This novel nanobiocomposite could perform efficiently in the magnetic fluid hyperthermia process, according to the obtained results.

Synthesis and Applications of Biopolymer /FeO Nanocomposites: A Review

Magnetic oxide nanoparticles have engaged most consideration due to their rare character, such as easy separation, surface-to- volume ratio, paramagnetic and high surface area. Natural biopolymers, namely, (Chitosan, Guar-Gum, Tamarind, Alginate, Dextran, Pectin) have posed as an incredible host for the preparation of magnetic nanoparticles. Biopolymer based magnetic nanocomposites have been fabricated from long time using method like co-precipitations, green synthesis, in-situ, hydrothermal and wet chemical method. Properties of biopolymer magnetic nanocomposites draw attention to the researchers towards fabricating at the nano level for various applications like as adsorptions inorganic metal, organic impurity, targeted drug-delivery, bio-sensing, catalysis activity, antimicrobial activity, antifungal activity, antioxidant activity, anti-cancer activity, energy, environmental remediation, waste water treatment and textiles. This review is designed to report very firstly reported biopolymer magnetic nanoparticles (BMNPs) in last ten years and attractive approach in various applications.

Mathematical modeling of the production of magnetic nanoparticles through counter-flow non-premixed combustion for biomedical applications

PurposeThe widespread usage of magnetic nanoparticles (MNPs) requires their efficient synthesis during combustion process. This study aims to present a mathematical model for the oxidation of MNPs in a counter-flow non-premixed combustion system to produce MNPs, where the key sub-processes during the oxidation reaction are involved.Design/methodology/approachTo accurately describe structure of flame and determine distributions of temperature and mass fractions of both reactants and products, equations of energy and mass conservations were solved based on the prevailing assumptions that three regions, i.e. preheating, reaction and oxidizer zones exist.FindingsThe numerical simulation was first validated against experimental data and characteristics of the combustion process are discussed. Eventually, the influences of crucial parameters such as reactant Lewis numbers, strain rate ratio, particle size, inert gas and thermophoretic force on structure of flame and combustion behavior were examined. The results show that maximum flame temperature can achieve 2,205 K. Replacing nitrogen with argon and helium as carrier gases can increase flame temperature by about 27% and 34%, respectively. Additionally, maximum absolute thermophoretic force was found at approximately 9.6 × 10–8 N.Originality/valueTo the best of authors’ knowledge, this is the first time to numerically model the preparation of MNPs in a counter-flow non-premixed combustion configuration, which can guide large-scale experimental work in a more effective way.

Catalytic Hydrogenation of Carbon Dioxide over Magnetic Nanoparticles: Modification in Fixed-Bed Reactor

A specific finger-projected fixed-bed reactor (FPFBR) was designed to efficiently utilize magnetic nanoparticles (MnFe2O4/Bi-MnFe2O4) for a model reaction (hydrogenation of a greenhouse gas, CO2, to valuable products: VPs). Coprecipitation method, with desired modification was used for the preparation of magnetic nanoparticles (MNPs) with controlled shape and size. Eighteen fingers in a single chamber were designed in the fixed-bed reactor’s skeleton; each finger worked as an independent reaction core. Controlled flow of hydrogen and CO2 was continuously provided to preheated reaction cores (catalyst beds) from saturator. One of the major products methanol {(%: Conv, 22/Sel 61)} among VPs was identified and quantified by GC. The efficiency of self-designed reactor was 74% for the direct catalytic hydrogenation of CO2 to valuable organic products.

Ultramicrotomy preparation of magnetic nanoparticles for transmission electron microscopy

Transmission electron microscopy (TEM) is one of the most important methods for the morphological characterization and structure analysis of nanomaterials. However, the characterization of magnetic materials has always been a challenge due to limitations arising from the design of electron microscopes. To tackle this problem, advanced sample preparation technology is needed, especially for magnetic materials. Here in this work ultrathin sectioning technology (ultramicrotomy) is used for the sample preparation of magnetic Fe3O4 nanoparticles embedded into a resin, where the loaded resin can be sliced into nanoscale sheets. By the optimization of the embedding method and the slicing process, nano-sheets with uniform thickness and exceptional flatness were prepared, where the nanoparticles exhibited uniform dispersion. It is shown that this technology also helps reducing the degree of pollution of the electron microscope by the magnetic nanoparticles under different electron beam irradiation intensities. Generally, the magnetic nanoparticles are more resistant to electron beam bombardment when embedded into a resin.

Study of doxorubicin release on apoferritin-magnetic-doxorubicin nanoparticle

Conjugation of nanoparticle with some substance can be a solution to a theragnostic of cancer cells. The release of doxorubicin from conjugated apoferritin-magnetic-doxorubicin (APO-NPM-DOX) was studied in different pH conditions and incubation time. The preparation of magnetic nanoparticle (Fe3O4) was done through the co-precipitation method using FeCl3 and FeCl2 (mol ratio 1:1) as the precursor. The encapsulation process was started by conjugation of magnetic nanoparticle with doxorubicin, then followed by incubation of the mixture in apoferritin solution for 2 hours in pH 3. The mixture was then set to pH 8 using NaOH and dialyzed in Tris-HCl. The doxorubicin release from APO-NPM-DOX was studied by incubation at 36.5 °C in different time variations in pH 5 and different pH conditions (4, 5, 6, 7) for a week. The doxorubicin release trend becomes steady after three days of incubation in pH 5 with 4.6% of the doxorubicin had been released. The highest percentage of doxorubicin release was found in pH 4, which is more than 1.2 times higher than in pH 5.

Polymer-Coated Magnetite Nanoparticles for Protein Immobilization.

Since their discovery, magnetic nanoparticles (MNPs) have become materials with great potential, especially considering the applications of biomedical sciences. A series of works on the preparation, characterization, and application of MNPs has shown that the biological activity of such materials depends on their size, shape, core, and shell nature. Some of the most commonly used MNPs are those based on a magnetite core. On the other hand, synthetic biopolymers are used as a protective surface coating for these nanoparticles. This review describes the advances in the field of polymer-coated MNPs for protein immobilization over the past decade. General methods of MNP preparation and protein immobilization are presented. The most extensive section of this article discusses the latest work on the use of polymer-coated MNPs for the physical and chemical immobilization of three types of proteins: enzymes, antibodies, and serum proteins. Where possible, the effectiveness of the immobilization and the activity and use of the immobilized protein are reported. Finally, the information available in the peer-reviewed literature and the application perspectives for the MNP-immobilized protein systems are summarized as well.

Preparation of magnetic nanoparticles by one step synthesis with morphology of particles changed based on time of reaction and temperature treatment

In present study, nanosized iron oxides particles are synthetised by easy one step precipitation from Mohric salt (NH4)2Fe(SO4)2·6H2O reacting with sodium hydroxide solution in temperature up to 60 °C. When changing the time of reaction, the iron oxide particles of different shape are prepared and when drying wet extracted particles at elevated temperature of 60 °C the change of 2D shaped morphology is observed. Depending on the time of reaction different ratios of FeOOH and Fe3O4 are obtained in this study. DTA – TGA, XRD, FTIR and SEM are used for the characterisation of particles in this study.

Preparation of magnetic nanoparticle integrated nanostructured lipid carriers for controlled delivery of ascorbyl palmitate

Most cancer treatments can cause vital side effects on healthy tissues. Ascorbic acid (AA) is a water-soluble antioxidant molecule and possesses a variety of functions such as prevention of tumor proliferation and treatment of cancer. However, AA, is very sensitive to air, heat and light. Its high hydrophilicity also makes the controlled delivery difficult. To overcome these problems, AA can be chemically-modified and made more hydrophobic by the esterification. Palmitic acid is one of the most common long-chain fatty acids that can be used for this purpose. It is known that Ascorbyl palmitate (AP) which is a lipopihilic derivative of AA, can inhibit cell proliferation and DNA synthesis in many types of cancer. Although AP has higher stability, its bioavailability and therapeutic effect is low due to its lipophilicity and low release capacity.•In this study, nanostructured lipid carriers (NLC) which are colloidal nanoparticles with high biocompatibility, low crystallinity and high hydrophobic-drug encapsulation capacity was prepared to increase the bioavailability of AP.•To provide triggered drug release via hyperthermia, magnetic nanoparticles (MNps) were integrated into the NLCs besides AP.•The synthesis of biocompatible NLCs with controlled and triggered release ability, is successfully completed and controlled release of AP as an antitumor agent is achieved.

Targeting kidneys by superparamagnetic allopurinol loaded chitosan coated nanoparticles for the treatment of hyperuricemic nephrolithiasis.

The major short coming of conventional therapy system is that they can't deliver the therapeutics specifically to a site within the body without producing nonspecific toxicity. Present research aimed at developing kidney targeted allopurinol (AP) loaded chitosan coated magnetic nanoparticles (A-MNPs) for the management of hyperuricemic nephropathy manifested in the form of nephrolithiasis. The work includes preparation of magnetic nanoparticles by chemical co-precipitation method and evaluation of the prepared batches for particle size analysis, Transmission electron microscopy, entrapment efficiency, in-vitro release study etc. Further, FTIR spectroscopy, X-ray diffraction, Differential Scanning Calorimetry, Vibrational sample magnetometer (VSM) and in-vivo animal studies were also performed. VSM analysis demonstrates that the prepared nanoparticles exhibit superparamagnetic magnetic behaviour which was retained even after coating by chitosan. In-vivo studies of A-MNPs showed 19.07-fold increase in kidney uptake of AP as compared to serum post 2h of administration in mice whereas no drug was detected in kidney and serum post 2h administration of pure drug (free-form) indicating successful targeting to kidney as well as sustained release of AP from the formulated A-MNPs. The significant (p < 0.01) effectiveness of A-MNPs in management of hyperuricemic nephrolithiasis was observed through estimating pH and uric acid levels in urine and serum samples of mice. These findings were also confirmed by histological examination of isolated kidney samples. Present investigation signifies that a simple external magnetic field is enough for targeting allopurinol to kidneys by formulating A-MNPs which further offers an effective approach for management of hyperuricemic nephrolithiasis. Graphical Abstract.

The High-Resolution Bitter Decoration Technique for the Magnetic Flux Structure Imaging at Low Temperatures

The high-resolution Bitter technique for visualization (decoration) of the magnetic-flux structure in superconductors and magnets at low temperatures is presented. This method is based on the preparation of magnetic nanoparticles directly during a low-temperature experiment (in situ) by evaporating a magnetic material in the atmosphere of a buffer gas (helium) above the sample surface. An apparatus was constructed and a technique was proposed to stabilize the temperature of a sample during decoration with an accuracy of ±1 K within a wide temperature range. As an example, the results of observation of the magnetic-flux structure in single crystals of BSCCO(2212) high-temperature superconductor and EuFe2(As0.79P0.21)2 ferromagnetic superconductor at T ≤ 18 K are presented.

From the Shelf to the Particle: Preparation of Highly Organic-Functionalized Magnetic Composites via 4-Nitrophenyl Reactive Ester.

Preparation of chemically tunable magnetic nanoparticles (MNPs) is of great interest in many technological fields. Although numerous methods have been developed to prepare MNPs coated with functional organic moieties, most of them are complex, multistep, and involve the preparation of a specific ligand to be inserted on the particle surface. Herein, we describe the preparation of MNPs covered with reactive polymer poly(4-nitrophenyl methacrylate). The composite was prepared by the dispersion polymerization of 4-nitrophenyl methacrylate in the presence of magnetite nanoparticles stabilized by oleic acid. The novel material can be easily modified with amines to give chemically stable amide bonds without installation of pH-dependent features in the link. The extent of particle modification is readily monitored by the release of 4-nitrophenol from the polymer using UV-vis spectrophotometry. Good agreement between the degree of functionalization assessed by colorimetry and elemental analysis was obtained, and functionalization up to 3 mmol g-1 is easily attained. To illustrate the applicability of the method for catalyst development, we prepared imidazole-covered MNPs that accelerate the hydrolysis of a model organophosphate, with rate constants approximately 105-fold higher than the spontaneous hydrolysis. The catalyst can be recovered by a magnet and recycled without appreciable loss of catalytic activity.

Polyamine-modified magnetic graphene oxide surface: Feasible adsorbent for removal of dyes

Magnetic nanoparticles were integrated with graphene oxide sheets modified by metformin to introduce poly-amine functionality in structure. Modified magnetic graphene oxide by metformin (MMGO) adsorption ability was studied for removal of methyl violet (MV) and acid red 88 (AR88) at different pH, initial concentration, and contact time. The successful preparation of magnetic nanoparticles supported with modified graphene oxide sheets is evident from FTIR spectra, TGA, zeta-potential and magnetic measurements. Morphology and chemical structure of the prepared MMGO nanocomposite was studied by TEM, SEM, XPS and EDS analyses. Surface area measurement of the MMGO composite revealed high BET surface area of 226 m2 g−1. Equilibrium isotherms were employed to evaluate the experimental data and calculate the isotherms' parameters. Results showed that adsorption process is based on Langmuir isotherm (R2 > 0.99) and adsorption capacity of fabricated nano-composite was found to be 243 mg g−1 for MV and 303 mg g−1 for AR88. Kinetical results were based on pseudo-second order (R2 > 0.99) and physisorption was main process in the rate-controlling step.