Activity Of Magnetic Nanoparticles Research Articles

Exploiting the Potential of Magnetic Nanoparticles for Rapid Diagnosis Tests (RDTs): Nanoparticle-Antibody Conjugates and Color Development Strategies.

Magnetic nanoparticles (MNPs) have emerged as a promising material in disease diagnostics due to their potential to enhance detection sensitivity, facilitate concentration and purification of target substances in diverse samples, and enable favorable color-based detection. In this study, antibody-conjugated MNPs were successfully synthesized and validated through two appropriate methods: the measurement of MNPs' size and the use of phosphatase methods. Additionally, three methods were suggested and implemented for developing color in MNPs-based immunoassay, including the formation of MNP aggregations, utilization of MNPs' peroxidase-like activity, and synthesis of dually-conjugated MNPs with both enzyme and antibody. In particular, color development utilizing nanoparticle aggregations was demonstrated to result in a more yellowish color as virus concentration increased, while the peroxidase activity of MNPs exhibited a proportional increase in color intensity as the MNP concentration increased. This observation suggests the potential applicability of quantitative analysis using these methods. Furthermore, effective concentration and purification of target substances were demonstrated through the collection of MNPs using an external magnetic field, irrespective of factors such as antibody conjugation, dispersion medium, or virus binding. Finally, based on the key findings of this study, a design proposal for MNPs-based immunoassay is presented. Overall, MNPs-based immunoassays hold significant potential for advancing disease diagnostics.

PEROXIDASE-LIKE ACTIVITY OF MAGNETIC NANOPARTICLES IN THE PRESENCE OF BLOOD PROTEINS

The generation of hydroxyl radicals from hydrogen peroxide in aqueous solutions containing magnetic nanoparticles (MNPs), hemoglobin (Hb), immunoglobulin G (IgG), and human serum albumin (HSA) has been determined. The dependence of the rate of formation of the oxidized product of o-phenylenediamine (o-PDA) on the concentration of MNPs in solution, as well as on the concentration of proteins, was obtained. The peroxidase-like activity of MNPs was shown to decrease in the presence of HSA and IgG, while the addition of Hb to the reaction mixture was leading to its decrease and increase depending on protein concentration. The obtained effects can be used in the development of systems based on MNPs for theranostics, in particular, for suppression of tumor growth, and in predicting the ability of particles to catalyze the generation of reactive oxygen species (ROS) in vivo.

Hyaluronic acid‐folic acid‐modified Fe3O4 magnetic nanocarriers for targeted delivery of piperine: Formation, characterization, and biological study

Biocompatibility targeted magnetic nanocarriers are a promising alternative to conventional chemotherapy. Herein, Fe3O4 magnetic nanoparticles (MNPs) functionalized hyaluronic acid (HA)‐folic acid (FA) was synthesized and piperine (PIP) loaded into MNPs. In vitro release analyses, antioxidant activity, hemolysis assay, and intrinsic cytotoxicity of MNPs were determined. The results revealed that the synthesized MNPs released higher amount of piperine in acidic ambience in comparison with neutral ambience. PIP‐loaded prepared MNPs exhibited higher antioxidant activity in comparison with the carrier. On the other hand, prepared Fe3O4 MNPs is hemocompatible. Also, the synthesized MNPs demonstrated the considerable antiproliferative effects in MCF‐7 cancer cells compared with fibroblast cells. The results suggest that Fe3O4‐NH‐HA‐FA MNPs as novel targeted delivery system can enhance the therapeutic effect of piperine.

Metal and Metal Oxides Nanoparticles and Nanosystems in Anticancer and Antiviral Theragnostic Agents.

The development of antiviral treatment and anticancer theragnostic agents in recent decades has been associated with nanotechnologies, and primarily with inorganic nanoparticles (INPs) of metal and metal oxides. The large specific surface area and its high activity make it easy to functionalize INPs with various coatings (to increase their stability and reduce toxicity), specific agents (allowing retention of INPs in the affected organ or tissue), and drug molecules (for antitumor and antiviral therapy). The ability of magnetic nanoparticles (MNPs) of iron oxides and ferrites to enhance proton relaxation in specific tissues and serve as magnetic resonance imaging contrast agents is one of the most promising applications of nanomedicine. Activation of MNPs during hyperthermia by an external alternating magnetic field is a promising method for targeted cancer therapy. As therapeutic tools, INPs are promising carriers for targeted delivery of pharmaceuticals (either anticancer or antiviral) via magnetic drug targeting (in case of MNPs), passive or active (by attaching high affinity ligands) targeting. The plasmonic properties of Au nanoparticles (NPs) and their application for plasmonic photothermal and photodynamic therapies have been extensively explored recently in tumor treatment. The Ag NPs alone and in combination with antiviral medicines reveal new possibilities in antiviral therapy. The prospects and possibilities of INPs in relation to magnetic hyperthermia, plasmonic photothermal and photodynamic therapies, magnetic resonance imaging, targeted delivery in the framework of antitumor theragnostic and antiviral therapy are presented in this review.

Demulsification Performance and Mechanism of Tertiary Amine Polymer-Grafted Magnetic Nanoparticles in Surfactant-Free Oil-in-Water Emulsion.

Numerous cationic magnetic nanoparticles (MNPs) have previously been developed for demulsifying oil-in-water (O/W) emulsion, and results showed that the cationic MNPs could effectively flocculate and remove the negatively charged oil droplets via charge attraction; however, to the best of our knowledge, there are no research reports regarding the synergetic influence of both the positive charge density and interfacial activity of MNPs on the demulsification performance. In this study, three tertiary amine polymer-grafted MNPs, namely, poly(2-dimethylaminoethyl acrylate)-grafted MNPs (M-PDMAEA), poly(2-dimethylamino)ethyl methacrylate)-grafted MNPs (M-PDMAEMA), and poly(2-diethylaminoethyl methacrylate)-grafted MNPs (M-PDEAEMA), were synthesized and evaluated for their demulsification performance. Results demonstrated that a high positive charge density and superior interfacial activity of MNPs could cause partial oil droplet re-dispersion when excessive MNPs were introduced, leading to a lower magnetic separation efficiency and narrower demulsification window. Herein, a demulsification window is defined as a range of nanoparticle dosages in which the MNPs can effectively demulsify the O/W emulsion under certain conditions. For highly positively charged MNPs, their good interfacial activity could aggravate the formation of a narrower demulsification window. When tertiary amine polymer-grafted MNPs carried a lower positive charge density or weak interfacial activity, that is, M-PDMAEA at pH 4.0, M-PDMAEMA at pH 5.0-9.0, and M-PDEAEMA at pH 9.0-10.0, wide demulsification windows were observed. Additionally, a recycling experiment suggested that MNPs could maintain high demulsification efficiency up to at least five cycles, indicating their satisfactory recyclability. The three tertiary amine polymer-grafted MNPs can be potentially used for efficient demulsification from surfactant-free O/W emulsion in various pH ranges.

Development of magnetically recyclable nanocatalyst for enhanced Fenton and photo-Fenton degradation of MB and Cr(VI) photo-reduction

The present work reports the facile green synthesis of Fe3O4 magnetic nanoparticles (MNPs) and their Fenton and photo-Fenton catalytic activity for reduction reactions. The glucose-mediated MNPs exhibit spherical morphology with an average diameter of 6.3 ± 1.1 nm. The catalytic activity of MNPs evaluated for Fenton and the photo-Fenton reactions resulted in 92 and 93% dye degradation in just 120 and 75 min, respectively. The magnificence of this novel synthesis methodology is the higher efficiency of both processes at varied pH ranges. Different catalytic parameters like wide pH range, catalyst dose, and H2O2 concentrations have made it more effective for both processes. Besides, the reusability study showed 63.71 and 57.57% activity even after six cycles in Fenton and photo-Fenton processes, respectively. The scavenger study showed the involvement of •OHads over •OHfree in the Fenton process, where •OH was found as a prime source of dye degradation in the photo-Fenton process. Moreover, Fe3O4 MNPs successfully reduced the 80 ppm load of Cr(VI) within 25 min, which improved further to 15 min by adding a chelating agent. This Fenton and photo-Fenton magnetically reusable catalyst will indulge the development of water treatment in an eco-friendly and economical way with great potential.

Biological Impact of γ-Fe2O3 Magnetic Nanoparticles Obtained by Laser Target Evaporation: Focus on Magnetic Biosensor Applications.

The biological activity of γ-Fe2O3 magnetic nanoparticles (MNPs), obtained by the laser target evaporation technique, was studied, with a focus on their possible use in biosensor applications. The biological effect of the MNPs was investigated in vitro on the primary cultures of human dermal fibroblasts. The effects of the MNPs contained in culture medium or MNPs already uptaken by cells were evaluated for the cases of the fibroblast’s proliferation and secretion of cytokines and collagen. For the tests related to the contribution of the constant magnetic field to the biological activity of MNPs, a magnetic system for the creation of the external magnetic field (having no commercial analogues) was designed, calibrated, and used. It was adapted to the size of standard 24-well cell culture plates. At low concentrations of MNPs, uptake by fibroblasts had stimulated their proliferation. Extracellular MNPs stimulated the release of pro-inflammatory cytokines (Interleukin-6 (IL-6) and Interleukin-8 (IL-8) or chemokine (C-X-C motif) ligand 8 (CXCL8)) in a concentration-dependent manner. However, the presence of MNPs did not increase the collagen secretion. The exposure to the uniform constant magnetic field (H ≈ 630 or 320 Oe), oriented in the plane of the well, did not cause considerable changes in fibroblasts proliferation and secretion, regardless of presence of MNPs. Statistically significant differences were detected only in the levels of IL-8/CXCL8 release.

Recent Developments in Innovative Magnetic Nanoparticles-Based Immunoassays: From Improvement of Conventional Immunoassays to Diagnosis of COVID-19.

During the ongoing COVID-19 pandemic, the development of point-of-care (POC) detection with high sensitivity and rapid detection time is urgently needed to prevent transmission of infectious diseases. Magnetic nanoparticles (MNPs) have been considered attractive materials for enhancing sensitivity and reducing the detection time of conventional immunoassays due to their unique properties including magnetic behavior, high surface area, excellent stability, and easy biocompatibility. In addition, detecting target analytes through color development is necessary for user-friendly POC detection. In this review, recent advances in different types of MNPs-based immunoassays such as improvement of the conventional enzyme-linked immunosorbent assay (ELISA), immunoassays based on the peroxidase-like activity of MNPs and based on the dually labeled MNPs, filtration method, and lateral-flow immunoassay are described and we analyze the advantages and strategies of each method. Furthermore, immunoassays incorporating MNPs for COVID-19 diagnosis through color development are also introduced, demonstrating that MNPs can become common tools for on-site diagnosis.

Progress and prospects of magnetic iron oxide nanoparticles in biomedical applications: A review.

Nanoscience has been considered as one of the most substantial research in modern science. The utilization of nanoparticle (NP) materials provides numerous advantages in biomedical applications due to their unique properties. Among various types of nanoparticles, the magnetic nanoparticles (MNPs) of iron oxide possess intrinsic features, which have been efficiently exploited for biomedical purposes including drug delivery, magnetic resonance imaging, Magnetic-activated cell sorting, nanobiosensors, hyperthermia, and tissue engineering and regenerative medicine. The size and shape of nanostructures are the main factors affecting the physicochemical features of superparamagnetic iron oxide nanoparticles, which play an important role in the improvement of MNP properties, and can be controlled by appropriate synthesis strategies. On the other hand, the proper modification and functionalization of the surface of iron oxide nanoparticles have significant effects on the improvement of physicochemical and mechanical features, biocompatibility, stability, and surface activity of MNPs. This review focuses on popular methods of fabrication, beneficial surface coatings with regard to the main required features for their biomedical use, as well as new applications.

Poly(catechol) modified Fe3O4 magnetic nanocomposites with continuous high Fenton activity for organic degradation at neutral pH.

Fe3O4 magnetic nanoparticles (MNPs) have been widely used as a recyclable catalyst in Fenton reaction for organic degradation. However, the pristine MNPs suffer from the drawbacks of iron leaching in acidic conditions as well as the decreasing catalytic activity of organic degradation at a pH higher than 3.0. To solve the problems, Fe3O4 MNPs were modified by poly(catechol) (Fe3O4/PCC MNPs) using a facile chemical co-precipitation method. The poly(catechol) modification improved both the dispersity and the surface negative charges of Fe3O4/PCC MNPs, which are beneficial to the catalytic activity of MNPs for organic degradation. Moreover, the poly(catechol) modification enhanced the efficiency of Fe(II) regeneration during Fenton reaction due to the acceleration of Fe(III) reduction by the phenolic/quinonoid redox pair. As a result, the Fenton reaction with Fe3O4/PCC MNPs could efficiently degrade organic molecules, exampled by methylene blue (MB), in an expanded pH range between 3.0 and 10.0. In addition, Fe3O4/PCC MNPs could be reused up to 8 cycles for the MB degradation with negligible iron leaching of lower than 1.5 mg L-1. This study demonstrated Fe3O4/PCC MNPs are a promising heterogeneous Fenton catalysts for organic degradation.

Fundamentals to Apply Magnetic Nanoparticles for Hyperthermia Therapy.

The activation of magnetic nanoparticles in hyperthermia treatment by an external alternating magnetic field is a promising technique for targeted cancer therapy. The external alternating magnetic field generates heat in the tumor area, which is utilized to kill cancerous cells. Depending on the tumor type and site to be targeted, various types of magnetic nanoparticles, with variable coating materials of different shape and surface charge, have been developed. The tunable physical and chemical properties of magnetic nanoparticles enhance their heating efficiency. Moreover, heating efficiency is directly related with the product values of the applied magnetic field and frequency. Protein corona formation is another important parameter affecting the heating efficiency of MNPs in magnetic hyperthermia. This review provides the basics of magnetic hyperthermia, mechanisms of heat losses, thermal doses for hyperthermia therapy, and strategies to improve heating efficiency. The purpose of this review is to build a bridge between the synthesis/coating of magnetic nanoparticles and their practical application in magnetic hyperthermia.

Electrochemical performance of magnetic nanoparticle-decorated reduced graphene oxide (MRGO) in various aqueous electrolyte solutions

The objective of this work is twofold: (1) to improve the electrochemical performance of reduced graphene oxide (RGO) by decorating RGO sheets with magnetic nanoparticles (MNPs) and (2) to evaluate the electrochemical performance of RGO and MNP-decorated RGO (MRGO) in various aqueous electrolyte solutions (phosphate buffer solution (PBS) containing ferricyanide, PBS containing ferricyanide and KCl, Na2SO4, and KOH). The morphological and structural characteristics of solvothermal synthesized RGO and MRGO revealed the decoration of phase pure Fe3O4 nanoparticles on RGO sheets. In FC-PBS-KCl electrolyte solution, MRGO showed higher redox peak current (83.89 μA) and lower peak potential separation (0.11 V) at 50 mV s−1 scan rate compared with that in FC-PBS electrolyte solution. MRGO showed 15.5% higher peak current than that for the RGO in FC-PBS-KCl electrolyte solution. Moreover, the peak current for MRGO in FC-PBS-KCl was increased by 30% when compared with that in FC-PBS electrolyte solution. These results suggest that MRGO in FC-PBS-KCl electrolyte solution can be a good electron pathway between electrode and electrolyte solution for sensing applications. On the other hand, in both Na2SO4 and KOH electrolyte solution, RGO and MRGO showed supercapacitive behavior. In KOH, MRGO exhibited higher specific capacitance (180 Fg−1 at 3 A g−1) and superior cyclic stability (87% after 2000 cycles) compared with that in Na2SO4. MRGO showed 219% increase in specific capacitance than that of the RGO in KOH electrolyte solution. The superior electrochemical performance of MRGO compared with that of RGO is attributed to the synergistic effect of conductivity of RGO and redox activity of MNPs.

Kinetic Studies on the Catalytic Degradation of Rhodamine B by Hydrogen Peroxide: Effect of Surfactant Coated and Non-Coated Iron (III) Oxide Nanoparticles.

Iron (III) oxide (Fe3O4) and sodium dodecyl sulfate (SDS) coated iron (III) oxide (SDS@Fe3O4) nanoparticles (NPs) were synthesized by the co-precipitation method for application in the catalytic degradation of Rhodamine B (RB) dye. The synthesized NPs were characterized using X-ray diffractometer (XRD), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infra-red (FT-IR) spectroscopy techniques and tested in the removal of RB. A kinetic study on RB degradation by hydrogen peroxide (H2O2) was carried out and the influence of Fe3O4 and SDS@Fe3O4 magnetic NPs on the degradation rate was assessed. The activity of magnetic NPs, viz. Fe3O4 and SDS@Fe3O4, in the degradation of RB was spectrophotometrically studied and found effective in the removal of RB dye from water. The rate of RB degradation was found linearly dependent upon H2O2 concentration and within 5.0 × 10−2 to 4.0 × 10−1 M H2O2, the observed pseudo-first-order kinetic rates (kobs, s−1) for the degradation of RB (10 mg L−1) at pH 3 and temperature 25 ± 2 °C were between 0.4 and 1.7 × 104 s−1, while in presence of 0.1% w/v Fe3O4 or SDS@Fe3O4 NPs, kobs were between 1.3 and 2.8 × 104 s−1 and between 2.6 and 4.8 × 104 s−1, respectively. Furthermore, in presence of Fe3O4 or SDS@Fe3O4, kobs increased with NPs dosage and showed a peaked pH behavior with a maximum at pH 3. The magnitude of thermodynamic parameters Ea and ΔH for RB degradation in presence of SDS@Fe3O4 were 15.63 kJ mol−1 and 13.01 kJ mol−1, respectively, lowest among the used catalysts, confirming its effectiveness during degradation. Furthermore, SDS in the presence of Fe3O4 NPs and H2O2 remarkably enhanced the rate of RB degradation.

Poly-γ-Glutamic Acid/Chitosan Hydrogel Nanoparticles Entrapping Glucose Oxidase and Magnetic Nanoparticles for Glucose Biosensing.

We have developed hydrogel nanoparticles made of poly-γ-glutamic acid (PGA) and chitosan, which entraps both glucose oxidase (GOx) and magnetic nanoparticles (MNPs) within the hydrogel matrix. The preparation of poly-γ-glutamic acid/chitosan hydrogel nanoparticles (PGA/CS NPs) entrapping GOx and MNPs begins with the mixing of GOx and MNPs with PGA solution followed by their dropwise addition into chitosan solution to induce rapid ionic gelation. The glucose sensing relies on the generation of H2O2 through the entrapped GOx-mediated catalysis in the presence of glucose, which consequently activates the peroxidase-like activity of MNPs to convert an employed chromogenic substrate, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), into a green colored product. Using this strategy, the target glucose was successfully detected over a wide linear range, from 5 to 100 μM with a lower detection limit of 3 μM, which is sufficient to diagnose high level of glucose (hyperglycemia) in human blood. The hydrogel nanoparticle-based glucose biosensor also showed high stability with magnetic reusability. Since any oxidative enzymes could be incorporated within the PGA/CS NPs, we expect that the hydrogelbased biosensor would be highly beneficial for the detection of various other clinically important target molecules.

Chlorpyrifos degradation efficiency of Bacillus sp. laccase immobilized on iron magnetic nanoparticles.

The present study explored the immobilization of laccase onto iron magnetic nanoparticles (MNPs) to enhance its enzymatic properties and applications. The immobilization process was optimized using Box-Behnken design (BBD). BBD showed significance towards the quadratic model with experimental data. Maximum laccase activity recovery (99%) of the predicted model was observed at 0.75mg/mL of laccase concentration, 200mg/mL of MNPs, 0.3% cross linking with carbodiimide, and 3h of cross-linking time. The magnetization activity of MNPs (8emu/g) and the immobilized laccase with MNPs (4emu/g) was analyzed using vibrating sample magnetometer (VSM). Maximum activity of immobilized laccase was observed at pH 7.0 and 55°C. The immobilized laccase has greater stability (100h) and significant chlorpyrifos (pesticide) degradation activity. High-performance liquid chromatography (HPLC) results confirmed the degraded metabolic products of chlorpyrifos. In all, the immobilized laccase was superior to free laccase, showing promising structural and application characteristics.

In Situ Generation of Prussian Blue with Potassium Ferrocyanide to Improve the Sensitivity of Chemiluminescence Immunoassay Using Magnetic Nanoparticles as Label.

Using magnetic nanoparticles (MNPs) as a label in immunoassay (IA) possesses advantages such as high specific surface area, simple modification process. However, the catalytic activity of MNPs is low, which limits their applications in IA. The present study found it interesting that potassium ferrocyanide reacts with MNPs, leading to the in situ generation of Prussian blue. The produced Prussian blue shows high catalytic activity on a luminol chemiluminescent (CL) reaction. Therefore, a simple and sensitive immunoassay for rabbit IgG (rIgG) as model analyte using MNPs as label was developed. The CL intensity had a linear increase with the concentration of rIgG that ranged from 0.625 to 20 ng mL-1. The limit of detection was calculated to be 0.59 ng mL-1. In addition, the applicability of this method was evaluated using the standard addition method. The recovery ranged from 80.0% to 115.0%. What's more, the proposed CLIA method based on in situ generation of Prussian blue with MNPs was also applied to the detection of carcinoembryonic antigen (CEA) and hepatitis B virus (HBV)-related sequence-specific DNA. The LOD for the detection of CEA and sequence-specific DNA was estimated to be 0.28 ng mL-1 and 0.044 pmol, respectively.

Colorimetric Detection of MPT64 Antibody Based on an Aptamer Adsorbed Magnetic Nanoparticles for Diagnosis of Tuberculosis.

We have developed a colorimetric biosensing system for the detection of antibody against MPT64, a protein secreted by Mycobacterium tuberculosis, using aptamer DNA adsorbed Fe₃O₄ magnetic nanoparticles (MNPs) for diagnosis of tuberculosis (TB). In this system, MNPs were first incubated with single stranded (ss) DNA-type aptamer having a high affinity toward target antibody against MPT64 (anti-MPT64), resulting in quick inhibition of the peroxidase-like activity of MNPs via the adsorption of aptamer on the surface of MNPs. By the addition of sample solutions containing anti-MPT64, aptamer bound on the surface of MNPs would strongly interact with free anti-MPT64 and be detached from the MNPs, thereby increasing the available surface area of the MNPs and consequently yielding enhanced peroxidase activity. Using this strategy, target anti-MPT64 was successfully detected by displaying increased colorimetric intensities from the higher oxidation of employed peroxidase substrate, 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) (ABTS). Based on these results, we anticipate that aptamer adsorbed MNPs can serve as a potent probe system for the detection of clinically important target molecules.

A universal one-pot assay strategy based on bio-inorganic cascade catalysts for different analytes by changing pH-dependent activity of enzymes on enzyme mimics

In general, peroxidase mimics show optimal activity at acidic pH, while many enzymes work at physiological pH. To realize one-pot colorimetric detection based on enzyme-nanozyme-coupled system, the usual strategy is to change the pH-dependent activity of nanozymes, which is difficult for most of nanozymes. Unlike common strategies, we changed the pH-dependent activity of enzymes rather than nanozymes. First, we facilely synthesized Co3O4 magnetic peroxidase mimics with uniform size, good dispersibility and superparamagnetism by using protein as templates at mild condition. The as-prepared Co3O4 magnetic nanoparticles (MNPs) were covered with the layers of protein, facilitating the further functionalization with enzymes. Exhilaratingly, we discovered that the immobilization on Co3O4 MNPs could regulated pH-dependent activity of enzymes, such as glucose oxidase (GOx) and glucoamylase (GA). Based on the overlapped pH range between peroxidase-like activity of Co3O4 MNPs and catalytic activity of GOx, the hybrid cascade catalysts were employed for a one-pot glucose detection, exhibiting wide detection range and good selectivity. Furthermore, GA and GOx were co-mobilized on Co3O4 MNPs to realize the one-pot colorimetric starch detection, confirming the universality of the proposed strategy. As an additional bonus, hybrid cascade catalysts could be expediently separated from the reaction solution under the magnetic field in order to rapidly terminate the reaction and recycle enzymes. This work would open an avenue for the various one-pot enzyme-nanozyme-coupled assay.

Comparative evaluation of magnetic hyperthermia performance and biocompatibility of magnetite and novel Fe-doped hardystonite nanoparticles for potential bone cancer therapy

Hyperthermia—increasing temperature of cancerous tissue for a short period of time—is considered as an effective treatment for various cancer types such as malignant bone tumors. Superparamagnetic and ferromagnetic particles have been studied for their hyperthermic properties in treating various types of cancers. The activation of magnetic nanoparticles by an alternating magnetic field is currently being explored as a technique for targeted therapeutic heating of different tumors and is being studied as an adjuvant to conventional chemotherapy and radiation therapy. In the case of bone cancers, to increase the efficiency of treatment in the hyperthermia therapy, employed materials should support bone regeneration as well. Magnetite is one of the most attractive magnetic nanoceramics used in hyperthermia application. However, biocompatibility and bioactivity of this material have raised questions. There is a high demand for extremely efficient hyperthermia materials which are equally biocompatible to non-tumor cells and tissues. We report the development of a biocompatible and bioactive material with desirable magnetic properties that show excellent hyperthermia properties and can be used for destruction of the cancerous tissue in addition to supporting tissue regeneration for treatment of bone tumors. In the current study, iron (Fe3+)-containing HT nanostructured material was prepared, and its biocompatibility, bioactivity, and hyperthermia abilities were studied. The developed materials showed effective hyperthermic properties with increased biocompatibility as compared to magnetite.

Magnetic nanocrystallites strontium hexaferrite as an efficient catalyst in the green Betti reaction

The sol–gel auto-combustion method was applied for preparation of SrFe12O19 magnetic nanoparticles (MNPs). Then, the prepared SrFe12O19 was analyzed by VSM, FT-IR, SEM, N2 adsorption-desorption and XRD pattern. According to the hysteresis loops of SrFe12O19 MNPs, its magnetic saturation was about 79 emu/g and also it is a typical feature of ferromagnetic compound. SEM image showed semi-spherical particles with average size of 70 nm. The BET surface area of SrFe12O19 MNPs was 10.4 m2/g. Moreover, the catalytic activity of SrFe12O19 MNPs was tested for the first time toward the Betti reaction. The results showed that it is an efficient catalyst which can be easily separated from the reaction mixture using an external magnet and gives the pure products in high yields within short reaction time.