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Magnetite nanoparticles (Fe3O4 NPs) have garnered significant attention over the past twenty years, primarily due to their superparamagnetic properties. These properties allow the NPs to respond to external magnetic fields, making them particularly useful in various technological applications. One of the most fascinating aspects of Fe3O4 NPs is their ability to self-assemble into complex structures. Research over this period has focused heavily on how these nanoparticles can be organized into a variety of superstructures, classified by their dimensionality—namely one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) configurations. Despite a wealth of studies, the literature lacks a systematic review that synthesizes these findings. This review aims to fill that gap by providing a thorough overview of the recent progress made in the fabrication and organization of Fe3O4 NP assemblies via a bottom-up self-assembly approach. This methodology enables the controlled construction of assemblies at the nanoscale, which can lead to distinctive functionalities compared to their individual counterparts. Furthermore, the review explores the diverse applications stemming from these nanoparticle assemblies, particularly emphasizing their contributions to important areas such as imaging, drug delivery, and the diagnosis and treatment of cancer. [ABSTRACT FROM AUTHOR]

A novel optical lactate biosensor is presented that utilizes a colorimetric interaction between H2O2 liberated by a binary enzymatic reaction and bis(neocuproine)copper(II) complex ([Cu(Nc)2]2+) known as CUPRAC (cupric reducing antioxidant capacity) reagent. In the first step, lactate oxidase (LOx) and pyruvate oxidase (POx) were separately immobilized on silanized magnetite nanoparticles (SiO2@Fe3O4 NPs), and thus, 2 mol of H2O2 was released per 1 mol of the substrate due to a sequential enzymatic reaction of the mixture of LOx-SiO2@Fe3O4 and POx-SiO2@Fe3O4 NPs with lactate and pyruvate, respectively. In the second step, the absorbance at 450 nm of the yellow-orange [Cu(Nc)2]+ complex formed through the color reaction of enzymatically produced H2O2 with [Cu(Nc)2]2+ was recorded. The results indicate that the developed colorimetric binary enzymatic biosensor exhibits a broad linear range of response between 0.5 and 50.0 µM for lactate under optimal conditions with a detection limit of 0.17 µM. The fabricated biosensor did not respond to other saccharides, while the positive interferences of certain reducing compounds such as dopamine, ascorbic acid, and uric acid were minimized through their oxidative removal with a pre-oxidant (NaBiO3) before enzymatic and colorimetric reactions. The fabricated optical biosensor was applied to various samples such as artificial blood, artificial/real sweat, and cow milk. The high recovery values (close to 100%) achieved for lactate-spiked samples indicate an acceptable accuracy of this colorimetric biosensor in the determination of lactate in real samples. Due to the increase in H2O2 production with the bienzymatic lactate sensor, the proposed method displays double-fold sensitivity relative to monoenzymatic biosensors and involves a neat color reaction with cupric-neocuproine having a clear stoichiometry as opposed to the rather indefinite stoichiometry of analogous redox dye methods. [ABSTRACT FROM AUTHOR]

This study compares magnetite (Fe3O4) nanoparticles synthesized using Aspergillus elegans extract versus commercially available magnetite nanoparticles, focusing on their efficacy in dye degradation. The biosynthesis of Fe3O4 nanoparticles using fungal extracts offers a sustainable and eco-friendly alternative to conventional chemical methods. The nanoparticles were characterized using various techniques, including UV–Vis spectroscopy, XRD, FTIR, SEM, TEM, DLS, zeta potential, and VSM analysis, to assess their structural, morphological, and magnetic properties. Results showed that fungus-mediated Fe3O4 nanoparticles were smaller, with an average size of 19.2 nm, and exhibited better crystallinity, surface functionalization, and colloidal stability than their commercial counterparts, which had an average size of 60 nm. Additionally, the fungal nanoparticles displayed superior magnetic properties with a saturation magnetization of 50 emu/g compared to 36 emu/g for commercial Fe3O4. The dye degradation potential of the nanoparticles was tested using methyl violet, methyl orange, and rose bengal dyes. Fungus-mediated Fe3O4 nanoparticles demonstrated higher dye removal efficiency than commercial Fe3O4, indicating enhanced catalytic activity due to their smaller size and larger surface area. This study highlights the potential of myco-synthesized Fe3O4 nanoparticles as effective agents for environmental remediation, particularly in removing of hazardous synthetic dyes from wastewater.

Nonylphenol is an aromatic organic compound that has an estrogen-like effect and has a negative effect on the human endocrine system. A method has been developed for the competitive determination of nonylphenol using magnetic particles, rabbit antiserum, nonylphenol conjugate with soybean trypsin inhibitor (STI) and biotin. The principle of the analysis is the formation of immune complexes on the surface of magnetite particles due to covalent immobilization of protein G through the oriented immobilization of polyclonal antibodies from rabbit serum during a competitive reaction between the free analyte (nonylphenol) and the bound one (as part of the nonylphenol-STI-biotin conjugate) for the binding sites of specific antibodies. The detection of formed immune complexes is proposed to be carried out using a streptavidin-polyperoxidase conjugate, which makes it possible to achieve a nine-fold gain in the level of the analytical signal. The developed ELISA using magnetite particles allows us to achieve a detection limit of nonylphenol at the level of 3.8 ng/mL, which is 14.5 times lower in comparison with the classic competitive ELISA (55 ng/mL). Based on the results of the experimental work, the optimized volume of the test sample was 500 μL, which makes it possible to concentrate low-contaminated samples by 17 times. [ABSTRACT FROM AUTHOR]

Nanoparticle size effects on elastic properties of polymeric bio-nanocomposites were studied using atomistic molecular dynamics (MD) simulations. Spherical magnetite nanoparticles (MNPs) were placed at the centre of amorphous polypyrrole (PPy) polymer in three models with different sizes. Three models of nanocomposites with the same particle volume fractions with different sizes were considered. The Lennard-Jones 6-12 potential modelled the interface interaction between polymer and particles. Initially, the obtained mechanical properties for pristine PPy and magnetite in the bulk state showed an acceptable agreement with experimental data. Subsequently, simulation results illustrated that incorporating MNP into the PPy matrix improves the elastic modulus of the matrix by 28-58%, and more importantly, decreasing the size of the nanoparticle from 2.40 to 1.80 nm in the system leads to increasing Young's modulus of the nanocomposite from a 3.20 to 3.94 GPa. Furthermore, the atomic investigation demonstrated that this change in elastic modulus is due to the change in interatomic interaction between nanoparticle and polymer when the nanoparticle size changes. Finally, the comparison between the results of MD and micromechanical analysis shows that as the size of the nanoparticle in nanocomposites increases, the elastic properties of nanocomposites converge with the results obtained by the micromechanical approach. [ABSTRACT FROM AUTHOR]

We present the synthesis of acrylic-resin-based tubular micromotors incorporating layers of magnetite nanoparticles (MNPs) and catalase (Cat) on the inner pore surface (Cat tube micromotors) and investigate their distinctive self-propulsion capabilities modulated by visible light irradiation. In an aqueous H2O2 solution, the Cat tubes demonstrate autonomous movement by expelling O2 bubbles from their opening ends. The propulsion velocity reaches its maximum at the optimal pH and temperature for the Cat enzyme activity. Remarkably, the swimming velocity undergoes rapid acceleration upon exposure to visible light and promptly decelerates upon the cessation of illumination. This phenomenon is ascribed to the photothermal effect induced by the MNPs, elevating the temperature of the adjacent Cat layer and thereby enhancing enzyme activity. The micromotors exhibit recurrent acceleration and deceleration in response to on/off light irradiation, showcasing a high degree of sensitivity and responsiveness. [ABSTRACT FROM AUTHOR]

A facile, one-pot, rapid and cost-effective green synthesis approach is adopted for synthesis of spherical magnetite nanoparticles (Fe3O4) using Averrhoa carambola leaf extract for removal of Cr(VI). The polar biomolecules of leaf extract act as non-toxic surfactants and as reducing as well as stabilizing agents. The morphological, structural and optical properties of bio-based magnetite nanoparticles were characterized by FESEM, XRD, FT-IR, UV–VIS DRS and Raman analysis. The batch biosorption of Cr(VI) was investigated at different experimental limits such as contact time, temperature, pH, adsorbent dose and metal concentration. The experimental data was well fitted to Langmuir adsorption isotherm and found to follow linear pseudo-second-order kinetics. The maximum biosorption efficiency of bio-based magnetite nanoparticles was recorded 99.34% and can be reused proficiently upto 7 cycles. The mechanism for role of biomolecules in synthesis of nanoparticles along with the mechanism for biosorption of Cr(VI) over bio-based magnetite nanoparticles were discussed. The bio-based magnetite nanoparticles can be effectively used for removal of Cr(VI) from groundwater in contaminated areas. [ABSTRACT FROM AUTHOR]

Transmission spectra of colloidal solutions of magnetite nanoparticles in kerosene with various volume concentrations of the solid phase and the influence on them of an external magnetic field have been studied. A pronounced maximum in the near-IR region at 740–760 nm appeared in the spectra as the magnetite concentration increased. The magnetite concentration limits at which the transmission spectra were successfully described by the Bouguer–Lambert law were established. The appearance of a maximum in the transmission spectra with increasing concentration was shown to be associated with a minimum in the spectrum of the imaginary part of the refractive index of nanosized magnetite. [ABSTRACT FROM AUTHOR]

The main objective of this study is to investigate the efficiency of coagulation-flocculation process for surface water treatment, using the conventional coagulants (ferric chloride (FeCl3) and polyferric sulphate (PFS)), magnetic nanoparticles (MNPs), Fe-based metal-organic framework MIL-53(Fe), magnetic metal organic framework (MMOF), and evaluate the effect of combination of these coagulants on the coagulation process. MNPs were synthesized using the co-precipitation method and MIL-53(Fe) was synthesized using solvothermal process. The synthesized coagulants were characterized using point of zero charge (pHpzc), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) and Brunauer–Emmett–Teller (BET) techniques. The point zero of charge pH (pHPZC) values for the prepared MNPs, MIL-53(Fe) and MMOF were for found to be 7.8, 5.0 and 3.0, respectively, while the respective surface area for MIL-53(Fe) and MMOF were 23.8 and 11.8 m2/g. In addition, pore sized MMOF was found to be 59.455 Å which is larger than that for MIL-53(Fe) (34.705 Å). The results obtained from this study revealed that turbidity removal exceeded 98 % when using 30 mg/L of FeCl3 at pH 7. The same removal efficiency required less dose of PFS (10 mg/L) at a pH 8.5. The combination of MNPs with FeCl3 enhanced the removal efficiency to more than 99 % at the optimized condition of FeCl3. However, using MIL-53(Fe) slightly enhanced the FeCl3 coagulation at low dosage (10 mg/L) at pH 7, whereas, MMOF recorded better enhancement for the FeCl3 coagulation at the same conditions, reaching up to 98 %. Moreover, the combination of PFS and MNPs provided the best coagulation performance with turbidity removal of more than 99 % at low dose and at pH 7.

Magnetite nanoparticles (Fe3O4 NPs) have garnered significant attention over the past twenty years, primarily due to their superparamagnetic properties. These properties allow the NPs to respond to external magnetic fields, making them particularly useful in various technological applications. One of the most fascinating aspects of Fe3O4 NPs is their ability to self-assemble into complex structures. Research over this period has focused heavily on how these nanoparticles can be organized into a variety of superstructures, classified by their dimensionality—namely one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) configurations. Despite a wealth of studies, the literature lacks a systematic review that synthesizes these findings. This review aims to fill that gap by providing a thorough overview of the recent progress made in the fabrication and organization of Fe3O4 NP assemblies via a bottom-up self-assembly approach. This methodology enables the controlled construction of assemblies at the nanoscale, which can lead to distinctive functionalities compared to their individual counterparts. Furthermore, the review explores the diverse applications stemming from these nanoparticle assemblies, particularly emphasizing their contributions to important areas such as imaging, drug delivery, and the diagnosis and treatment of cancer.

Among nanoparticles (NPs) of metal oxides, magnetite NPs are the most well-known. The need for regulations related to the safety of magnetite NPs requires a deep understanding of their toxicological paradigm. The purpose of the presented review is to analyze the methods of studying the magnetite NPs toxicity and to summarize their toxicity factors based on the literature data. Literature sources were searched in the PubMed database, and 99 works were selected, supplemented with articles from other databases in some cases. It is shown that the study of the magnetite NPs toxicity became widespread during the last decade, reflecting the expansion of the list of synthesized magnetic NPs and the awareness that the prospects for their use depend on the safety of the created nanomaterial. The safety assessment of magnetite NPs on cell lines is the most popular. Primitive and more highly organized animals can be used to evaluate various aspects of the magnetite NPs toxicity. The toxicity factors of magnetite NPs depend on their characteristics (core composition, coating, size, and shape) and the mode of application (concentration, dose, exposure, type of cells, or animal model). One of the main mechanisms of nanomagnetite toxicity is the interference with iron metabolism and increased generation of reactive oxygen species leading to the disruption of cell proliferation, viability, and metabolism. Thus, the toxicity of magnetite NPs is studied by various methods and at different levels of living systems. Understanding the mechanisms of nanotoxicity should contribute to the targeted design of safe magnetic NPs.

According to the high operational costs, low stability, and reusability of enzymes, immobilization by nanoparticle gathering has increased in recent years. Iron oxide nanoparticles (magnetite nanoparticles, Fe3O4) have been prepared by mixing one volume of iron dioxide ions and two volumes of iron trioxide ions with HCl via the precipitation of iron salts by NH4OH. The features of magnetic nanoparticles have been studied by Atomic Force Microscopy (AFM), X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy (SEM). The prepared Fe3O4 was used in the adsorption method to immobilize the galactosidase enzyme. The immobilized enzyme has been compared with the crude one by optimizing time, PH, temperature, substrate solution concentration, and enzyme solution concentration. As a result, the immobilized enzyme has exhibited higher activity over long storage times, and a wide PH and temperature range than crude enzyme. In addition, whatever the substrate and enzyme concentrations, the activity of the immobilized enzyme increased over the non-immobilized one. As a result, a lower Km value for immobilized D-galactosidase indicates a higher affinity for the substrate than crude D-galactosidase. [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles (Fe3O4 NPs) are among the most effective Fenton-Like heterogeneous catalysts for degrading environmental contaminants. However, Fe3O4 NPs aggregate easily and have poor dispersion stability because of their magnetic properties, which seriously decrease their catalytic efficiency. In this study, a novel environmentally friendly method for synthesising Fe3O4@CA was proposed. Fe3O4 NPs were immobilized on the 3D cellulose aerogels (CAs) in order to augment the degradation efficiency of p-nitrophenol (PNP) treatment and make the separation of the catalyst accessible by vacuum filtration method. Besides, CAs were fabricated from a cellulose source extracted from water hyacinth by using different cross-linking agents, such as kymene (KM) and polyvinyl alcohol–glutaraldehyde system (PVA–GA), and other drying methods, including vacuum thermal drying and freeze drying, were evaluated in the synthesis process. As-synthesized samples were analysed by various methods, including Powder X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray analysis and Brunauer–Emmett–Teller. Then, using ultraviolet–visible spectroscopy, the difference in the degradability of PNP of the obtained material samples was also investigated to determine their potential applications. Results highlighted that the Fe3O4-3@CA-KF catalyst with an Fe3O4 loading of 0.40 g/gCA used KM as a cross-linker and the freeze-drying method demonstrated the highest PNP removal efficiency (92.5 %) in all Fe3O4@CA samples with a H2O2 content of 5 g/L. The degradation kinetics and well-fitted pseudo-first-order model were investigated. Notably, after five successive PNP degradation experiments, this catalyst retained ∼80 % of the ability to degrade PNP, indicating its outstanding reusability. In environmental remediation, this study provides valuable insights into the development of simply separated and high-efficiency catalysts for heterogeneous catalytic reactions.

To design more environmentally friendly, economical, and efficient demulsifiers for oily wastewater treatment, hydrophobic octadecylphosphonic acid (ODPA)-modified Fe3O4 nanoparticles (referred to as Fe3O4@ODPA) were prepared by condensation of hydroxyl groups between ODPA and Fe3O4 nanoparticles using the co-precipitation method. The prepared magnetite nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric/differential thermogravimetric (TG/DTG) analysis. The water contact angles (θW) of Fe3O4@ODPA nanoparticles were more than 120°, indicating hydrophobic nature, and the diameter of the obtained spherical-shaped magnetite nanoparticles was 12–15 nm. The ODPA coating amount (AO) (coating weight per gram Fe3O4) and specific surface area (SO) of Fe3O4@ODPA were 0.124–0.144 g·g−1 and 78.65–91.01 m2·g−1, respectively. To evaluate the demulsification ability, stability, and reusability, the magnetite nanoparticles were used to demulsify an n-hexane-in-water nanoemulsion. The effects of the magnetite nanoparticle dosage (CS), pH value of nanoemulsion, and NaCl or CaCl2 electrolytes on the demulsification efficiency (RO) were investigated. The RO of Fe3O4@ODPA samples was found to be higher than that of bare Fe3O4 samples (S0, ST, and SN) under all CS values. With the increase in CS, the RO of Fe3O4@ODPA samples initially increased and then approached equilibrium value at Cs = 80.0 g·L−1. A maximum RO of ~93% was achieved at CS = 100.0 g·L−1 for the Fe3O4@ODPA sample S2. The pH and two electrolytes had a minor effect on RO. The Fe3O4@ODPA nanoparticles maintained high RO even after being reused for demulsification 11 times. This indicates that the hydrophobic Fe3O4@ODPA samples can be used as an effective magnetite demulsifer for oil-in-water nanoemulsions. [ABSTRACT FROM AUTHOR]

The established blood donation and transfusion system has contributed a lot to human health and welfare, but for this system to function properly, it requires a sufficient number of healthy donors, which is not always possible. Pakistan was a country hit hardest by COVID-19 which additionally reduced the blood donation rates. In order to address such challenges, the present study focused on the development of RBC substitutes that can be transfused to all blood types. This paper reports the development and characterization of RBC substitutes by combining the strategies of conjugated and encapsulated hemoglobin where magnetite nanoparticles would act as the carrier of hemoglobin, and liposomes would separate internal and external environments. The interactions of hemoglobin variants with bare magnetite nanoparticles were studied through molecular docking studies. Moreover, nanoparticles were synthesized, and hemoglobin was purified from blood. These components were then used to make conjugates, and it was observed that only the hemoglobin HbA1 variant was making protein corona. These conjugates were then encapsulated in liposomes to make negatively charged RBC substitutes with a size range of 1–2 μm. Results suggest that these RBC substitutes work potentially in a similar way as natural RBCs work and can be used in the time of emergency. [ABSTRACT FROM AUTHOR]

In this work, magnetite nanoparticles (Fe3O4) that are well dispersed by a submicron sized carbon framework in a pomegranate shape are engineered using a flexible one-step spray pyrolysis strategy. Under inert gas atmosphere, the homogeneously mixed Fe3+ ions and chitosan (CS) molecules are in situ transformed to Fe3O4 nanoparticles and spherical nitrogen-doped carbon coating domains, respectively. Moreover, the obtained Fe3O4@C composite exhibits a unique submicron sized pomegranate configuration, in which favorable electric/ionic pathways have been constructed and the Fe3O4 nanoparticles have been effectively dispersed. When used as an anode electrochemical active material, the Fe3O4@C composite exhibits impressive lithium-ion storage capabilities, and maintains a reversible capacity of 500.2 mAh·g−1 after 500 cycles at a high current density of 1000 mA·g−1 as well as good rate capability. The strategy in this work is straightforward and effective, and the synthesized Fe3O4@C material has good potential in wider applications. [ABSTRACT FROM AUTHOR]

Neurolisteriosis is an infectious disease of the central nervous system (CNS) with a high mortality rate caused by Listeria monocytogenes. The CNS disorders suffer from inadequacy of drugs accessibility. An experimental in vivo model of neurolisteriosis was developed by oral administration of the bacteria in Wistar rats. It's speculated the capability of magnetite nanoparticles (MNPs) in ferrying gallic acid (GA), as a natural antimicrobial agent, through the blood-brain barrier (BBB) with the assistance of an external magnetic field (EMF). The capability of the formulated nanodrug in traversing through the BBB was approved by detecting blue spots in the Perls' Prussian staining of the brain tissue sections and by an increased iron content of the brain determined by the inductively coupled plasma spectroscopy. The GA release pattern and the nanodrug toxicity assay were promising. Anti-listeriosis effect of the formulated nanodrug was evaluated by molecular quantification of the relative abundance of survived bacteria in brain tissue samples. Besides, the relative expression of the listeriolysin O-encoding hly gene, the prominent virulence factor of L. monocytogenes, was determined using the rplD gene as a reference gene. The nanodrug-received rats showed a significantly less viable bacteria (13.2 ± 7.6%) and a 4.4-fold reduction in the relative expression of the hly gene in comparison to the sham group. Magnetite nanoparticles (MNPs) were synthesized by co-precipitation method, functionalized with GA, and finally coated with Tween 80. The physicochemical properties of the bare and surface modified materials were investigated using different techniques including X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopies, transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), dynamic light scattering (DLS) and Zeta Potential analyses, and vibrating sample magnetometry. In conclusion, MNPs displayed a considerable potential for drug delivery intentions to various target sites such as the CNS. Gallic acid exhibited a binary anti-listerial effect, the destruction of L. monocytogenes bacteria in addition to reducing the expression of the hly gene, which in turn causes reduced survivability of the bacteria in the CNS. [Display omitted] • A novel approach in neurolisteriosis treatment. • Magnetically driven drug delivery to CNS. • Oral administration of bacteria to develop the in vivo model of neurolisteriosis. • Binary anti-listerial effect of gallic acid as a natural compound. • Suppression of listeriolysin O-encoding gene expression by gallic acid. [ABSTRACT FROM AUTHOR]

Humic acid-modified magnetite nanoparticle (MnP-HA) has been synthesized using the co-precipitation method and applied for removal of [AuCl4]−. Modifying of MnP-HA was prepared with the mass ratio of MnP-HA=10:1 and 10:3. The HA was extracted from peat soil of Sambutan Village, East Kalimantan, Indonesia, by the recommended procedure of the International Humic Substances Society (IHSS). The saturation magnetization of MnP-HA was decreased compared to unmodified MnP. The interaction between MnP and HA was occurred due to the chemical bond between Fe from MnP with the carboxylic group from HA. The coating HA on the surface of MnP unchanged the formation of the crystal structure of MnP and increased the particle size. The optimum removal of [AuCl4]− on MnP and MnP-HA materials was optimum at pH 3.0. The Langmuir isotherm model with sorption capacity was 0.23, 4.85, and 4.65 mol g–1 for MnP, MnP-HA=10:1, and 10:3, respectively. Using a pseudo-second-order equation, the degradation of the kinetics model of [AuCl4]− on MnP, MnP-HA=10:1 and 10:3 with adsorption rate constant (k) were 0.02, 0.07, and 0.06 g.mol min–1.

The need for antennas with small dimensions with high performance has prompted various research to conduct experiments in terms of the structure and shape of the antenna and terms of material. This study proposes utilizing both artificially and engineered magneto-dielectric (MD) materials’ characteristics to miniaturize antenna dimension and improve antenna performance. The MD characteristics are realized through the SRR array structure as an antenna performance enhancer; and material synthesis as an antenna dimension reducer. MD material has been successfully synthesized, extracted, and characterized from a mixture of magnetite powder (Fe3O4), PDMS elastic polymer material (polydimethylsiloxane), and BaFe12O19. The parametric study results show that the antenna designed on MD material Sample C (PDMS: Fe3O4=1: 0.6) with a 3 $\times $ 3 SRR configuration gives the most optimal response. Simulations, optimizations, and measurements have been carried out to obtain an MD antenna that works at a frequency of 3.5 GHz, with a fractional bandwidth of 10% (360 MHz), radiation efficiency of 58.54%, and a maximum gain of up to 4.33 dBi. This antenna measures 30 $\times30$ mm or 64% smaller than conventional antennas. The proposed stacked MD antenna is compatible with 5G technology in the mid-band frequency range.

Nanomedicine plays a crucial role in the development of next-generation therapies. The use of nanoparticles as drug delivery platforms has become a major area of research in nanotechnology. To be effective, these nanoparticles must interact with desired drug molecules and release them at targeted sites. The design of these “nanoplatforms” typically includes a functional core, an organic coating with functional groups for drug binding, and the drugs or bioactive molecules themselves. However, by exploiting the coordination chemistry between organic molecules and transition metal centers, the self-assembly of drugs onto the nanoplatform surfaces can bypass the need for an organic coating, simplifying the materials synthesis process. In this perspective, we use gold-iron oxide nanoplatforms as examples and outline the prospects and challenges of using self-assembly to prepare drug-nanoparticle constructs. Through a case study on the binding of insulin on Au-dotted Fe3O4 nanoparticles, we demonstrate how a self-assembly system can be developed. This method can also be adapted to other combinations of transition metals, with the potential for scaling up. Furthermore, the self-assembly method can also be considered as a greener alternative to traditional methods, reducing the use of chemicals and solvents. In light of the current climate of environmental awareness, this shift towards sustainability in the pharmaceutical industry would be welcomed.

Background and Objectives: Magnetic wood is one of the wood nanotechnology products with a wide range of potential industrial applications. Superparamagnetic wood is generally produced by in situ synthesis of magnetic nanoparticles in the wood structure. Among the various wood species used for the production of magnetic wood, fast-growing species are gaining increasingly important. On the other hand, the inherent properties of wood, such as water absorption, dimensional instability, and susceptibility to biodegradation and weathering, may limit the potential of magnetic wood as an advanced engineering material. This study aimed to investigate the effect of furfurylation on modifying the physical and mechanical properties of superparamagnetic poplar wood prepared by in situ synthesis of magnetic nanoparticles. Materials and Methods: In situ synthesis of magnetite nanoparticles inside poplar wood (Populus deltoides) was carried out using a solution of iron II and III chlorides with a molar ratio of 2:1 in a vacuum/pressure chamber. Then the treated wood was converted to magnetic wood by draining the solution of iron cations and replacing it with a one-molar solution of sodium hydroxide. After washing the excess alkali solution and drying, the magnetic poplar wood was treated with two different concentrations of furfuryl alcohol solution under the vacuum/pressure system and converted into wood polymer after performing the required heat treatments. The samples were characterized using a field emission scanning electron microscope, X-ray diffraction, vibrating sample magnetometry, a static bending test, and long-term water absorption and thickness swelling tests. Results: The conversion of poplar wood to magnetic wood reduced the weight percentage gain (WPG) resulting from the furfurylation process. The saturation magnetization of the magnetic wood decreased significantly after furfurylation and conversion to the wood-polymer. Changing the concentration of the furfuryl alcohol solution did not substantially affect the saturation magnetization of the produced magnetic wood-polymers. The furfurylation treatment significantly reduced the samples' flexural strength and flexural modulus. The flexural properties of magnetic and non-magnetic wood polymer samples treated with the same concentration of furfuryl alcohol solution showed no significant difference. Microscopic examination of the fracture surface of the wood cell wall in the specimens subjected to the bending test showed that furfurylation changed the behavior of the fibers from ductile to brittle, which was consistent with the results of the bending test. On the other hand, as the WPG increased, the specimens' long-term water absorption and thickness swelling decreased. Magnetic wood-polymer samples showed higher values for water absorption and thickness swelling than non-magnetic wood-polymer specimens. Conclusion: Based on the results of this study, it is recommended that magnetic poplar wood, if it must be used in high-humidity environments, be converted to magnetic wood-polymer with furfuryl alcohol, provided it has the required mechanical properties. [ABSTRACT FROM AUTHOR]

In this paper, study the effects of magnetite nanomaterial Fe3O4 on the mechanical properties of epoxy. Dispersion of Fe3O4 nanoparticles in the epoxy resin was performed by ultrasonication. The samples of the nanocomposites were prepared using the casting method. The nanocomposites contain epoxy resins as a matrix material incorporated by different weight percentages of magnetite Fe3O4 that varies from 0wt.% to 15wt.% as a reinforcing material. The epoxy with the additive reinforcement materials Fe3O4 was slowly mixed in a sonication bath for 15 minutes, then the mixture poured into silicon molds. Field Emission Scanning Electron Microscopy FESEM and X-ray diffraction spectra XRD were used to characterize the morphological and structural properties of preparing samples and the distribution of Fe3O4 nanoparticles to the epoxy resin. Mechanical testing consists of tensile, hardness shore, and three-point flexural tests were performed on the samples at room temperature according to ASTM standards. The results showed that reinforcement by 15wt.% of Fe3O4 nanoparticles maximizes these mechanical properties of nanocomposites compared with pure epoxy except for the young modulus's preferred weight at 9 wt.%, this is due to aggregation of the additives nanomaterials in epoxy resin above 9 wt.%.

Magnetite/reduced graphene oxide nanocomposites (Fe 3 O 4 -rGO NCs) and magnetite nanoparticles (Fe 3 O 4 NPs) were added to enhance biohydrogen (bioH 2) production in dark fermentation. Concentration of supplements from 10 to 100 mg/L was appropriate to enhance bioH 2 production, and inhibition appeared once concentration exceeded 100 mg/L. The best bioH 2 yield was 198.30 mL/g glucose at 100 mg/L Fe 3 O 4 NPs and 225.60 mL/g glucose at 100 mg/L Fe 3 O 4 -rGO NCs, which was 42.97% and 62.65% higher than that in the blank group, respectively. Both Fe 3 O 4 NPs and Fe 3 O 4 -rGO NCs could intensify butyrate-type fermentation and change the hydrogen-producing microorganism cells morphology, but the enhancement effect of Fe 3 O 4 -rGO NCs was superior. Microbial community structure analysis showed that Clostridium-sensu-stricto-1 became more dominant ultimately by Fe 3 O 4 -rGO NCs. [Display omitted] • Fe 3 O 4 -rGO NCs were synthesized to enhance biohydrogen yield. • Fe 3 O 4 -rGO NCs enhanced disproportionation reaction of propionate to butyrate. • Fe 3 O 4 NPs and Fe 3 O 4 -rGO NCs could make the microbial cells longer and thicker. • Fe 3 O 4 -rGO NCs involved in intracellular and extracellular electron transfer. • Fe 3 O 4 -rGO NCs increased the abundance of Clostridium-sensu-stricto-1. [ABSTRACT FROM AUTHOR]

A major advance in drug discovery and targeted therapy directed at cancer cells may be achieved by the exploitation and immunomodulation of their unique biological properties. This review summarizes our efforts to develop novel chemo-thermo-immunotherapy (CTI therapy) by conjugating a melanogenesis substrate, N-propionyl cysteaminylphenol (NPrCAP: amine analog of tyrosine), with magnetite nanoparticles (MNP). In our approach, NPrCAP provides a unique drug delivery system (DDS) because of its selective incorporation into melanoma cells. It also functions as a melanoma-targeted therapeutic drug because of its production of highly reactive free radicals (melanoma-targeted chemotherapy). Moreover, the utilization of MNP is a platform to develop thermo-immunotherapy because of heat shock protein (HSP) expression upon heat generation in MNP by exposure to an alternating magnetic field (AMF). This comprehensive review covers experimental in vivo and in vitro mouse melanoma models and preliminary clinical trials with a limited number of advanced melanoma patients. We also discuss the future directions of CTI therapy. [ABSTRACT FROM AUTHOR]

Objective(s): Many patients die due to vascular, gastrointestinal lumen problems, and coronary heart diseases. Synthetic vessels that are made of biodegradable-nanofiber polymers have significant properties such as proper biodegradability and efficient physical properties such as high strength and flexibility. Some of the best options for supporting cells in soft tissue engineering and design are applications of thermoplastic polyurethane polymer in the venous tissue. In this study, the first nanoparticle-reinforced polymeric artificial prosthesis was designed and tested to be used in the human body.Materials and Methods: In this study, artificial gastrointestinal lumen were fabricated and prepared using a 3D printer. To improve cell adhesion, wettability properties and mechanical stability of elastin biopolymer with magnetic nanoparticles (MNPs) as well as single-walled carbon nanotubes (SWCNT) were prepared as separate filaments. MNPs were made in 5–7 mm sizes and then examined for mechanical, biological, and hyperthermia properties. Then, the obtained results of the gastrointestinal lumen were simulated using the Abaqus software package with a three-branch. The results were evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) for morphology and phase analysis. Results: The obtained results of the designed vessels showed remarkable improvement in mechanical properties of the SWCNT vessels and hyperthermia properties of the vessels containing the MNPs. The results of computational fluid dynamics (CFD) analysis showed that the artificial vessels had lower shear stress at the output. Conclusion: Five-mm MNP containing vessels showed noticeable chemical and biological properties along with ideal magnetic results in the treatment of thrombosis and vascular obstruction.

Magnetic hyperthermia therapy (MHT) is a highly promising therapeutic modality, mainly applied to deal with cancers and malignant tumors. To gain efficient magnetic hyperthermia therapy, magnetic nanoparticles (Fe 3 O 4) with improved heating efficiency are necessary. In this work, magnetite nanoparticles anchored on graphene oxide (GO/Fe 3 O 4) have been synthesized via chemical precipitation method, and anti-cancer drug have been introduced to form GO/Fe 3 O 4 loaded with doxorubicin hydrochloride (GO/Fe 3 O 4 -DXR) composite nanoparticles. X-ray diffraction analysis has been carried out to characterized the crystal structure of GO/Fe 3 O 4 nanoparticles with different mass ratios. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of doxorubicin hydrochloride (DRX) in GO/Fe 3 O 4 -DXR, while the structure of GO/Fe 3 O 4 nanoparticles with different mass ratios are studied by Transmission electron microscopy (TEM). And the heating efficacy of GO/Fe 3 O 4 -DXR nanoparticles were. investigated suitable for magnetic hyperthermia therapy under safe alternating magnetic fields (80 kHz, 30 kA m−1). Besides, the DXR loading and release data of GO/Fe 3 O 4 -DXR have been tested via ultraviolet–visible spectroscopy (UVVIS) in presence of the AC field. The above characteristics conform to temperature requirements of magnetic materials on medical applications, which infers that GO/Fe 3 O 4 -DXR particles show promising talent as targeted drug carriers and thermoseeds in MHT. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pumice and smectite are robust carriers for cell immobilization recycling. • Bacteria-pumice and bacteria-smectite nanocomposites are efficient for recycling. • Continuous production of microbial products from wastes was achieved. • Secondary treatment is unneeded in treating waste using the proposed nanocomposites. Recycling waste into commercial products is a profitable strategy but the lifetime of immobilized cells for long-term waste treatment remains a problem. This study presents alternative cell immobilization methods for valorizing food waste (FW) and oily food waste (OFW) to microbial carotenoids and proteins. Carriers (pumice or smectite), magnetite nanoparticles, and isolated photosynthetic bacteria were integrated to obtain magnetically recoverable bacteria-pumice and bacteria-smectite nanocomposites. After recycling five batches (50 d), chemical oxygen demand removal from FW reached 76% and 78% with the bacteria-pumice and bacteria-smectite nanocomposite treatments, respectively, and oil degradation in OFW reached 71% and 62%, respectively. Destructive changes did not occur, suggesting the durability of nanocomposites. The used nanocomposites had no impact on the lifespan of Moina macrocopa or water quality as assessed by toxicity analysis. Bacteria-pumice and bacteria-smectite nanocomposites are efficient for food waste recycling and do not require secondary treatment before being discharged into the environment. [ABSTRACT FROM AUTHOR]

Objective(s): Many patients die due to vascular, gastrointestinal lumen problems, and coronary heart diseases. Synthetic vessels that are made of biodegradable-nanofiber polymers have significant properties such as proper biodegradability and efficient physical properties such as high strength and flexibility. Some of the best options for supporting cells in soft tissue engineering and design are applications of thermoplastic polyurethane polymer in the venous tissue. In this study, the first nanoparticle-reinforced polymeric artificial prosthesis was designed and tested to be used in the human body. Materials and Methods: In this study, artificial gastrointestinal lumen were fabricated and prepared using a 3D printer. To improve cell adhesion, wettability properties and mechanical stability of elastin biopolymer with magnetic nanoparticles (MNPs) as well as single-walled carbon nanotubes (SWCNT) were prepared as separate filaments. MNPs were made in 5-7 mm sizes and then examined for mechanical, biological, and hyperthermia properties. Then, the obtained results of the gastrointestinal lumen were simulated using the Abaqus software package with a three-branch. The results were evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) for morphology and phase analysis. Results: The obtained results of the designed vessels showed remarkable improvement in mechanical properties of the SWCNT vessels and hyperthermia properties of the vessels containing the MNPs. The results of computational fluid dynamics (CFD) analysis showed that the artificial vessels had lower shear stress at the output. Conclusion: Five-mm MNP containing vessels showed noticeable chemical and biological properties along with ideal magnetic results in the treatment of thrombosis and vascular obstruction. [ABSTRACT FROM AUTHOR]

Magnetic Fe 3 O 4 nanoparticles were added into the aqueous phase to form nanofluid systems, in which ozone was used for the oxidation of tetracycline hydrochloride (TC) in the solution. The nanomaterials were characterized using SEM, XRD, EDS, and FT-IR. The effects of nanoparticles size, addition ratio, and number of cycles on the process of ozone oxidation of TC were investigated. The results indicated that the addition ratio of nanoparticles have a certain impact on the performance of ozone oxidation. When the addition ratio increased from 0.02% to 0.4%, the removal rate of TC in the solution was improved significantly. Besides, the particle size of nanoparticles showed a greater impact on ozone oxidation. At the nanoscale, Fe 3 O 4 nanoparticles exhibited significant strengthening properties, which is attributed to the construction of nanofluid systems. The removal rate of TC in solution decreased obviously with the increase of nanoparticles size. The Fe 3 O 4 nanoparticles with particle size of 20 nm showed the most significant effect on TC degradation. The recycling experiment showed that magnetic Fe 3 O 4 nanoparticles had stable regeneration performance. For three times of recycling treatment, with a Fe 3 O 4 addition ratio of 0.4%, the removal rate of TC reached 98.7%, 97.21%, and 96%, respectively. Based on the characterization results, the strengthening mechanism was analyzed. The experimental results indicated that construction of nanofluids systems could improve the utilization rate of ozone, and Fe 3 O 4 nanoparticles were reusable and easily recyclable.

Objective(s): Bioactive silicate ceramics have favorable features for applying as off-the-shelf bone and artificial tissue. Calcium silicate can enhance the generation of an immediate bond with host bone without an intervening rough surface in the bone layer. However, the silicate bioceramics have some drawback regarding their mechanical properties and chemical stabilities. Materials and Methods: In this study, magnetite nanoparticles (MNPs) as reinforcement were added to the three silicate bioceramics to investigate the physical and mechanical properties as well as their magnetic behavior as a case study and compare with other calcium silicate nanocomposite which are excellent candidates for hyperthermia applications. Then the artificial neural network (ANN) applied to the previous data to predict the mechanical and biological behavior of the bio-nanocomposite as output parameters. A predicted model was enhanced using ANN to measure the optimum size and reinforcement amount of the magnetite bio-nanocomposite. The results of the fabricated bio-nanocomposite were extracted experimentally corresponding to different MNPs weight fractions compared to the predicted model. Results: The X-ray diffraction (XRD), scan electron microscopy (SEM) technique were used to compare the porosity and porous tissue microstructure. Thereafter, an analytical solution is presented to express explicitly the physical and mechanical responses of the bulk/scaffold bio-nanocomposite. Conclusion: The obtained results showed the potential application of these calculations and analyses in a wide range of numerical studies. The comparison presented within the test and predicted values showed that the modeling outcomes were close to testing values.

Introduction: Advantages of using porous bio-nanocomposite scaffolds for maxillofacial fracture application and optimizing the internal surfaces of synthetic grafts using nanotechnology can accelerate the bone cell adhesion, mechanical properties and absorption rates. There are various studies that have been performed on porous scaffold, especially for the fractured and destroyed parts of the facial bones. The aim of this study was to investigate the experimental and numerical analysis of the porous scaffold, which undertakes static and dynamic loading conditions. Materials and Methods: The maxillofacial bone was modeled using the solid works software, and then it was inserted into the Abaqus software to achieve a more precise model that utilizes an isotropic linear substance. Thereafter, a proper micromechanical model reported evaluating the elastic modulus response on porosity value using various models. Additionally, an experimental analysis was conducted on a new calcium silicate (CS) bioceramic reinforced with magnetite nanoparticles (MNPs) using the space holder technique coated with the gentamicin drug loaded on gelatin polymer. The response of the bio-nanocomposites shape, which corresponds to different MNPs' weight fractions, was determined using the scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Results: The analysis of the scaffold implant showed that it is tightened at a torque of stiffness of 3mm in the implant, which leads to high mechanical tension. The results showed that the elastic modulus of the nanocomposites increased from 60±5 MPa to 145±5 MPa with increasing 15 wt% MNPs to the calcium silicate nanoparticles. Conclusion: The results indicated that addition of 15 wt% MNPs to the based bioceramics increased both compression strength and decrease the porosity value. [ABSTRACT FROM AUTHOR]

This review discussed about the green biosynthesis of magnetite nanoparticles (Fe 3 O 4 -NPs) and the biomedical applications, which mainly focus on the targeted anticancer drug delivery. Fe 3 O 4 -NPs have been studied and proved that Fe 3 O 4 -NPs can be used in various fields of application, due to "superparamagnetic" property that Fe 3 O 4 -NPs possessed. In targeted drug delivery system, drug loaded Fe 3 O 4 -NPs can accumulate at the tumor site by the aid of external magnetic field. This can increase the effectiveness of drug release to the tumor site and vanquish cancer cells without harming healthy cells. In order to apply Fe 3 O 4 -NPs in human body, Fe 3 O 4 -NPs have to be biocompatible and biodegradable to minimize the toxicity. So, green biosynthesis plays a crucial role as the biosynthesized Fe 3 O 4 -NPs is safe to be consumed by human because the materials used are from biological routes, such as plant extract and natural polymer. However, biosynthesis using plant extract is the most popular among them all as plant extract can act as both reducing and stabilizing agents in the synthesizing process of nanoparticles. This approach is not merely simple, yet economic and less waste production, which is environmental friendly. Several biomedical applications of Fe 3 O 4 -NPs are included in this review, but anticancer drug delivery study is discussed in detail. The criteria for Fe 3 O 4 -NPs to be used as drug delivery vehicle are discussed so as to study the optimum condition of Fe 3 O 4 -NPs in drug delivery application. Many researches showed the promising results of Fe 3 O 4 -NPs in treating cancer cells via in vitro study. Hence, this review is significant which summarize the vital points of Fe 3 O 4 -NPs in targeted anticancer drug delivery system. Conclusions have been made according to the literature reviewed and some points of view were proposed for future study. [ABSTRACT FROM AUTHOR]

• Fe 3 O 4 @SiO 2 -HAT-Cu(I) is a novel and efficient magnetic heterogeneous nanocatalyst. • Ease of preparation, stability, and cheapness of the catalyst. • Ease of the work-up procedure and catalyst separation by an external magnet field. • Reusability and potency of Fe 3 O 4 @SiO 2 -HAT-Cu(I) catalyst after several runs. • Use of green reaction media, simple performance, waste minimization, and atom-economy. A novel magnetically separable catalyst, the copper-hydroxyacetophenone thiosemicarbazone complex immobilized on silica-coated magnetite nanoparticles (Fe 3 O 4 @SiO 2 -HAT-Cu(I)), has been synthesized and characterized. The characterization included various techniques such as X-ray diffraction spectroscopy (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), dynamic laser scattering (DLS), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), atomic absorption spectroscopy (AAS), inductively coupled plasma-optical emission spectrometry (ICP-OES), and Fourier-transform infrared spectroscopy (FT-IR). The catalytic activity of Fe 3 O 4 @SiO 2 -HAT-Cu(I) was evaluated in a green aqueous mediated three-component synthesis of 1,2,3‐triazles. The catalyst efficiently facilitated the 'Click' Huisgen cycloaddition reaction between alkynes, sodium azide, alkyl bromides and/or epoxides in water/THF at 70 °C, resulting in good to excellent yields of 1,4-disubstituted 1,2,3‐triazle derivatives. Fe 3 O 4 @SiO 2 -HAT-Cu(I) is a new, low-cost, and magnetically separable heterogeneous catalyst that can be easily prepared and reused for multiple reaction runs without significant loss of catalytic activity. Synthesis, characterization, and application of copper-hydroxyacetophenone thiosemicarbazone complex immobilized on silica-coated magnetite nanoparticles (Fe 3 O 4 @SiO 2 -HAT-Cu(I)) as a novel magnetically retrievable nanocatalyst for the three-component synthesis of 1,4-disubstituted 1,2,3-triazoles are described. [Display omitted] [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles (nanoFe3O4) have been reported to facilitate direct interspecies electron transfer (DIET) between syntrophic bacteria and methanogens thereby improving syntrophic methanogenesis. However, whether or how nanoFe3O4 affects acetotrophic methanogenesis remain unknown. Herein, we demonstrate the unique role of nanoFe3O4 in accelerating methane production from direct acetotrophic methanogenesis in Methanosarcina-enriched cultures, which was further confirmed by pure cultures of Methanosarcina barkeri. Compared with other nanomaterials of higher electrical conductivity such as carbon nanotubes and graphite, nanoFe3O4 with mixed valence Fe(II) and Fe(III) had the most significant stimulatory effect on methane production, suggesting its redox activity rather than electrical conductivity led to enhanced methanogenesis by M. barkeri. Cell morphology and spectroscopy analysis revealed that nanoFe3O4 penetrated into the cell membrane and cytoplasm of M. barkeri. These results provide the unprecedented possibility that nanoFe3O4 in the cell membrane of methanogens serve as electron shuttles to facilitate intracellular electron transfer and thus enhance methane production. This work has important implications not only for understanding the mechanisms of mineral-methanogen interaction but also for optimizing engineered methanogenic processes.

Localized hyperthermia and the targeted release of the chemotherapy drug are one of the most challenging problems in chemo-hyperthermia therapy. In the present study, magnetite nanoparticles as a carrier of Temozolomide (TMZ) functionalized with folic acid-ligand (TMZ-MNP-FA) were designed and developed for targeted chemotherapy and radiofrequency hyperthermia of cancer cells. Nanoparticles were synthesized and characterized for hydrodynamic diameter, zeta potential, morphology, drug loading capacity, and in vitro RF-triggered release. Their cytotoxicity and efficacy as targeted drug delivery systems were evaluated in both cancer and normal cells and the therapeutic efficacy was analyzed on the C6 glioblastoma cancer cells. The C6 cells were treated with the nanoparticles and subjected to an alternating magnetic field (AMF) to reach a typical hyperthermia temperature of 43 °C. Then induction of apoptotic cells and the proliferation capacity of cancer cells were evaluated. The in vitro release studies exhibited that the drug release from TMZ-loaded magnetite nanoparticles was minimal at 37 °C but was noticeably boosted under an AMF irradiation. The developed targeted magnetite nanoparticles revealed higher cytotoxic effect and cellular uptake in folate-receptor overexpressing C6 cancer cells compared to OLN-93 normal cells. All results showed that combined magnetite chemo-hyperthermia (AMF + TMZ-MNP-FA) treatment was significantly more efficacious in cancer cells than hyperthermia, chemotherapy, or chemo-hyperthermia treatments (P < 0.0001). In conclusion, TMZ-MNP-FA had a key role to convert the externally delivered radiofrequency energy to heat in cancer cells. Additionally, localized hyperthermia triggered a TMZ release from the nanocarriers that resulted in cancer cell damage with synchronizing hyperthermia and chemotherapy. • The amount of TMZ-MNP-FA nanoparticle uptake into the C6 cancer cells was higher than OLN-93 normal cells. • The amount of FA-conjugated NP taken up by C6 glioblastoma cells was higher than that of NPs without FA. • The presence of magnetite NPs inside the cells under an AMF exposure dramatically increased the thermal dose. • AMF hyperthermia treatment could increase the Bax/Bcl-2 mRNA ratio in C6 cells. • TMZ-MNP-FA could serve as a powerful targeting AMF hyperthermia intensifier. [ABSTRACT FROM AUTHOR]

Highlights • Environmentally friendly process for magnetite nanoparticles production is proposed. • Alternating monopolar arrangement is superior than conventional monopolar. • No chemicals are needed for the process except water and iron plate. • The magnetite nanoparticles are promising for use as electrocatalyst for ORR. Abstract Magnetite nanoparticles have been successfully produced by the electro-oxidation of iron in water using a monopolar arrangement of iron electrodes. Two types of monopolar configurations were used: conventional monopolar (CM) and alternating monopolar (AM). The production rate of the magnetite nanoparticles could be increased significantly (∼30 times higher) by using the AM electrode arrangement compared to the production rate of one-pair of electrodes in the same system. The particle sizes ranged from 28 to 88 nm for the CM and from 20 to 25 nm for the AM arrangements. The performance of the AM arrangement was superior that of the CM arrangement in regard to production rate, particle size, and product purity. A numerical simulation showed distinguishable electric fields between the AM and CM arrangements. The magnetite particles produced using the CM arrangement contained impurities in the form of FeOOH and Fe 2 O 3. On the other hand, only magnetite was identified in the particles prepared using the AM arrangement. In addition, particle morphologies other than spherical could also be produced using the AM arrangement by changing the operating condition. The magnetite nanoparticles exhibited ferromagnetic properties. They can be used as a promising catalyst for oxygen reduction reactions in alkaline media. [ABSTRACT FROM AUTHOR]

Abstract This study explored the effect of [C 12 mim][Cl] ionic liquid on the equilibrium and dynamic interfacial tensions (IFTs) of n -heptane/water as a typical demonstrative model of oil/water system. The IL and the magnetite nanoparticles were synthesized and characterized in different ways including FTIR, 1HNMR, 13CNMR, mass spectrometry, SEM, TEM, DLS and XRD. The ionic liquid by itself caused an IFT reduction of 85.3% at critical micelle concentration of 0.025 mol/L and presence of nanoparticles intensified this effect, stronger under alkaline pHs. It was while nanoparticles alone had no considerable effect. The results of equilibrium IFT were nicely fitted with the Szyszkowski equation, and corresponding parameters were obtained. From dynamic IFT variations, it was found that the ionic liquid migration was adapted with the mixed diffusion from bulk to the interface. Therefore, the apparent diffusivity and the activation energy were obtained. Also, the stability of oil/water emulsions was increased in the simultaneous presence of the IL and nanoparticles. Confirming the results, the static contact angle of aqueous phase droplets surrounded by organic phase on the surface of quartz was raised in the presence of nanoparticles. Graphical abstract Unlabelled Image Highlights • The gemini imidazolium IL type surfactant was synthesized and indicated nanosize structure. • The nano gemini IL gave strong crude oil/water IFT reduction for the aim of CEOR. • The salts abnormal effects caused extremely IFT decrease with the IL in contrary to conventional surfactants. • Both temperature and pH parameters provided desired more IFT reductions. [ABSTRACT FROM AUTHOR]

The present study focusses on the enhancement of the catalytic activity and stability of an acetylesterase enzyme isolated from Staphylococcus spp. as Cross-Linked Enzyme Aggregates (CLEAs). The various parameters governing the activity of CLEAs were optimized. The magnetite and graphene oxide nanoparticles were successfully prepared via the chemical co-precipitation and Hummer's method, respectively. These nanoparticles supported the preparation as magnetite nanoparticle-supported cross-Linked Enzyme Aggregates (MGNP-CLEAs) and graphene oxide-supported Cross-Linked Enzyme Aggregates (GO-CLEAs). The activity and stability of these immobilized CLEAs were compared with the free enzyme at various temperature, pH, and organic solvents along with its storage stability and reusability. The immobilized preparations were analyzed by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared spectroscopy (FT-IR) techniques. Acetylesterase precipitated with 60% saturated ammonium sulfate salt (SAS) solution and cross-linked with 100 mM glutaraldehyde for 4 h at 30 °C was found to be optimal to produce CLEAs with highest activity recovery of 99.8%. The optimal pH at 8.0 and temperature at 30 °C remained the same for both the free and immobilized enzyme, respectively. Storage stability significantly improved for the immobilized enzyme as compared to free enzyme. SEM showed type-I aggregate and FT-IR revealed the successful immobilization of the enzyme. MGNP-CLEAs were found to have better activity and stability in comparison to other immobilized preparations. [ABSTRACT FROM AUTHOR]

• Energy diagrams for micromagnetic states in magnetite nanoparticles are calculated. • They essentially depend on the type of particle combined magnetic anisotropy. • Calculated single-domain diameters are in agreement with analytical estimates. Non uniform micromagnetic configurations are calculated in spheroidal magnetite nanoparticles with different semiaxis ratios, a / b = 0.5 – 2.0, using Landau-Lifshitz-Gilbert equation. We take into account a complex, combined type of particle magnetic anisotropy, associated with the presence of both cubic magneto-crystalline anisotropy and shape anisotropy of spheroidal magnetite nanoparticle. It is shown that, depending on the particle aspect ratio, there are different types of vortex states, which compete in energy with the uniform magnetization. It is also found that the single-domain diameters of magnetite nanoparticles significantly depend on the orientation of the cubic easy anisotropy axes with respect to the symmetry axis of a spheroid. The calculated single-domain diameters of spheroidal nanoparticles are in satisfactory agreement with analytical estimates. [ABSTRACT FROM AUTHOR]

Chemotherapy has been widely used to treat cancer; however, the non-specific systemic toxicity of chemotherapeutic agents has always been an issue. Local injection treatment is a strategy used to reduce the undesired adverse effects of chemotherapeutic drugs. In addition, chemotherapeutic agents combined with thermotherapy are effective in further enhancing therapeutic potency. In the present study, we prepared an injectable hydrogel, namely, doxorubicin (DOX)-loaded poly (lactic- co -glycolic acid) (PLGA) nanoparticle (DPN) and magnetite nanoparticle (MNP) embedded in alginate hydrogel (DPN/MNP-HG), where DPN and MNP were the chemotherapeutic and heating agents, respectively, for intratumoral thermo-chemotherapy. Injectable DPN/MNP-HG, which possesses solid-like elastic properties, was conveniently prepared via ionic cross-linking at room-temperature. When exposed to an alternating magnetic field (AMF), DPN/MNP-HG exhibited controllable heat generation with a reversible temperature-rise profile. Regarding the kinetics of DOX release, both with and without AMF, DPN/MNP-HG exhibited a slow initial burst and sustained release profile. In cytotoxicity studies and subcutaneous mouse cancer models, successful thermo-chemotherapy with DPN/MNP-HG resulted in significantly lower cell viability and increased tumor-growth suppression; mice also exhibited good tolerance to injected DPN/MNP-HG both with(+) and without AMF application. In conclusion, the proposed thermo-chemotherapeutic DPN/MNP-HG for local intratumoral injection is a promising formulation for cancer treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles (Fe 3 O 4 NPs) are among the most effective Fenton-Like heterogeneous catalysts for degrading environmental contaminants. However, Fe 3 O 4 NPs aggregate easily and have poor dispersion stability because of their magnetic properties, which seriously decrease their catalytic efficiency. In this study, a novel environmentally friendly method for synthesising Fe 3 O 4 @CA was proposed. Fe 3 O 4 NPs were immobilized on the 3D cellulose aerogels (CAs) in order to augment the degradation efficiency of p -nitrophenol (PNP) treatment and make the separation of the catalyst accessible by vacuum filtration method. Besides, CAs were fabricated from a cellulose source extracted from water hyacinth by using different cross-linking agents, such as kymene (KM) and polyvinyl alcohol-glutaraldehyde system (PVA-GA), and other drying methods, including vacuum thermal drying and freeze drying, were evaluated in the synthesis process. As-synthesized samples were analysed by various methods, including Powder X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray analysis and Brunauer-Emmett-Teller. Then, using ultraviolet-visible spectroscopy, the difference in the degradability of PNP of the obtained material samples was also investigated to determine their potential applications. Results highlighted that the Fe 3 O 4 -3@CA-KF catalyst with an Fe 3 O 4 loading of 0.40 g/g CA used KM as a cross-linker and the freeze-drying method demonstrated the highest PNP removal efficiency (92.5 %) in all Fe 3 O 4 @CA samples with a H 2 O 2 content of 5 g/L. The degradation kinetics and well-fitted pseudo-first-order model were investigated. Notably, after five successive PNP degradation experiments, this catalyst retained ∼80 % of the ability to degrade PNP, indicating its outstanding reusability. In environmental remediation, this study provides valuable insights into the development of simply separated and high-efficiency catalysts for heterogeneous catalytic reactions., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

The water pollution created by the textiles industry contains a large amount of azo dyes, such as Reactive Black 5 (RB5), which are recalcitrant in the environment. The feasibility and major mechanism of iron oxide nanoparticles (IONPs) in the removal of RB5 were investigated in this study. Our synthesized IONPs (17 nm) had a high surface area of 77.1 m 2 /g, possessed a magnetite crystal structure, and had a pH zpc of 5.56. The main removal mechanism of RB5 with IONPs was adsorption by electrostatic attraction. The adsorption isotherm of RB5 on IONPs fitted the Langmuir and Freundlich equations well. The removal efficiency of RB5 with IONPs decreased with increasing the initial RB5 concentrations but increased with the increase of NP dosage and temperature. The average adsorption enthalpy was 24 kJ/mol. As the pH increased, the removal efficiency of IONPs decreased due to electrostatic repulsion. The high magnetic property of our iron oxide NPs results in the NPs being easily recyclable from water: the NPs retained a 90% removal efficiency after ten cycles, suggesting their great potential for use in pollution treatments. [ABSTRACT FROM AUTHOR]

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We developed a stimuli-responsive poly(tetrafluoroethylene) (PTFE) microfiltration (MF) membrane by reversible conjunction of magnetite nanoparticles. We modified the magnetic particles with maleimide functional groups and attached them to a furan-modified PTFE membrane via a Diels–Alder (DA) cycloaddition reaction to prepare an anti-fouling membrane that responds to magnetism and temperature. The combined results of Fourier-transform infrared spectroscopy, X-ray diffractometry, vibrating sample magnetometry, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy investigations clearly showed that the maleimide-modified magnetic nanoparticles were successfully synthesized and coupled with the furan-modified PTFE MF membrane by the DA reaction. The modified membrane produced a micro-vortex under a rotating magnetic field, and showed a high resistance to fouling with a water flux higher than 50% of initial flux even after 30 min in the fouling test, whereas the neat membrane had a water flux falling below 20% of initial flux in 30 min. Moreover, the magnetite nanoparticles were readily and repeatedly regenerated on the MF membrane surface using a thermally driven peel-and-stick process; 75% of the water flux was recovered, even after three fouling cycles. [ABSTRACT FROM AUTHOR]