Review on magnetic spinel ferrite (MFe2O4) nanoparticles: From synthesis to application

Ternary AgFe2O4/SBA-16/SO3H Heterojunction Photocatalyst for the Sustainable Production of 5-Hydroxymethylfurfural under Mild Conditions

The use of solar energy to convert biomass and its derivatives into high-value chemicals has garnered significant interest as a sustainable alternative to fossil fuels. However, designing high-performance photocatalysts that can selectively catalyze biobased molecules remains a significant challenge in this field. In this paper, we describe the application of a ternary AgFe2O4/SBA-16/SO3H photocatalyst in the photocatalytic conversion of biomass-derived sugars to 5-hydroxymethylfurfural (HMF) using deep eutectic solvents (DESs) as green reaction media under visible light illumination. The photocatalyst was prepared by a facile sonication and postmodification method, and its crystal structure, functional groups, surface morphology, and optical features were analyzed through various characterization techniques. The influence of numerous essential variables on the photocatalytic production of HMF from fructose over the prepared photocatalyst was examined. The ideal reaction parameters were found to be 20 mg of photocatalyst quantity and 100 mg of fructose in choline chloride:glycerol under exposure to white LED light (9 W) at 80 °C, to afford 95% HMF yield in 2 h. The recyclability of the photocatalyst was established over five consecutive cycles, demonstrating its stability. This research provides an idea for AgFe2O4-based photocatalysts and a promising catalytic mode for biomass conversion using mild and efficient photocatalytic methodologies.

Optimization of variables for cadmium and copper removal using magnetic nanocomposite

This study aims to investigate cadmium and copper ultrasound-assisted removal efficiency on a laboratory scale using a cobalt ferrite/activated carbon (COF/AC) composite as an adsorbent. For this purpose, the effect of four independent variables (i.e., composite amount, pH, heavy metal concentrations, and ultrasound radiation time) on the performance of the cadmium and copper removal was investigated. The COF/AC composite was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and vibrating-sample magnetometer (VSM). The SEM and XRD techniques showed the successful synthesis of the COF/AC composite. The COF/AC composite has a surface area of 659.4 m2 g-1, an average diameter of 3.6 nm, and a pore volume of 0.482 cm3 g-1. In this study, R2 ˃ 0.99 and Adj-R2 ˃ 0.98 for both analytes signify a high agreement between the obtained laboratory data and the model-predicted data. The analysis results for heavy metal removal revealed the following optimal conditions: the composite content of 0.22 g, ultrasound radiation time of 22 min, concentration of 19 mg L-1, and pH of 5. Under optimal conditions, the maximum removal efficiency reached 93.46% and 97.45% for cadmium and copper, respectively. The COF/AC composite reuse results showed no significant decrease in removal efficiency up to 4 times of use during the adsorption and desorption process. Analysis of real samples showed that the removal rates of cadmium and copper were 89.62% and 96.37%, respectively.

Magnetic and antibacterial properties of substituted cobalt spinel ferrite nanocomposites synthesized via henna green microwave hydrothermal method

A novel henna-green/microwave-assisted hydrothermal method was applied to synthesize cobalt-manganese spinel ferrite nanocomposites. This eco-friendly approach, utilizing henna extract as a capping agent, combined with a microwave-assisted hydrothermal technique, offers advantages such as environmental sustainability, time, and energy efficiency. Examined parameters included pH (10 ± 1), temperatures (175 ± 25 °C), durations (15, 30 ± 15 min), and forty milliliters of henna extract prepared with varying henna quantities (five, ten, or fifteen grams per hundred milliliters of water). Post-optimization, various substituents like nickel and chromium were explored. Samples were calcined at 500 °C, 700 °C, and 900 °C, and analyzed using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and magnetic property assessments. XRD revealed a cubic face-centered spinel ferrite and hematite structure. SEM and TEM showed diverse morphologies (rod-like, flower-like, polygonal) influenced by synthesis conditions and substituents. XPS confirmed Co2+, Mn2+, Ni2+, Fe3+, and Cr3+ presence in the spinel lattice. The nanocomposites exhibited ferromagnetic behavior with saturation magnetization (Ms) values from 23.53 to 55.15 emu/g. Chromium substitution showed the best antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans. This study highlights the potential of the henna-green/microwave-assisted hydrothermal method for controlled synthesis of substituted cobalt spinel ferrite nanocomposites with tunable properties for various applications.

Reactions of fluid and lattice oxygen mediated by interstitial atoms at the TiO2(110)-water interface

O2 interacts with TiO2 surfaces in numerous aqueous reactions for clean hydrogen production, wastewater cleanup, reduction of CO2 and N2, and O2 sensing. In many cases, these reactions involve reversible exchange of O with the solid, whose participation is usually thought to require oxygen vacancies (VO). Based on measurements of oxygen isotopic self-diffusion in rutile TiO2 under water, this work proposes a different perspective centered on O interstitial atoms (Oi). Experiments with varying concentrations of O2 and mole fractions of 18O show that the (110) surface facilitates O exchange with both the H2O liquid and its dissolved O2. First-principles calculations indicate that on-top and "surface Oi" configurations of adsorbed O participate sequentially in the exchange process. Adsorbed OH appears to provide a single pathway for H2O and O2 to contribute oxygen, although fitting the diffusion data to simple models indicates that H2O contributes more. Because rutile TiO2 is a prototypical metal oxide, this picture based on Oi probably generalizes in many cases to other oxides - explaining important aspects of their thermal, electrochemical, and photochemical reactions with dissolved O2.

Preparation, Characterization, and Antibacterial Activity of Various Polymerylated Divalent Metal-Doped MF2O4 (M = Ni, Co, Zn) Ferrites

The continuous discovery of novel effective antibacterial agents using nano-based materials is of high significance. In this study, we utilized Polymerylated divalent-metal-doped ferrite nanoparticles (PMFe2O4 NPs) and studied their antibacterial inhibition effects. Different panels of PVP- and PEG-coated metal-doped MFe2O4 (M ≅ Co, Ni, and Zn) were prepared via the Ko-precipitation Hydrolytic Basic (KHB) methodology and thoroughly analyzed using TEM, XRD, FTIR, and VSM. The as-synthesized doped ferrites displayed stable quasi-spherical particles (7-15 nm in size), well-ordered crystalline cubic spinel phases, and high-saturation magnetizations reaching up to 68 emu/g. The antibacterial efficacy of the doped ferrites was then assessed against a Gram-negative E. coli bacterial strain. The results demonstrated that both metal doping and polymer functionalization influence the antimicrobial efficacies and performance of the ferrite NPs. The presence of the PVP polymer along with the divalent metal ions, particularly Co and Ni, resulted in the highest antibacterial inhibition and effective inactivation of the bacterial cells. The antibacterial performance was as follows: PVP-CoFe2O4 > PVP-NiFe2O4 > PVP-ZnFe2O4. Lastly, cell viability assays conducted on human breast fibroblast (HBF) cells confirmed the good safety profiles of the doped ferrites. These interesting results demonstrate the distinctive inhibitory features of the biocompatible metal-doped ferrites in enhancing bacterial killing and highlights their promising potential as effective antimicrobial agents, with possible applications in areas such as water disinfection, biomedical devices, and antimicrobial coatings.

Development of manganese ferrite coated with Prussian blue as an efficient contrast agent for applications in magnetic resonance imaging

Magnetic iron oxide nanoparticles are frequently utilized as contrast agents in magnetic resonance imaging (MRI). However, the release of iron ions leads to the formation of reactive oxygen species (ROS), resulting in cell damage. In this study, we developed MRI contrast agents containing amine-functionalized MnFe2O4 nanoparticles with a Prussian blue (PB) surface coating to enhance their biocompatibility. The prepared MNPs were embedded in polyvinylpyrrolidone and dried. The resulting crystals can be redispersed in water immediately before use, forming a stable colloid. The particle size of nanoparticles (43 ± 13 nm) is suitable for the intended application. The values of Hc (52 Oe) and Mr (3.7 emu/g) for the particles indicate a soft ferromagnetic nature. The coating of the particles with PB results in a significant reduction of their toxicity, as evidenced by a toxicological test on HEK293 cells. This colloid was tested in vitro as an MRI contrast agent as well as in healthy animal. The longitudinal relaxivity (r1) of the PB-MnFe2O4-NH2 sample was determined to be 0.01 (mg/mL)-1ms- 1. The transversal relaxivity was measured as well (r2: 0.77 (mg/mL)-1ms- 1 and r2*: 1.48 (mg/mL)-1ms- 1, which were in the same range as Feraheme and Endorem. Prussian blue-coated MnFe2O4 emerges as a promising T2-weighted contrast material, representing a novel combination of two well-known contrast-capable materials.

Magnetic Investigation of Se/In Codoped Co0.5Ni0.5Fe2O4 Spinel Nanoparticles Synthesized via the Sonochemical Route

The magnetic traits of sonochemically synthesized Co0.5Ni0.5InxSe3xFe2-5xO4 nanoparticles [(In/Se → Co0.5Ni0.5Fe2O4) (x ≤ 0.1) NPs] have been investigated in detail. X-ray powder diffraction analysis confirmed the purity and cubic phase crystalline structure of all products. The products' chemical composition has been confirmed by EDX and elemental mapping analyses. The magnetization characteristics of Co0.5Ni0.5In2xSe3xFe2-6xO4 (In/Se → Co0.5Ni0.5Fe2O4) (x ≤ 0.1) NPs revealed superparamagnetic behavior at room temperature and ferrimagnetic behavior at low temperatures (Ts). The blocking temperature (TB) that defines the superparamagnetic-ferrimagnetic state transition was also determined via analysis of the ZFC and FC magnetization curves. TB was found to move to lower Ts as the amount of selenium amount increased. Moreover, the undoped Co0.5Ni0.5Fe2O4 NPs displayed the highest magnetic characteristics (such as Ms, Mr, Hc, Keff, and nB), which are depressed after In/Se codoping. The superparamagnetic feature could be promising for some interesting applications, including biosensing, magnetic hyperthermia, magnetic resonance imaging, and targeted drug delivery, while the ferrimagnetic behavior can make the material interesting for electrical applications.

Magnetizing Biotech-Advances in (In Vivo) Magnetic Enzyme Immobilization

Industrial biocatalysis, a multibillion dollar industry, relies on the selectivity and efficacy of enzymes for efficient chemical transformations. However, enzymes, evolutionary adapted to mild biological conditions, often struggle in industrial processes that require harsh reaction conditions, resulting in reduced stability and activity. Enzyme immobilization, which addresses challenges such as enzyme reuse and stability, has therefore become a vital strategy for improving enzyme use in industrial applications. Traditional immobilization techniques rely on the confinement or display of enzymes within/on organic or inorganic supports, while recent advances in synthetic biology have led to the development of solely biological in vivo immobilization methods that streamline enzyme production and immobilization. These methods offer added benefits in terms of sustainability and cost efficiency. In addition, the development and use of multifunctional materials, such as magnetic (nano)materials for enzyme immobilization, has enabled improved separation and purification processes. The combination of both "worlds," opens up new avenues in both (industrial) biocatalysis, fundamental science, and biomedicine. Therefore, in this review, we provide an overview of established and recently emerging methods for the generation of magnetic protein immobilizates, placing a special focus on in vivo immobilization solutions.

Printing rare-earth-free (REF) magnetic inks: synthesis, formulation, and device applications

Additive manufacturing (AM) of magnetic materials has recently attracted increasing interest for various applications but is often limited by the high cost and supply chain risks of rare-earth-element (REE) magnetic precursors. Recent advances in nanomanufacturing have enabled the development of rare-earth-free (REF) magnetic materials, such as spinel ferrites, hexaferrites, MnAl, MnBi, Alnico, FePt, and iron oxides/nitrides, which offer promising alternatives for printing high-performance magnetic devices. This review provides a detailed overview of the latest developments in REF magnetic materials, covering both synthesis strategies of REF magnetic materials/nanomaterials and their integration into AM processes. We summarize the design and formulation of magnetic inks, emphasizing the unique properties of REF ferromagnetic and ferrimagnetic systems and their adaptability to AM techniques like direct ink writing, inkjet printing, aerosol jet printing, and screen printing. Key advancements in materials chemistry, ink rheology, and device performance are discussed, highlighting how the structure of REF magnetic materials impacts device functionalities. This review concludes with a perspective on the pressing challenges and emerging opportunities in AM of REF magnetic inks. Through this review, we aim to offer insights into the structure-processing-property relationship of REF magnetic inks and guide the design of next-generation printable magnetic systems in a scalable, cost-effective, and sustainable manner.

Solvothermal synthesis of polyvinyl pyrrolidone encapsulated, amine-functionalized copper ferrite and its use as a magnetic resonance imaging contrast agent

Copper ferrite nanoparticles for use as MRI contrast agents were synthesized using two different methods. A novel microwave-assisted (MW) solvothermal method was developed and compared to a conventional 12-hour synthesis (Reflux) as an eco-friendlier approach. This innovative synthesis method successfully produced nanoparticles with enhanced properties compared to traditional ferrite materials. The nanoparticles' morphological and magnetic properties were evaluated and tested in in-vivo MRI studies. The results revealed both similarities and differences between the amine-functionalized copper ferrite nanoparticles. FTIR, XRD, HRTEM, and VSM analyses indicated improved properties in the CuFe2O4-NH2 MW particles, while AFM confirmed successful polymer encapsulation of the nanoparticles. For the CuFe2O4-NH2 MW sample, 76.8 wt% copper ferrite and 23.2 wt% magnetite were detected, with crystallite sizes of 8 ± 2 nm and 13 ± 2 nm, respectively. In the CuFe2O4-NH2 Refl. sample, in addition to these two magnetic phases, larger copper particles (31.6 wt%) were also formed. DLS analysis demonstrated that the CuFe2O4-NH2 MW sample exhibited excellent colloidal stability, maintaining its size distribution in aqueous media for 3 hours without aggregation, unlike the CuFe2O4-NH2 Refl. sample, which showed slight aggregation. The CuFe2O4-NH2 MW sample displayed superparamagnetic behavior (Ms: 15 emu/g, Mr: 0 emu/g, Hc: 0 Oe), while the CuFe2O4-NH2 Refl. sample exhibited ferromagnetic characteristics (Ms: 40 emu/g, Mr: 1.35 emu/g, Hc: 30 Oe). Both samples produced comparable results during in vitro MRI measurements, showing similar T2* relaxation and signal characteristics. Further in vivo studies demonstrated that both samples induced significant hypointense changes. The study provides valuable insights into the synthesis, properties, and potential applications of these materials, emphasizing the importance of eco-friendly methods and the optimization of ferrite-based MRI contrast agents.

One-Pot Synthesis and Characterization of Magnetic α-Fe2O3/CuO/CuFe2O4 Nanocomposite for Multifunctional Therapeutic Applications

This study demonstrates a novel nanostructured drug delivery system utilizing α-Fe2O3/CuO/CuFe2O4 ternary nanocomposite for effective drug transport in sick tissues. Centella Asiatica plant extract was employed to synthesize the Fe2O3/CuO/CuFe2O4 nanocomposite via sol-gel auto combustion technique. The structural and morphological characteristics of the nanocomposite were investigated by XRD, FT-IR, SEM, EDX, and VSM for magnetic properties. The XRD analysis demonstrates the successful synthesis of Fe2O3/CuO/CuFe2O4 nanocomposite with an average crystallite size of 18.393 nm. The antioxidant and antifungal capabilities of this nanocomposite were assessed for its biological activity. A notable inhibitory zone was observed when tested against the Alternaria spp. and Bipolaris sorokiniana fungi. An IC50 value of 109.88 μg/ml was found in the DPPH test, indicating that the nanocomposite exhibited remarkable antioxidant characteristics. Subsequently, metronidazole was encapsulated with a success rate of 55.53 % at pH 1.2, while at pH 7.4 it gained 57.83 %. The drug release of nanocomposite at pH 1.2 after 330 min was 43.41 % and at pH 7.4 after 300 min it was 52.3 %. The results indicate its potential as an excellent candidate for drug delivery. Furthermore, pH was found to be an effective catalyst in the drug loading and release processes.

X and Q-band EMR study of ultrasmall Zn1-xMnxFe2O4 spinel nanoparticles fabricated under nonhydrolytic conditions

In this work, we are showing the results of the X- and Q-band electron magnetic resonance measurements of ultra-small Zn1-xMnxFe2O4 nanoparticles (ca. 8 nm) with a very narrow size distribution. The chosen synthetic route allows for precise structural modifications with a broad concentration range (x = 0, 0.2, 0.5, 0.8, 1). The crystal structure was evaluated by means of X-ray diffraction, while cell parameters were calculated using Rietveld refinement. EMR spectral studies indicated that the prepared nanoparticles were superparamagnetic. The linewidth of EMR signal for any ferrite material generally originates from two sources: (a) magnetic dipole-dipole interactions among particles and (b) interparticle superexchange interactions between magnetic ions through oxygen ions. Observed effects are more complex interactions than in pure zinc and manganese ferrites. As a result of the study, a relationship was observed between the composition of the material and the magnetic properties with striking antiferromagnetism and ferrimagnetism change. Hence, by structural modification of materials, the magnetic character (FM-AFM-FiM) can be controlled.

MnFe2O4-loaded bamboo pulp carbon-based aerogel composite: synthesis, characterization and adsorption behavior study for heavy metals removal

Heavy metal wastewater is a direct threat to the ecological environment and human health because it is highly toxic at low concentrations. Therefore, it is very important to explore and develop efficient wastewater treatment agents. MnFe2O4-loaded bamboo pulp carbon-based aerogel (MCA) is prepared by directional freeze-drying and carbonization. SEM, TEM, XPS, XRD, BET and FTIR are used to evaluate the physical and chemical properties of MCA. Meanwhile, the adsorption performances of MCA on Pb2+, Cu2+ and Cd2+ are also studied by adsorption kinetics, isothermal curves and thermodynamics. The results show that the adsorption process involves chemical adsorption and physical adsorption, and the adsorption process is a spontaneous endothermic process. The maximum adsorption capacities of MCA for Pb2+, Cu2+ and Cd2+ obtained in the adsorption isotherm experiments were 74.38, 84.21 and 73.63 mg g-1, respectively, showing excellent adsorption performance for Pb2+, Cu2+ and Cd2+. Therefore, the MCA has potential application for wastewater purification of heavy metals containing Pb2+, Cu2+ and Cd2+, meanwhile, this study provides some guidance for the design and application of microspheres for the separation and removal of Pb2+, Cu2+ and Cd2+.

Magnetic nanoparticle-catalysed synthesis of quinoline derivatives: A green and sustainable method

Greener and sustainable synthetic strategies have been evolving as the demanding domain of organic synthesis during the last decade. Green synthesis involves the development of method that decrease or eliminate the use of hazardous chemicals, and make use of renewable or recyclable resources. By incorporating the fundamentals and methodologies of green synthesis, organic chemists have the ability to develop valuable organic molecular frameworks which also demonstrate a strong commitment to environmental sustainability. In this context, the nanoparticle has garnered significant interest due to its various features, adhering to the principles of green synthesis. Specifically, magnetic nanoparticles have been trending extensive uses in green synthesis throughout the past decade. The role of magnetic nanoparticle has an irreplaceable place in the synthesis of biologically valuable frameworks named as quinoline. Quinoline are considered a privileged structure among organic compounds and offer a promising avenue for identifying lead structures in the search of new synthetic molecules (Saquinavir, Imiquimod and Reabamipide) having potential medicinal values and other important prospects. So, it's always indeed to the organic and medicinal chemist to develop biologically active frameworks by the green synthesis. The current manuscript consolidates the existing research on properties of environment-friendly magnetic nanoparticles for generating an extended range of valuable quinoline derivatives.

Combination Using Magnetic Iron Oxide Nanoparticles and Magnetic Field for Cancer Therapy

Iron oxide nanoparticles (MNPs) demonstrate notable benefits in magnetic induction, attributed to their distinctive physical and chemical attributes. Emerging cancer treatment utilizing magnetic fields have also gathered increasing attention in the biomedical field. However, the defects of difficult dispersion and poor biocompatibility of MNPs seriously hinder their application. In order to overcome its inherent defects and maximize the therapeutic potential of MNPs, various functionalized MNPs have been developed, and numerous combined treatment methods based on MNPs have been widely studied. In this review, we compare and analyze the common nanoparticles based on MNPs with different sizes, shapes, and functional modifications. Additionally, we introduced the therapeutic mechanisms of the strategies, such as magnetically controlled targeting, magnetic hyperthermia, and magneto-mechanical effect, which based on the unique magnetic induction capabilities of MNPs. Finally, main challenges of MNPs as smart nanomaterials were also discussed. This review seeks to offer a thorough overview of MNPs in biomedicine and a new sight for their application in tumor treatment.

Recent advancements and clinical aspects of engineered iron oxide nanoplatforms for magnetic hyperthermia-induced cancer therapy

The pervasiveness of cancer is a global health concern posing a major threat in terms of mortality and incidence rates. Magnetic hyperthermia (MHT) employing biocompatible magnetic nanoparticles (MNPs) ensuring selective attachment to target sites, better colloidal stability and conserving nearby healthy tissues has garnered widespread acceptance as a promising clinical treatment for cancer cell death. In this direction, multifunctional iron oxide nanoparticles (IONPs) are of significant interest for improved cancer care due to finite size effect associated with inherent magnetic properties. This review offers a comprehensive perception of IONPs-mediated MHT from fundamentals to clinical translation, by elucidating the underlying mechanism of heat generation and the related influential factors. Biological mechanisms underlying MHT-mediated cancer cell death such as reactive oxygen species generation and lysosomal membrane permeabilization have been discussed in this review. Recent advances in biological interactions (in vitro and in vivo) of IONPs and their translation to clinical MHT applications are briefed. New frontiers and prospects of promising combination cancer therapies such as MHT with photothermal therapy, cancer starvation therapy and sonodynamic therapy are presented in detail. Finally, this review concludes by addressing current crucial challenges and proposing possible solutions to achieve clinical success.

Chitosan-coated manganese ferrite nanoparticles enhanced Rhodotorula toruloides carotenoid production

The present study aims to analyze the interaction between Rhodotorula toruloides and magnetic nanoparticles and evaluate their effect on carotenoid production. The manganese ferrite nanoparticles were synthesized without chitosan (MnFe2O4) and chitosan coating (MnFe2O4-CS) by the co-precipitation method assisted by hydrothermal treatment. XRD (X-ray diffraction), Magnetometry, Dynamic Light Scattering (DLS) and FTIR (Fourier-Transform Infrared Spectroscopy), are used to characterize the magnetic nanoparticles. The crystallite size of MnFe2O4 was 16 nm for MnFe2O4 and 20 nm for MnFe2O4-CS. The magnetic saturation of MnFe2O4-CS was lower (39.6 ± 0.6 emu/g) than the same MnFe2O4 nanoparticles (42.7 ± 0.3 emu/g), which was attributed to the chitosan fraction presence. The MnFe2O4-CS FTIR spectra revealed the presence of the characteristic chitosan bands. DLS demonstrated that the average hydrodynamic diameters were 344 nm for MnFe2O4 and 167 nm for MnFe2O4-CS. A kinetic study of cell immobilization performed with their precipitation with a magnet demonstrated that interaction between magnetic nanoparticles and R. toruloides was characterized by an equilibrium time of 2 h. The adsorption isotherm models (Langmuir and Freundlich) were fitted to the experimental values. The trypan blue assay was used for cell viability assessment. The carotenoid production increased to 256.2 ± 6.1 µg/g dry mass at 2.0 mg/mL MnFe2O4-CS. The use of MnFe2O4-CS to stimulate carotenoid yeast production and the magnetic separation of biomass are promising nanobiotechnological alternatives. Magnetic cell immobilization is a perspective technique for obtaining cell metabolites.

Fabrication of Nd-Ho Cosubstituted Co0.5Ni0.5Fe2O4 Nanospinel Ferrites and Exploration of Their Microstructure, Magnetic, and Electromagnetic Characteristics

The composition and hyperfine structures of Nd3+-Ho3+ ions cosubstituted CoNi nanospinel ferrites (Co0.5Ni0.5NdxHoxFe2-2xO4 (x ≤ 0.05) NSFs) as well as their magnetic and electrodynamic behavior have been presented. The compound Nd-Ho → CoNiFe2O4 (x ≤ 0.05) NSFs were produced using the sol-gel method. XRD powder patterns indicated phase- and substituent-induced modifications of crystallites. The SEM analysis indicated the homogeneous distribution of grains with Nd-Ho cosubstitution. It was found that the values of x had an impact on the hyperfine magnetic field of the A and B sites. The cation distribution was determined by using Mössbauer spectroscopy. The M-H loops' investigations showed that the current NSFs behave ferrimagnetically at both room and low temperatures. An almost continuous rise in the strength of the coercive field was noticed with a rise in Ho-Nd content. The value of calculated squareness ratio values was above 0.5 at both temperatures, entailing that the studied NSFs' structure is made of single magnetic domains. The electromagnetic characteristics of the samples can be explained by the main contribution to electromagnetic absorption being the electric energy losses. Electromagnetic absorbed materials can be applied to provide electromagnetic compatibility and develop functional electromagnetic shields.

Thermomechanical properties of confined magnetic nanoparticles in electrospun polyacrylonitrile nanofiber matrix exposed to a magnetic environment: structure, morphology, and stabilization (cyclization)

Electrospun metal oxide-polymer nanofiber composites hold promise for revolutionizing biomedical applications due to their unique combination of electronic and material properties and tailorable functionalities. An investigation into the incorporation of Fe-based nanofillers for optimizing the polyacrylonitrile matrix was conducted, where the systematic and organized arrangement of inorganic components was achieved through non-covalent bonding. These carefully dispersed nanomaterials exhibit the intrinsic electronic characteristics of the polymers and concurrently respond to external magnetic fields. Electrospinning was utilized to fabricate polyacrylonitrile nanofibers blended with Fe2O3 and MnZn ferrite nanoparticles, which were thermomechanically, morphologically, and spectroscopically characterized in detail. With the application of an external magnetic field in the course of dynamic mechanical measurements under tension, the storage modulus of the glass transition T g of PAN/Fe2O3 rises at the expense of the loss modulus, and a new peak emerges at ∼350 K. For the PAN/MnZn ferrite nanofibers a relatively larger shift in T g (from ∼367 K to ∼377 K) is observed, emphasizing that in comparison to Fe2O3, Mn2+ ions in particular enhance the material's magnetic response in MnZn Ferrite. The magnetic oxide particles are homogenously dispersed in polyacrylonitrile, corroborated by high-resolution scanning electron microscopy. Both nanopowder additions lead to a slight shift of the peak towards larger angles, related to the shrinkage of the polymer. Produced nanofibers with high mechanical and heating efficiency can optimize the influence of the intracellular environment, magnetic refrigeration systems and sensors/actuators by their magnetic behavior and heat generation.

Targeting nanoplatform synergistic glutathione depletion-enhanced chemodynamic, microwave dynamic, and selective-microwave thermal to treat lung cancer bone metastasis

Once bone metastasis occurs in lung cancer, the efficiency of treatment can be greatly reduced. Current mainstream treatments are focused on inhibiting cancer cell growth and preventing bone destruction. Microwave ablation (MWA) has been used to treat bone tumors. However, MWA may damage the surrounding normal tissues. Therefore, it could be beneficial to develop a nanocarrier combined with microwave to treat bone metastasis. Herein, a microwave-responsive nanoplatform (MgFe2O4@ZOL) was constructed. MgFe2O4@ZOL NPs release the cargos of Fe3+, Mg2+ and zoledronic acid (ZOL) in the acidic tumor microenvironment (TME). Fe3+ can deplete intracellular glutathione (GSH) and catalyze H2O2 to generate •OH, resulting in chemodynamic therapy (CDT). In addition, the microwave can significantly enhance the production of reactive oxygen species (ROS), thereby enabling the effective implementation of microwave dynamic therapy (MDT). Moreover, Mg2+ and ZOL promote osteoblast differentiation. In addition, MgFe2O4@ZOL NPs could target and selectively heat tumor tissue and enhance the effect of microwave thermal therapy (MTT). Both in vitro and in vivo experiments revealed that synergistic targeting, GSH depletion-enhanced CDT, MDT, and selective MTT exhibited significant antitumor efficacy and bone repair. This multimodal combination therapy provides a promising strategy for the treatment of bone metastasis in lung cancer patients.

Magnetic Nanoparticles: A Comprehensive Review from Synthesis to Biomedical Frontiers

Nanotechnology has opened new doors of exploration, particularly in materials science and healthcare. Magnetic nanoparticles (MNP), the tiny magnets, because of their various properties, have the potential to bring about radical changes in the field of medicine. The distinctive surface chemistry, nontoxicity, biocompatibility, and, in particular, the inducible magnetic moment of magnetic materials has attracted a great deal of interest in morphological structures from a variety of scientific domains. This review presents a concise overview of MNPs and their crucial properties and synthesis routes. It also aims to highlight the continuous synthesis methods available for MNP production. In recent years, the use of computational methods for understanding the behavior of nanoparticles has been on the rise. Thus, we also discuss the numerical models developed to understand how magnetic nanoparticles can be used in magnetic hyperthermia and targeting the Circle of Wilis. With the increasing use of MNPs in biomedical applications, it becomes necessary to understand the mechanisms of toxicity, which are elucidated in this review. The review focuses on the biomedical applications of MNPs in drug delivery, theranostics, and MRI contrasting agents. We anticipate that this article will broaden the perspective on magnetic nanoparticles and help to understand their functionality and applicability better.

Biodegradable Acid-Based Fe2MnO4 Nanoparticles for Water Remediation

This study demonstrated the synthesis of Fe2MnO4 modified by citric acid, a biodegradable acid, using a simple co-precipitation method. Characterization was performed using qualitative analysis techniques such as Fourier-transformed infrared spectroscopy, scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy, X-ray diffraction, selected-area electron diffraction, N2 adsorption-desorption, and zero-point charge. The prepared nanoparticles had a rough and porous surface, and contained oxygenous (-OH, -COOH, etc.) functional groups. The specific surface area and average pore size distribution were 83 m2/g and 5.17 nm, respectively. Net zero charge on the surface of the prepared nanoparticles was observed at pH 7.5. The prepared nanoparticles were used as an adsorbent to remove methylene blue dye from water under various conditions. Using small amounts of the adsorbent (2.0 g/L), even a high concentration of MB dye (60 mg/L) could be reduced by about ~58%. Exothermic, spontaneous, feasible, and monolayer adsorption was identified based on thermodynamics and isotherm analysis. Reusability testing verified the stability of the adsorbent and found that the reused adsorbent performed well for up to three thermal cycles. Comparative analysis revealed that the modified adsorbent outperformed previously reported adsorbents and unmodified Fe2MnO4 in terms of its partition coefficient and equilibrium adsorption capacity under different experimental conditions.

Enhancing Zn (II) recovery efficiency: Bi-divalent nickel-cobalt ferrite spinel NiXCo1-xFe2O4 as a Game-changing Adsorbent-an experimental and computational study

This study presents a comprehensive investigation into NiXCo1-xFe2O4 (x = 0.5) spinel nanoparticles synthesized through a one-pot hydrothermal method using Co(NO3)2.6H2O and Ni(NO3)2.6H2O salts. XRD, FTIR, FESEM, and VSM analyses confirmed a cubic structure of NiXCo1-xFe2O4 (x = 0.5) nanoparticles without impurities. These nanoparticles exhibit efficient Zn (II) adsorption characteristics, following Langmuir isotherm and pseudo-second-order kinetics. The maximum adsorption capacity was measured to be 666.67 mg g-1 at pH = 7, with mechanisms involving both electrostatic attraction and cation exchange. Desorption studies indicate more than 75% Zn (II) recovery in an acidic environment (pH = 2) after three cycles. Computational analysis was used to validate the experimental results through Molecular Dynamics simulations, initially focusing on NiXCo1-xFe2O4 (x = 0.5). Further exploration involved variations in x at 0.25 and 0.75 to identify the optimal Ni and Co ratio in this bivalent cation spinel ferrite. Computational analyses reveal the superior performance of NiXCo1-xFe2O4 (x = 0.75) in Zn (II) removal, supported by radial distribution analysis, VdW energy, Coulombic energy, mean square displacement (MSD), root mean square displacement (RMSD), and interaction energy. This comprehensive study provides valuable insights into the adsorption behavior and structural stability of NiXCo1-xFe2O4 nanoparticles, showcasing potential applications in Zn (II) removal.

Enhanced Photocatalytic Activities of Sodium Borohydride-Calcined Magnetic Manganese Ferrite Nanoparticles

The synthesis, enhancement, and maintenance of magnetite-based catalyst nanoparticles (NPs) are important for photocatalytic activity and recovery rates. We used a sodium borohydride (NaBH4) calcination method to modify MnFe2O4 nanoparticles to optimize their performance in the photocatalytic oxidation of 2,5-hydroxymethylfurfural. The results indicated a 94% increase in photocatalytic efficiency, while magnetic assessments performed using a vibrating sample magnetometer showed an 8.9% improvement in magnetic properties without degradation. These findings show the dual benefits of increased photocatalytic performance with strong magnetic properties, which are important for the application and reusability of photocatalysts. The recycling of these photocatalysts reduces secondary pollution and increases the process cost-effectiveness. These results contribute to the solution of problems with the use of photocatalytic materials.

Zinc/Magnesium Ferrite Nanoparticles Functionalized with Silver for Optimized Photocatalytic Removal of Malachite Green

Water pollution is a major environmental challenge. Due to the inefficiency of conventional wastewater treatment plants in degrading many organic complex compounds, these recalcitrant pollutants end up in rivers, lakes, oceans and other bodies of water, affecting the environment and human health. Semiconductor photocatalysis is considered an efficient complement to conventional methods, and the use of various nanomaterials for this purpose has been widely explored, with a particular focus on improving their activity under visible light. This work focuses on developing magnetic and photoactive zinc/magnesium mixed ferrites (Zn0.5Mg0.5Fe2O4) by sol-gel and solvothermal synthesis methods, which are two of the most important and efficient methods used for the synthesis of ferrite nanoparticles. The nanoparticles (NPs) synthesized by the sol-gel method exhibited an average size of 14.7 nm, while those synthesized by the solvothermal method had an average size of 17.4 nm. Both types possessed a predominantly cubic structure and demonstrated superparamagnetic behavior, reaching a magnetization saturation value of 60.2 emu g-1. Due to the high recombination rate of electrons/holes, which is an intrinsic feature of ferrites, surface functionalization with silver was carried out to enhance charge separation. The results demonstrated a strong influence of adsorption and of the deposition of silver. Several optimization steps were performed during synthesis, allowing us to create efficient catalysts, as proved by the almost full removal of the dye malachite green attaining 95.0% (at a rate constant of 0.091 min-1) and 87.6% (at a rate constant of 0.017 min-1) using NPs obtained by the sol-gel and solvothermal methods, respectively. Adsorption in the dark accounted for 89.2% of the dye removal for nanoparticles prepared by sol-gel and 82.8% for the ones obtained by the solvothermal method. These results make mixed zinc/magnesium ferrites highly promising for potential industrial application in effluent photoremediation using visible light.

Green synthesis and characterization of polyphenol-coated magnesium-substituted manganese ferrite nanoparticles: Antibacterial and antioxidant properties

Magnesium-substituted manganese ferrite (Mn0.9Mg0.1Fe2O4) nanoparticles were obtained through a wet chemical method and coated with green-extracted polyphenol from Punica granatum peel. The obtained spinel nanocomposite was fully characterized. The X-ray diffraction pattern revealed a single phase with an average crystalline size of 3.33-8.74 nm, confirming the cubic-spinel structure. The FESEM micrograph showed a quasi-spherical shape with nearly uniform particles, indicating mild agglomeration. The mean size of the Mn0.9Mg0.1Fe2O4 was 13.66 nm with a standard deviation of 2.05. The BET isotherms indicated a surface area of 85.45 m2/g. The basic groups attached to the external surface of Mg-doped spinel ferrite were discovered. The resulted superparamagnetic modified doped-nanoferrite particles showed antibacterial activity as well as antioxidant efficiency through studying Catalase (CAT), Glutathione (GSH), and Glutathione Peroxidase (GSH-Px) parameters. The outcomes highlight the promising potential of polyphenol-functionalized Mn0.9Mg0.1Fe2O4 magnetite nanosized particles for the development of novel anti-biofilm agents.

Synthesis and Characterization of Superparamagnetic Iron Oxide Nanoparticles: A Series of Laboratory Experiments

The following laboratory procedure provides students with hands-on experience in nanomaterial chemistry and characterization. This three-day protocol is easy to follow for undergraduates with basic chemistry or materials science backgrounds and is suitable for inclusion in upper-division courses in inorganic chemistry or materials science. Students use air-free chemistry procedures to synthesize and separate iron oxide magnetic nanoparticles and subsequently modify the nanoparticle surface by using a chemical stripping agent. The morphology and chemical composition of the nanoparticles are characterized using electron microscopy and dynamic light scattering measurements. Additionally, magnetic characterization of the particles is performed using an inexpensive open-source (3D-printed) magnetophotometer. Possible modifications to the synthesis procedure, including the incorporation of dopants to modify the magnetic response and alternative characterization techniques, are discussed. The three-day synthesis, purification, and characterization laboratory will prepare students with crucial skills for advanced technology industries such as semiconductor manufacturing, nanomedicine, and green chemistry.

Evaluation of Advanced Nanomaterials for Cancer Diagnosis and Treatment

Cancer is a persistent global disease and a threat to the human species, with numerous cases reported every year. Over recent decades, a steady but slowly increasing mortality rate has been observed. While many attempts have been made using conventional methods alone as a theragnostic strategy, they have yielded very little success. Most of the shortcomings of such conventional methods can be attributed to the high demands of industrial growth and ever-increasing environmental pollution. This requires some high-tech biomedical interventions and other solutions. Thus, researchers have been compelled to explore alternative methods. This has brought much attention to nanotechnology applications, specifically magnetic nanomaterials, as the sole or conjugated theragnostic methods. The exponential growth of nanomaterials with overlapping applications in various fields is due to their potential properties, which depend on the type of synthesis route used. Either top-down or bottom-up strategies synthesize various types of NPs. The top-down only branches out to one method, i.e., physical, and the bottom-up has two methods, chemical and biological syntheses. This review highlights some synthesis techniques, the types of nanoparticle properties each technique produces, and their potential use in the biomedical field, more specifically for cancer. Despite the evident drawbacks, the success achieved in furthering nanoparticle applications to more complex cancer stages and locations is unmatched.

Synergistic potential in spinel ferrite MFe2O4 (M = Co, Ni) nanoparticles-mediated graphene oxide: Structural aspects, photocatalytic, and kinetic studies

The existence of artificial dyes in water is a significant environmental concern, as it can lead to poor water quality. Photodegradation is becoming an increasingly popular method for treating water contaminated with dyes. In this study, the photodegradation of Reactive Red 66 and Reactive Red 120 dyes, as well as textile wastewater, was investigated under UV and visible light irradiation. To enhance the photoresponse of the MFe2O4 (M = Co, Ni) nanoparticles, modifications were made by incorporating graphene oxide. The MFe2O4 nanoparticles and MFe2O4/GO nanocomposite photocatalysts were subjected to several characterization techniques, including FT-IR, Raman spectroscopy, XRD, DRS, zeta potential, VSM, TGA, DSC, BET, SEM, and EDAX analysis. Experiments were conducted to optimize several key parameters involved in the photodegradation process, including pH, photocatalyst dosage, initial dye concentration, and irradiation time. The removal efficiency of Reactive Red 66 and Reactive Red 120 dyes using CoFe2O4 nanoparticles was found to be 86.97 and 82.63%, respectively. Also, the removal percentage of these dyes using CoFe2O4/GO nanocomposite photocatalyst was 95.57 and 90.9% for Reactive Red 66 and Reactive Red 120, respectively. Experiments found that NiFe2O4 nanoparticles removed 90.92% of Reactive Red 66 dye and 84.7% of Reactive Red 120 dye. The NiFe2O4/GO nanocomposite photocatalyst showed even higher removal efficiencies, degrading 97.96% of Reactive Red 66 and 93.44% of Reactive Red 120. After three days of exposure to visible light irradiation, the removal percentage of Reactive Red 66 using MFe2O4 and MFe2O4/GO nanocomposite was investigated.

Recent applications and future prospects of magnetic biocatalysts

Magnetic biocatalysts combine magnetic properties with the catalytic activity of enzymes, achieving easy recovery and reuse in biotechnological processes. Lipases immobilized by magnetic nanoparticles dominate. This review covers an advanced bibliometric analysis and an overview of the area, elucidating research advances. Using WoS, 34,949 publications were analyzed and refined to 450. The prominent journals, countries, institutions, and authors that published the most were identified. The most cited articles showed research hotspots. The analysis of the themes and keywords identified five clusters and showed that the main field of research is associated with obtaining biofuels derived from different types of sustainable vegetable oils. The overview of magnetic biocatalysts showed that these materials are also employed in biosensors, photothermal therapy, environmental remediation, and medical applications. The industry shows a significant interest, with the number of patents increasing. Future studies should focus on immobilizing new lipases in unique materials with magnetic profiles, aiming to improve the efficiency for various biotechnological applications.

Cobalt Ferrite Synthesized Using a Biogenic Sol-Gel Method for Biomedical Applications

Cancer is one of the leading causes of death worldwide. Conventional treatments such as surgery, chemotherapy, and radiotherapy have limitations and severe side effects. Magnetic hyperthermia (MH) is an alternative method that can be used alone or in conjunction with chemotherapy or radiotherapy to treat cancer. Cobalt ferrite particles were synthesized using an innovative biogenic sol-gel method with powder of coconut water (PCW). The obtained powders were subjected to heat treatments between 500 °C and 1100 °C. Subsequently, they were characterized by thermal, structural, magnetic, and cytotoxic analyses to assess their suitability for MH applications. Through X-ray diffraction and Raman spectroscopy, it was possible to confirm the presence of the pure phase of CoFe2O4 in the sample treated at 1100 °C, exhibiting a saturation magnetization of 84 emu/g at 300 K and an average grain size of 542 nm. Furthermore, the sample treated at 1100 °C showed a specific absorption rate (SAR) of 3.91 W/g, and at concentrations equal to or below 5 mg/mL, is non-cytotoxic, being the most suitable for biomedical applications.

Development of Polymer-Encapsulated, Amine-Functionalized Zinc Ferrite Nanoparticles as MRI Contrast Agents

The need for stable and well-defined magnetic nanoparticles is constantly increasing in biomedical applications; however, their preparation remains challenging. We used two different solvothermal methods (12 h reflux and a 4 min microwave, MW) to synthesize amine-functionalized zinc ferrite (ZnFe2O4-NH2) superparamagnetic nanoparticles. The morphological features of the two ferrite samples were the same, but the average particle size was slightly larger in the case of MW activation: 47 ± 14 nm (Refl.) vs. 63 ± 20 nm (MW). Phase identification measurements confirmed the exclusive presence of zinc ferrite with virtually the same magnetic properties. The Refl. samples had a zeta potential of -23.8 ± 4.4 mV, in contrast to the +7.6 ± 6.8 mV measured for the MW sample. To overcome stability problems in the colloidal phase, the ferrite nanoparticles were embedded in polyvinylpyrrolidone and could be easily redispersed in water. Two PVP-coated zinc ferrite samples were administered (1 mg/mL ZnFe2O4) in X BalbC mice and were compared as contrast agents in magnetic resonance imaging (MRI). After determining the r1/r2 ratio, the samples were compared to other commercially available contrast agents. Consistent with other SPION nanoparticles, our sample exhibits a concentrated presence in the hepatic region of the animals, with comparable biodistribution and pharmacokinetics suspected. Moreover, a small dose of 1.3 mg/body weight kg was found to be sufficient for effective imaging. It should also be noted that no toxic side effects were observed, making ZnFe2O4-NH2 advantageous for pharmaceutical formulations.

Simplified Synthesis of the Amine-Functionalized Magnesium Ferrite Magnetic Nanoparticles and Their Application in DNA Purification Method

For pathogens identification, the PCR test is a widely used method, which requires the isolation of nucleic acids from different samples. This extraction can be based on the principle of magnetic separation. In our work, amine-functionalized magnesium ferrite nanoparticles were synthesized for this application by the coprecipitation of ethanolamine in ethylene glycol from Mg(II) and Fe(II) precursors. The conventional synthesis method involves a reaction time of 12 h (MgFe2O4-H&R MNP); however, in our modified method, the reaction time could be significantly reduced to only 4 min by microwave-assisted synthesis (MgFe2O4-MW MNP). A comparison was made between the amine-functionalized MgFe2O4 samples prepared by two methods in terms of the DNA-binding capacity. The experimental results showed that the two types of amine-functionalized magnesium ferrite magnetic nanoparticles (MNPs) were equally effective in terms of their DNA extraction yield. Moreover, by using a few minutes-long microwave synthesis, we obtained the same quality magnesium ferrite particles as those made through the long and energy-intensive 12-h production method. This advancement has the potential to improve and expedite pathogen identification processes, helping to better prevent the spread of epidemics.

Crystal structure and peculiarities of microwave parameters of Co1-xNixFe2O4 nano spinel ferrites

Nanosized spinel ferrites Co1-xNixFe2O4 (where x = 0.0-1.0) or CNFO have been produced using a chemical method. The crystal structure's characteristics have been determined through the utilization of X-ray diffraction (XRD). It has been demonstrated that all samples have a single phase with cubic syngony (space group Fd3̄m). The lattice parameter and unit cell volume behavior correlate well with the average ionic radii of Co2+ and Ni2+ ions and their coordination numbers. Thus, an increase in the Ni2+ content from x = 0.0 to x = 1.0 leads to a decrease in the lattice parameter (from 8.3805 to 8.3316 Å) and unit cell volume (from 58.86 to 57.83 Å3). Elastic properties have been investigated using Fourier transform infrared (FTIR) analysis. The peculiarities of the microwave properties have been analyzed by the measured S-parameters in the range of 8-18 GHz. It was assumed that the energy losses due to reflection are a combination of electrical and magnetic losses due to polarization processes (dipole polarization) and magnetization reversal processes in the region of inter-resonant processes. A significant attenuation of the reflected wave energy (-10 … -21.8 dB) opens broad prospects for practical applications.

Efficacy of Carbon Nanodots and Manganese Ferrite (MnFe2O4) Nanoparticles in Stimulating Growth and Antioxidant Activity in Drought-Stressed Maize Inbred Lines

Despite being the third most-consumed crop, maize (Zea mays L.) is highly vulnerable to drought stress. The predominant secondary metabolite in plants is phenolic acids, which scavenge reactive oxygen species to minimize oxidative stress under drought stress. Herein, the effect of carbon nanodots (CND) and manganese ferrite (MnFe2O4) nanoparticles (NP) on the drought stress tolerance of maize has been studied. The experimental results revealed that the highest leaf blade length (54.0 cm) and width (3.9 cm), root length (45.2 cm), stem diameter (11.1 mm), root fresh weight (7.0 g), leaf relative water content (84.8%) and chlorogenic (8.7 µg/mL), caffeic (3.0 µg/mL) and syringic acid (1.0 µg/mL) contents were demonstrated by CND-treated (10 mg L-1) inbred lines (GP5, HW19, HCW2, 17YS6032, HCW3, HCW4, HW7, HCW2, and 16S8068-9, respectively). However, the highest shoot length (71.5 cm), leaf moisture content (83.9%), shoot fresh weight (12.5 g), chlorophyll content (47.3), and DPPH free radical scavenging activity (34.1%) were observed in MnFe2O4 NP-treated (300 mg L-1) HF12, HW15, 11BS8016-7, HW15, HW12, and KW7 lines, respectively. The results indicate that CND and MnFe2O4 NP can mitigate drought stress effects on different accessions of the given population, as corroborated by improvements in growth and physio-biochemical traits among several inbred lines of maize.