Manganese Ferrite Nanoparticles Research Articles

High Specific Absorption Rate and Transverse Relaxivity Effects in Manganese Ferrite Nanoparticles Obtained by an Electrochemical Route

Superparamagnetic iron oxide-based nanoparticles (SPIONS) have attracted an enormous amount of attention for their potential use in biomedical applications, due to their good biocompatibility and low toxicity. The current study considers citric acid-conjugated manganese ferrite and its synergy to be used in MRI and in hyperthermia treatment, thus showing theragnostic applications. High colloidal stability was obtained with this functionalization. SPIONS with superparamagnetic behavior of crystal sizes of approximately 20 nm were obtained via an electrochemical synthesis method. One of the highest specific absorption rate (SAR) values was achieved in this work (1661 W g–1), under a magnetic field of 30 mT at 717 kHz frequency, compared with other magnetic ferrites in the literature. These nanoparticles dissipate heat through Néel relaxation and, together with the high SAR value obtained, indicate an excellent material for hyperthermia treatment of cancer. In addition, these nanoparticles exhibit transverse relaxivity behavior, with an r2 value of 394 mM–1 s–1, i.e., at least two times higher than the value of a commercial magnetic contrast agent based on iron oxides. Finally, no toxicity effects of these nanoparticles are evidenced; as a result, these nanoparticles are appropriate for in vivo application.

ChemInform Abstract: Manganese Ferrite Nanoparticle Catalyzed Tandem and Green Synthesis of Spirooxindoles.

AbstractA novel one‐pot three‐component reaction of isatins, anilinolactones, and malonitrile furnishes spirooxindoles with potential biological activity.

Modified magnetic properties of MnFe2O4 by CTAB with coprecipitation method

Manganese ferrite (MnFe2O4) nanoparticles (NPs) were synthesized by a coprecipitation method, in which an organic alkali, 1-amino-2-propanol (MIPA), was used. The effects of hexadecyl (trimethyl) azanium bromide (CTAB) on magnetic properties of the as-synthesized MnFe2O4 NPs were studied. The saturation magnetization (Ms) is increasing with the concentration of CTAB to 0.5mM, and it decreases when the concentration of CTAB further increased to 1.0mM, where the maximum Ms of the sample is 54.5emu/g. The effects of CTAB on the crystal size and particle size for these samples were studied, which were used to explain the Ms differences of these samples. At the same time, the crystallization and the adsorption of CTAB on the samples may also affect the magnetic property of the sample.

Water oxidation catalysis by birnessite@iron oxide core-shell nanocomposites.

In this work, magnetic nanocomposite particles were prepared for water oxidation reactions. The studied catalysts consist of maghemite (γ-Fe2O3), magnetite (Fe3O4), and manganese ferrite (MnFe2O4) nanoparticles as cores coated in situ with birnessite-type manganese oxide shells and were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermal, chemical, and surface analyses, and magnetic measurements. The particles were found to be of nearly spherical core-shell architectures with average diameter of 150 nm. Water oxidation catalysis was examined using Ce(4+) as the sacrificial oxidant. All core-shell particles were found to be active water oxidation catalysts. However, the activity was found to depend on a variety of factors like the type of iron oxide core, the structure and composition of the shell, the coating characteristics, and the surface properties. Catalysts containing magnetite and manganese ferrite as core materials displayed higher catalytic activities per manganese ion (2650 or 3150 mmolO2 molMn(-1) h(-1)) or per mass than nanoiron oxides (no activity) or birnessite alone (1850 mmolO2 molMn(-1) h(-1)). This indicates synergistic effects between the MnOx shell and the FeOx core of the composites and proves the potential of the presented core-shell approach for further catalyst optimization. Additionally, the FeOx cores of the particles allow magnetic recovery of the catalyst and might also be beneficial for applications in water-oxidizing anodes because the incorporation of iron might enhance the overall conductivity of the material.

Synthesis and Characterization of Metal (Mn,Zn) Ferrite Magnetic Nanoparticles

Zinc ferrite (ZnFe2O4) and Manganese ferrite (MnFe2O4) nanoparticles were prepared by the chemical co-precipitation method and calcinated at 8000C for 5hrs. The results of XRD and SEM show that sample product was crystalline with mixed type spinel with cubic structure. The FT-IR spectrum shows most intense absorption bands 464 cm-1 and 550 cm-1 due to the strong transition metal stretching. Uv-vis studies reveal the band gap energy variation between different metal substitutions in the synthesis. Coercivity of ZnFe2O4 and MnFe2O4 nanoparticles was calculated using VSM studies is in the range of 14.456 G and 50.495 G respectively.

Long-circulating PEGylated manganese ferrite nanoparticles for MRI-based molecular imaging.

Magnetic resonance based molecular imaging has emerged as a very promising technique for early detection and treatment of a wide variety of diseases, including cancer, neurodegenerative disorders, and vascular diseases. The limited sensitivity and specificity of conventional MRI are being overcome by the development of a new generation of contrast agents, using nanotechnology approaches, with improved magnetic and biological properties. In particular, for molecular imaging, high specificity, high sensitivity, and long blood circulation times are required. Furthermore, the lack of toxicity and immunogenicity together with low-cost scalable production are also necessary to get them into the clinics. In this work, we describe a facile, robust and cost-effective ligand-exchange method to synthesize dual T1 and T2 MRI contrast agents with long circulation times. These contrast agents are based on manganese ferrite nanoparticles (MNPs) between 6 and 14 nm in size covered by a 3 kDa polyethylene glycol (PEG) shell that leads to a great stability in aqueous media with high crystallinity and magnetization values, thus retaining the magnetic properties of the uncovered MNPs. Moreover, the PEGylated MNPs have shown different relaxivities depending on their size and the magnetic field applied. Thus, the 6 nm PEGylated MNPs are characterized by a low r2/r1 ratio of 4.9 at 1.5 T, hence resulting in good dual T1 and T2 contrast agents under low magnetic fields, whereas the 14 nm MNPs behave as excellent T2 contrast agents under high magnetic fields (r2 = 335.6 mM(-1) s(-1)). The polymer core shell of the PEGylated MNPs minimizes their cytotoxicity, and allows long blood circulation times. This combination of cellular compatibility and excellent T2 and r2/r1 values under low magnetic fields, together with long circulation times, make these nanomaterials very promising contrast agents for molecular imaging.

Withdrawn: Chemical co-precipitation synthesis of spinel manganese ferrite nanoparticles (MnFe2O4): Morphological characterizations and magnetic properties

Withdrawn: Chemical co-precipitation synthesis of spinel manganese ferrite nanoparticles (MnFe2O4): Morphological characterizations and magnetic properties

Imidazolized magnetic nanovectors with endosome disrupting moieties for the intracellular delivery and imaging of siRNA.

The development of a synchronized delivery and imaging system for small interfering RNA (siRNA) is required for the clinical application of RNA interference (RNAi) in cancer treatment. Herein, we report a pH-responsive, magnetic nanoparticle-based siRNA delivery system that can facilitate the safe and efficient delivery and visualization of therapeutic siRNA by high-resolution magnetic resonance (MR) imaging. Cationic poly-l-lysine-graft-imidazole (PLI) with a reactive silane moiety was stably immobilized onto the surface of the assembled manganese ferrite nanoparticles (MFs) through an emulsion process, ensuring high water solubility, enhanced MR contrast effect, and endosome-disrupting functionality. The synthesized nanovectors were then complexed with siRNA targeting the CD44 gene via electrostatic interactions to verify the specific gene-silencing effect. The imidazolized magnetic nanovector (ImMNV) architectures developed here facilitated improved cellular internalization and exhibited a high level in vitro downregulation compared to non-imidazolized MNVs in metastatic breast cancer cells.

Graphene oxide-MnFe2O4 magnetic nanohybrids for efficient removal of lead and arsenic from water.

We show that the hybrids of single-layer graphene oxide with manganese ferrite magnetic nanoparticles have the best adsorption properties for efficient removal of Pb(II), As(III), and As(V) from contaminated water. The nanohybrids prepared by coprecipitation technique were characterized using atomic force and scanning electron microscopies, Fourier transformed infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and surface area measurements. Magnetic character of the nanohybrids was ascertained by a vibrating sample magnetometer. Batch experiments were carried out to quantify the adsorption kinetics and adsorption capacities of the nanohybrids and compared with the bare nanoparticles of MnFe2O4. The adsorption data from our experiments fit the Langmuir isotherm, yielding the maximum adsorption capacity higher than the reported values so far. Temperature-dependent adsorption studies have been done to estimate the free energy and enthalpy of adsorption. Reusability, ease of magnetic separation, high removal efficiency, high surface area, and fast kinetics make these nanohybrids very attractive candidates for low-cost adsorbents for the effective coremoval of heavy metals from contaminated water.

Laccase immobilized manganese ferrite nanoparticle: Synthesis and LSSVM intelligent modeling of decolorization

Laccase was immobilized onto manganese ferrite nanoparticle (MFN) and dye decolorization from single and binary systems was studied. The characteristics of laccase immobilized manganese ferrite nanoparticle (LIMFN) were investigated using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Direct red 31 (DR31), Acid blue 92 (AB92) and Direct green 6 (DG6) were used. A least square support vector machine (LSSVM) was developed to predict the decolorization efficiency of various single and binary systems based on the obtained laboratory data under different experimental conditions. Statistical and graphical quality measures were also employed to evaluate the performance and accuracy of the developed intelligent models. It is shown that the predictions of the designed LSSVM models are in close agreement with the experimental data. The effects of LIMFN dosage, pH and dye concentration on dye decolorization from single and binary systems were evaluated. Decolorization kinetics followed Michaelis–Menten Model.

MnFe2O4@NH2@2AB-Ni: a novel, highly active, stable and magnetically recoverable nanocatalyst and use of this heterogeneous catalyst in green synthesis of spirooxindoles in water

In this research, superparamagnetic manganese ferrite nanoparticles were synthesized following a co-precipitation method, and subsequently coated with 3-aminopropyltriethoxysilane (APTES) through a silanization reaction. Manganese ferrite nanoparticles afforded bidentate ligands as a result of the reaction between isatoic anhydride and amino-functionalized MnFe2O4. The amino-functionalized nanoparticles were treated with nickel acetate, giving the immobilized nickel complex. Finally, catalytic properties of the prepared nanoparticles were examined by a green synthesis of spirooxindoles in water and they showed excellent catalytic activity. Recovery of the catalyst was simply achieved by applying an external permanent magnet. The isolated catalyst was reused for new reaction runs without significant loss of catalytic activity.

Effect of pH and annealing temperatures on structural, magnetic, electrical, dielectric and adsorption properties of manganese ferrite nano particles

Manganese ferrite (MnFe2O4) samples of good homogeneity were synthesized at pH 8 and pH 11 for different annealing temperatures through wet chemical synthesis by a co-precipitation method. Particle size increases and crystalline nature improved with increase in annealing temperatures as indicated in XRD peaks. EDS study confirmed the purity of the prepared samples. The cubic spinel structure and bond stretching of samples were analyzed through FTIR. The surface studies were carried out using SEM micrographs. The SAED patterns predicted crystalline nature and the particle size was found to be 20–40nm as confirmed through TEM analysis. The magnetic hysteresis curves were analyzed using VSM and super paramagnetic nature of soft magnetic material was reported for samples prepared at pH 8. The dielectric and conductivity studies confirm that the material can be used in high frequency applications. The application of the synthesized ferrite as adsorbent of toxic heavy metal Cr(VI) has been successfully tested. The adsorption and removal depend on quantity of adsorbent, annealing temperatures of sample, pH of sample and initial concentration of Cr(VI).

Effect of cobalt substitution on structural and magnetic properties and chromium adsorption of manganese ferrite nano particles

Manganese ferrite (MnFe2O4) and cobalt doped manganese ferrite (Mn1−xCoxFe2O4) with x=0, 0.2, 0.4, 0.6, and 0.8 are synthesized at pH 11 and an annealing temperature of 900°C, through co-precipitation technique. The particle sizes are found to be in the range of 30–35nm. The varying dopant concentrations influence the crystalline edges, surface morphology and magnetic properties of the samples. Particle size initially increases for the incorporation of cobalt up to x=0.6 and then decreases. As cobalt concentration increases, the saturation magnetization increases up to x=0.6 and then decreases. Stretching and bending of bonds at tetrahedral and octahedral sites respectively are noticed and they shift towards the longer wavelengths. The samples are tested for their application as adsorbents of toxic heavy metal Cr(VI). The adsorption efficiency variations with dopant concentrations of samples, quantity of adsorbent and concentrations of chromium are studied.

Surface modification and ternary system dye removal ability of manganese ferrite nanoparticle

In this paper, the surface of magnetic manganese ferrite nanoparticles (MFN) was modified using cetyl trimethylammonium bromide (CTAB). The modified MFN was studied using Fourier transform infrared spectroscopy (FTIR). The adsorption capacity of surface modified MFN (MFN-CTAB) was investigated for dye removal for single and ternary systems. Three anionic dyes, C.I. Direct Red 80 (DR80), C.I. Direct Red 31 (DR31), and C.I. Acid Blue 92 (AB92), were used as model compounds. The effects of operational parameters on dye removal (i.e. adsorbent dosage, dye concentration and salt) and the kinetic and isotherm of dye adsorption were studied. The adsorption kinetic for the dyes was found to be well described by the pseudo-second order model. The maximum dye adsorption capacity (Q 0) of MFN-CTAB for DR80, DR31 and AB92 was 83 mg/g, 59 mg/g and 70 mg/g, respectively. The adsorption isotherm data were analyzed using the Langmuir, Freundlich, and Temkin equations. The results revealed that the Langmuir model fitted the adsorption data better. The results showed that the MFN-CTAB as a magnetic adsorbent might be a suitable alternative to remove dyes from colored aqueous solutions.

A direct synthesis of water soluble monodisperse cobalt and manganese ferrite nanoparticles from iron based pivalate clusters by the hot injection thermolysis method

Highly monodisperse water soluble cobalt ferrite (CoFe2O4) and manganese ferrite (MnFe2O4) nanoparticles were synthesised by the hot injection thermolysis of pivalate clusters as single source precursors. The precursors [Fe2CoO(O2CtBu)6(HO2CtBu)3] (1) and [Fe2MnO(O2CtBu)6(HO2CtBu)3] (2) were decomposed in a mixture of polyvinylpyrrolidone (PVP) (capping agent) and triethylene glycol (TREG) (solvent) at 285°C to produce cobalt ferrite and manganese ferrite nanoparticles, respectively. The effect of the PVP on the size and morphology of the nanoparticles synthesised was investigated. Smaller sized nanoparticles of cobalt and manganese ferrite nanoparticles were obtained at higher PVP concentration and larger nanoparticles were produced at lower PVP concentrations. The ferrite nanoparticles produced are monodisperse, directly dispersible in water without any further size selection/postsynthesis procedure. The nanoparticles were characterised by powder X-ray diffraction (p-XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS) and selected area electron diffraction (SAED).

Influence of Zinc on the Structure and Morphology of Manganese Ferrite Nanoparticles

Nanocrystalline spinel ferrites with general formula of MnxZn1−xFe2O4; x = 1.0, 0.8, 0.6, 0.4, 0.2, 0.1 were prepared via co-precipitation method at 75 °C and pH 11. The XRD results showed that the doping of Zn ions into ferrite’s structure resulted in the reduction of both crystallinity and crystallite size. The results also revealed that the synthesized MnxZn1−xFe2O4 crystalline in spinel cubic structure with particle size range of 13.0 – 22.5 nm. Field emission scanning electron microscopy (FESEM) images showed an increase in particle size with the decreasing Zn content. The types of chemical covalent bonds which existed in the samples were determined via Fourier transforms infrared (FTIR) spectroscopy.

Biocompatible mesoporous silica-coated superparamagnetic manganese ferrite nanoparticles for targeted drug delivery and MR imaging applications

Multifunctional mesoporous silica-coated superparamagnetic manganese ferrite (MnFe2O4) nanoparticles (M-MSN) were synthesized and evaluated for targeted drug delivery and magnetic resonance imaging (MRI) applications. MnFe2O4 nanoparticles were prepared by solvothermal route and were silica-coated by surface silylation using sol–gel reactions. Subsequently, silylation was done using (3-aminopropyl)triethoxysilane in presence of a surfactant (CTAB), followed by selective etching of the surfactant molecules that resulted in amine-functionalized superparamagnetic nanoparticles (NH2-MSN). Further modification of the surface of the NH2-MSN with targeting (folate) or fluorescent (RITC) molecules resulted in M-MSN. The formation of the M-MSN was proved by several characterization techniques viz. XRD, XPS, HRTEM, FESEM, VSM, BET surface area measurement, FTIR, and UV–Vis spectroscopy. The M-MSN were loaded with anticancer drug Doxorubicin and the efficacy of the DOX loaded M-MSN was evaluated through in vitro cytotoxicity, fluorescence microscopy, and apoptosis studies. The in vivo biocompatibility of the M-MSN was demonstrated in a mice-model system. Moreover, the M-MSN also acted as superior MRI contrast agent owing to a high magnetization value as well as superparamagnetic behavior at room temperature. These folate-conjugated nanoparticles (FA-MSN) exhibited stronger T2-weighted MRI contrast towards HeLa cells as compared to the nanoparticles without folate conjugation, justifying their potential importance in MRI based diagnosis of cancer. Such M-MSN with a magnetic core required for MRI imaging, a porous shell for carrying drug molecules, a targeting moeity for cancer cell specificity and a fluorescent molecule for imaging, all integrated into a single system, may potentially serve as an excellent material in biomedical applications.

ChemInform Abstract: Efficient Synthesis of Novel Spiro‐Furo‐Pyrido‐Pyrimidine‐Indolines by Manganese Ferrite Nanoparticles as a Highly Active Magnetically Reusable Nanocatalyst in Water.

AbstractThe manganese ferrite nanoparticles can be easily separated using an external magnet and retain their catalytic activity for at least five repeated uses.

Biodistribution and acute toxicity of a nanofluid containing manganese iron oxide nanoparticles produced by a mechanochemical process.

Superparamagnetic iron oxide nanoparticles are candidate contrast agents for magnetic resonance imaging and targeted drug delivery. Biodistribution and toxicity assessment are critical for the development of nanoparticle-based drugs, because of nanoparticle-enhanced biological reactivity. Here, we investigated the uptake, in vivo biodistribution, and in vitro and in vivo potential toxicity of manganese ferrite (MnFe2O4) nanoparticles, synthesized by an original high-yield, low-cost mechanochemical process. Cultures of murine Balb/3T3 fibroblasts were exposed for 24, 48, or 72 hours to increasing ferrofluid concentrations. Nanoparticle cellular uptake was assessed by flow-cytometry scatter-light measurements and microscopy imaging after Prussian blue staining; cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony-forming assays. After a single intravenous injection, in vivo nanoparticle biodistribution and clearance were evaluated in mice by Mn spectrophotometric determination and Prussian blue staining in the liver, kidneys, spleen, and brain at different posttreatment times up to 21 days. The same organs were analyzed for any possible histopathological change. The in vitro study demonstrated dose-dependent nanoparticle uptake and statistically significant cytotoxic effects from a concentration of 50 μg/mL for the MTT assay and 20 μg/mL for the colony-forming assay. Significant increases in Mn concentrations were detected in all analyzed organs, peaking at 6 hours after injection and then gradually declining. Clearance appeared complete at 7 days in the kidneys, spleen, and brain, whereas in the liver Mn levels remained statistically higher than in vehicle-treated mice up to 3 weeks postinjection. No evidence of irreversible histopathological damage to any of the tested organs was observed. A comparison of the lowest in vitro toxic concentration with the intravenously injected dose and the administered dose of other ferrofluid drugs currently in clinical practice suggests that there might be sufficient safety margins for further development of our formulation.

Synthesized Magnetic Manganese Ferrite Nanoparticles on Activated Carbon for Sulfamethoxazole Removal

The presence of pharmaceutical compounds in water has adverse environmental and health impacts. The main objective of the current research are to investigate the removal efficiency of sulfamethoxazole (SMX) from aqueous solution by using magnetic manganese ferrite nanoparticles synthesized on powdered activated carbon (PAC). Magnetic activated carbon composites (MACC) were prepared by using chemical co‐precipitation at different temperature values ranging from 298 to 423 K. The obtained samples were characterized by contemporary characterization instrumental methods of analysis, and their SMX removal capabilities were evaluated. Results revealed that the procedure successfully created magnetic nanoparticles on PAC at temperatures of 298–423 K, and the anchored MnFe2O4/MnO2 manifested more crystalline forms at 423 K. As a result, MACC prepared at 423 K showed the highest magnetic and sorption capacities among three obtained samples. The SMX maximal adsorption capacity of MACC(423K) was 159 mg/g at pH 7, and the SMX adsorption remained stable at pH 3–7. The effect of common ions and humic acids on SMX adsorption indicates a high selectivity of MACC(423K) for SMX. Furthermore, MACC(423K) achieved much higher regeneration efficiency by H2O2 than that of virgin PAC, due to the presence of MnFe2O4/MnO2.