Fe3O4 Magnetite Nanoparticles Research Articles

PAN—Composite Electrospun-Fibers Decorated with Magnetite Nanoparticles

The results of the synthesis of PAN(polyacrylonitrile)-magnetite composite fibers using the electrospinning method are presented. The electrospinning installation included a rotating drum collector for collecting fibers. Magnetite nanoparticles were synthesized using chemical condensation from an iron chloride solution. It was shown that homogeneous Fe3O4 magnetite nanoparticles with particle sizes of 6–16 nm could be synthesized using this method. Magnetite nanoparticles were investigated using X-ray diffraction analyses and transmission electron microscopy. Based on magnetite nanoparticles, composite PAN/magnetite fibers were obtained through electrospinning. The obtained composite fibers were investigated using scanning electron microscopy, X-ray diffraction analyses, and elemental analyses. It was shown that the magnetite nanoparticles were uniformly distributed on the surface of the fibers. A comparison of PAN fibers without any added magnetite to PAN/magnetite fibers showed that the addition of magnetite led to a decrease in the value of the fiber diameter at the same polymer concentration and under the same electrospinning process conditions.

Influence of synthesis conditions on the structure and size of magnetite nanoparticles in coprecipitation method without stabilizer in one system

The unique properties of magnetite (Fe3O4) nanoparticles (MNPs) have promoted a wide range of applications in various fields, but specifying and defining the preparation conditions of MNPs with the desired monodispersed size are still challenges. This paper discusses systematically the influence of synthesis conditions on the structure and size of MNPs in the coprecipitation method without a stabilizer in one system. The ammonium hydroxide (NH4OH)/iron (III) (Fe3+) ratio, iron (III)/iron (II) (Fe2+) ratio, initial concentration of hydrochloric acid (HCl), total concentration of iron ions, reaction temperature, aging time and washing times were investigated. The surface of magnetite crystals was easily oxidized at high ammonium hydroxide/iron (III) ratios, and the high pH value of the reaction system can induce a large crystalline size. The hydrodynamic diameter of MNPs was efficiently controlled by the equilibrium between Derjaguin–Landau–Verwey–Overbeek (DLVO) forces and non-DLVO forces. An appropriate initial concentration of hydrochloric acid and a higher reaction temperature can reduce the crystalline size due to the decelerated nucleation rate. The aging time and the total concentration of iron affected the crystalline size positively. Noticeably, the pH value of the MNP dispersion in distilled water would remarkably reduce after each washing by centrifugation due to surface absorption of the hydroxy group. This research provided fundamental support for the reproducible preparation of MNPs in the coprecipitation method.

Synthesis of Fe3O4/CNT/ACF cathode-based electro-fenton system for efficient mineralization of methylene blue dye: Kinetics and mechanism

Electro-Fenton (EF) is an innovative process to use in situ generated H2O2 and ∙OH to destruct organic contaminants in wastewater. In this study, methylene blue (MB) was degraded using activated-carbon-felt (ACF) composite cathodes (CNT/ACF, Fe3O4/ACF, and Fe3O4/CNT/ACF). Magnetite (Fe3O4) nanoparticles (MNPs) and carbon nanotubes (CNTs) were used as surface modifiers, i.e., Fe3O4, to facilitate easy charge-transfer by forming multilayered channels and CNTs to enhance the thermal and structural strength of the electrode. When Fe3O4/CNT/ACF was used as cathode, the removal efficiency of 93.7% for MB could be obtained within 1 h; the MB degradation followed the pseudo-second-order kinetics with the rate constant of 2.73 × 10−2 M−1 min−1. Based on total organic carbon (TOC) analysis, 57.8% of MB could be mineralized by the cathode system, which was also confirmed by evaluating the mineralization current efficiency (MCE, kWh m–3). When the EF oxidation time was raised to 2.5 h, MB could be completely degraded while mineralization efficiency was 87%. At 2.5-h degradation time, Fe3O4/CNT/ACF exhibited the highest removal efficiency for color and TOC among the three synthesized electrodes, proving that the cathode has an outstanding catalytic oxidation power for MB degradation with high stability. Thus, the overall study provides an insight for an innovative mechanism of integrating well-performing and easily recyclable electrode composites in an EF system for treating recalcitrant organic pollutants existing in wastewater.

Green synthesis of NiO/Fe3O4@chitosan composite catalyst based on graphite for urea electro-oxidation

In this work, we modified the NiO-based graphite electrode by a green synthesis nanoparticles composite of magnetite@chitosan for urea electrooxidation (UEO) in 0.5 M KOH solution. Green magnetite (Fe3O4) nanoparticles were prepared with green tea extract that acts as a reducing agent. The new composite catalyst Fe3O4@Chitosan performs a dual function to improve the catalytic properties of UEO. The magnetite Fe3O4 nanoparticles increase the active sites by accelerating the electron transfer between Fe3+/Fe2+ions, while chitosan enhances urea adsorption on the electrode surface. Three graphite electrodes were prepared with different NiO and Fe3O4@Chitosan catalysts ratios under optimized conditions and denoted by Ni0.85Fe0.15, Ni0.75Fe0.25, and Ni0.65Fe0.35. The excellent catalytic parameters as maximum current density (35.4 mA cm−2), Tafel slope (69 mVdec−1), diffusion coefficient (5.759 × 10−6 cm2 s−1), and onset potential (446 mV vs. Ag/AgCl) were achieved by Ni0.75Fe0.25 electrocatalyst. The modified NiO/Fe3O4@chitosan electrocatalyst was characterized by XRD and SEM/EDEX-elemental mapping techniques characterized its morphology and chemical structures. Moreover, cyclic voltammetry, double-step Choronoamerometery, and electrochemical impedance were employed to detect the electrodes' catalytic performance. The EIS fitting parameters deduced from R(RQ)& (RQ) equivalent circuits were used to explain how the Ni/Fe ratios' can affect the charge transfer process of UOR at the prepared electrocatalysts surfaces under the applied potentials.

Improvement in desulfurization of dibenzothiophene and dibenzothiophene sulfone by Paenibacillus strains using immobilization or nanoparticle coating.

Biodesulfurization of fossil fuels is a promising technology for deep desulfurization. Previously, we have shown that Paenibacillus strains 32O-W and 32O-Y can desulfurize dibenzothiophene (DBT) and DBT sulfone (DBTS) effectively. In this work, improvements in DBT and DBTS desulfurization by these strains were investigated through immobilization and nanoparticle coating of cells. Paenibacillus strains 32O-W and 32O-Y immobilized in alginate gel beads or coated with Fe3 O4 magnetite nanoparticles were grown at various concentrations (0.1-2 mmol l-1 ) of DBT or DBTS for 96 h. The production of 2-hydroxybiphenyl (2-HBP) from the 4S pathway biotransformation of DBT or DBTS was measured. The highest amounts of 2-HBP production occurred at concentrations of 0.1 and 0.5 mmol l-1 . Compared to planktonic cultures maximum 2-HBP production increased by 54% for DBT and 90% for DBTS desulfurization with immobilized strains, and 44% for DBT and 66% for DBTS desulfurization by nanoparticle-coated strains. Nanoparticle-coated and immobilized cells may be of use in efforts to increase the efficiency of biodesulfurization. Alginate immobilization or nanoparticle coating of bacterial cells may be useful approaches for the enhancement of biodesulfurization for eventual use on an industrial scale.

Conductive magnetite nanoparticles considerably accelerated carbon steel corrosion by electroactive Desulfovibrio vulgaris biofilm

Carbon steel microbiologically influenced corrosion (MIC) by sulfate reducing Desulfovibrio vulgaris belongs to extracellular electron transfer MIC (EET-MIC). Adding 20 ppm (w/w) Fe3O4 magnetite nanoparticles (MNPs) to ATCC 1249 culture medium did not alter sessile and planktonic cell counts significantly, but it caused 59% more weight loss and 85% deeper pit depth, respectively after 7 days of incubation. Electrochemical data corroborated the increases. In comparison, D. vulgaris MIC of Cu was not affected by 20 ppm MNPs because it belongs to metabolite MIC (M-MIC) without EET. Thus, MNPs can be a useful tool to distinguish some EET-MIC cases from M-MIC.

Preparation and spectral studies of boronate ester modified magnetite iron nanoparticles (Fe3O4@APTES-B) as a new type of biological agents

We have designed two novel magnetite targeting biological agents (Fe3O4@APTES-B(1,2)) with a core of Fe3O4 and a shell made of boronate esters (APTES-B) to improve the biological effectiveness of magnetite Fe3O4 nanoparticles (MNPs). Initially, two boronate esters (B1) and (B2) have been prepared by 3,4-dihydroxybenzaldehyde and phenylboronic acid and/or butylboronic acid using a Dean-Stark apparatus to remove the water formed during the esterification reactions. Then, the APTES-B1,2 compounds have been synthesized via boronate esters and APTES in the presence of 1–2 drops of formic acid as catalyst. Finally, magnetite Fe3O4 NPs were added to APTES-B1,2 compounds to afford boronate ester modified magnetite iron nanoparticles (Fe3O4@APTES-B1,2) at ambient temperature, respectively. The boronate esters (B1) and (B2), APTES-B1,2 compounds, and boronate ester modified magnetite iron nanoparticles (Fe3O4@APTES-B1,2) were characterized using a combination of NMR (1H, 13C, and 11B), FT-IR, UV–Vis, LC-MS/MS, elemental analysis (CHN), XRD, SEM-EDX, EDX mapping, BET, and TG-DTA). Then, the antioxidant, antimicrobial and DNA binding activities of newly synthesized target compounds were tested. These results suggest that all compounds are also one of the propitious drug candidates and are worthy of further investigation.

High-pressure neutron diffraction study of magnetite, Fe3O4, nanoparticles

We use in situ high-pressure neutron powder diffraction to study elastic properties of Fe3O4 magnetite nanoparticles of different sizes. It is found that nanoparticles are elastically softer than the bulk. Apart from the smallest nanoparticle of diameter 8 nm, the atomic and magnetic structures do not change significantly with nanoparticle size or pressure. The 8 nm sample appears to take a disordered spinel structure instead of the inverse spinel structure of the bulk and larger nanoparticles, as seen in bond lengths and magnetic structures. Synchrotron x-ray total scattering was used to support this interpretation. Furthermore, this study suggests that the influence of magnetic disorder at the nanoparticle surface is significant for the size of 8 nm.

A biocatalytic system obtained via immobilization of urease onto magnetic metal/alginate nanocomposite: Improving reusability and enhancing stability

Alginate is a biomaterial that is considered suitable for enzyme immobilization. The biocompatibility and characteristics of the immobilized system can be improved by combining alginate with magnetite Fe3O4 nanoparticles. Therefore, the current study investigated the effect of magnetite Fe3O4 NPs on urease immobilization using different concentrations of magnetite Fe3O4 NPs. The morphological features for alginate/magnetite Fe3O4 NPs before and after immobilization were studied using an SEM, TGA, and FTIR. The reusability, half-life, enzymatic kinetics, and storage stability of the enzyme were all enhanced. The immobilization efficiency was determined to be 91% at optimal conditions. The immobilized urease was reused 20 times and a recovery of 59% of the initial activity. The soluble and immobilized urease was stored at 4 °C for 12 weeks and preserved 13% and 49% of the initial activities, respectively. The optimum pH for soluble and immobilized urease activity was estimated to be 7. The optimum temperature for soluble and immobilized urease activity was found to be 35 °C and 40 °C, respectively. The kinetics parameters showed the Vmax of 4.4 and 3.1 μmol/ml·min and the Km of 49.5 and 54.6 mM for the soluble and immobilized urease, respectively. Immobilized urease had a half-life of 11–20 min. The activation energy (Ea) of immobilized urease was determined to be 32 kJ K−1 mol−1, indicating that a small quantity of energy is required to produce the activated complex of substrate hydrolysis.

Physico-magnetic properties and dynamics of magnetite (Fe3O4) nanoparticles (MNPs) under the effect of permanent magnetic fields in contaminated water treatment applications

In this work, a modelling and experimental study was performed to understand the dynamic behaviour of magnetite nano-particles (MNPs) released in a water flow when subjected to an external magnetic field. MNPs physical and magnetic properties and their tendency to form aggregates were also investigated. A mathematical model was developed and applied using MNPs characterization and 3-D field maps generated by OPERA software, considering different magnet bar dimensions and particle aggregate sizes. Model was run to assess the MNPs trajectories, and the capture efficiency of a 10-cm height permanent magnet bar placed on the upper wall of a bench-scale rectangular duct in which MNPs are injected.Shorter MNPs trajectories were observed in the flow regions farther from the duct walls (lateral or bottom walls) where the frictional forces are lower. It is relevant to notice that the MNPs attraction is possible also in regions where the magnetic field is weak due to the high magnetic susceptibility of the system. MNP aggregate size significantly influences the particle dynamics with the trajectories of the larger particles converging more rapidly towards the magnet leading to their capture. However, this does not affect the global removal (∼90%) for aggregate diameters higher than 1.2 µm, demonstrating the general effectiveness of the investigated magnetic capture system, which is only partially influenced by the aggregate size variation. The comparison of modelled and experimental results shows the goodness of the developed model. Along with magnetic and aggregation studies and generated 3-D magnetic field maps, it represents a valid tool for future studies towards the development of practical applications for the magnetic removal of MNPs loaded by water contaminants.

Physical, structural and spectroscopic analysis of tellurite glass containing natural magnetite Fe3O4 nanoparticles

This paper reports the influence of the embedment of natural magnetite (Fe3O4) nanoparticles (NP) in tellurite glass containing Er3+ ions. Significance results on physical, structural and emission properties obtained from varying Fe3O4 nanoparticles in the glass network are well discussed. In this work, glass samples with composition (89-x) TeO2–10MgO – 1Er2O3 - (x)Fe3O4, (x = 0, 0.2, 0.4, 0.6 and 0.8 mol %) are prepared by melt quenching technique. X-ray diffraction shows that all samples exhibit amorphous nature. The TEM image shows the spherical shape of nanoparticles within an average diameter of ∼8 nm. Meanwhile, the HRTEM image of glass containing 0.4 mol % of Fe3O4 NPs shows the presence of Fe3O4 NPs with the interplanar distance of 2.2 Å and growth in the [ 113] direction. The density, molar volume and thermal parameters of Fe3O4 NPs dependence with thermal stability around 100 °C may be achieved. The IR spectra show the presence of structural group [TeO4] tbp and [TeO3] tp as confirmed by Raman spectroscopy. The indirect band gaps are ranged from (2.31–3.12) eV, reducing with the rising of Fe3O4 NPs. At lower concentrations of Fe3O4 NPs, the emission intensity of luminescence is enhanced while at higher Fe3O4 NPs the intensity is quenched due to the effect of spin-orbit coupling.

The vehicle braking systems as main source of inhalable airborne magnetite particles in trafficked areas

Magnetite (Fe3O4) nano-particles (MNPs) have been found in human tissues and causally linked to serious illnesses. The possible negative role of MNPs has been not still fully ascertained even though MNPs might cause health effects due to their magnetic property, redox activity and surface charge. The origin of MNPs in human tissues still remains to be unambiguously identified since biological processes, natural phenomena and anthropogenic production have been proposed. According to this latter increasingly convincing hypothesis, anthropogenic MNPs might enter mainly in the human body via inhalation, penetrate deeply into the lungs and in the alveoli and also migrate into the blood circulation and gather in the extrapulmonary organs and central nervous system. In order to identify the releasing source of the potentially inhalable MNPs, we pioneered an innovative approach to rapidly investigate elemental profile and morphology of a large number of airborne micron and sub-micron-sized Fe-bearing particles (FePs). The study was performed by collecting a large amount of micron and sub-micron sized inhalable airborne FePs in trafficked and densely frequented areas of Rome (Italy). Then, we have investigated individually the elemental profile and morphology of the collected particles by means of high-spatial resolution scanning electron microscopy, energy dispersive spectroscopy and an automated software purposely developed for the metal-bearing particles analysis. On the basis of specific elemental tracing features, the investigation reveals that almost the total amount of the airborne FePs is released by the vehicle braking systems mainly in the form of magnetite. Furthermore, we point out that our approach might be more generally used to identify the releasing sources of different inorganic airborne particles and to contribute to establish more accurately the impact of specific natural or anthropogenic particles on the environment and human health.

Chiral Magneto-Optical Properties of Supra-Assembled Fe3O4 Nanoparticles.

Research on the chiral magneto-optical properties of inorganic nanomaterials has enabled novel applications in advanced optical and electronic devices. However, the corresponding chiral magneto-optical responses have only been studied under strong magnetic fields of ≥1 T, which limits the wider application of these novel materials. In this paper, we report on the enhanced chiral magneto-optical activity of supra-assembled Fe3O4 magnetite nanoparticles in the visible range at weak magnetic fields of 1.5 mT. The spherical supra-assembled particles with a diameter of ∼90 nm prepared by solvothermal synthesis had single-crystal-like structures, which resulted from the oriented attachment of nanograins. They exhibited superparamagnetic behavior even with a relatively large supraparticle diameter that exceeded the size limit for superparamagnetism. This can be attributed to the small size of nanograins with a diameter of ∼12 nm that constitute the suprastructured particles. Magnetic circular dichroism (MCD) measurements at magnetic fields of 1.5 mT showed distinct chiral magneto-optical activity from charge transfer transitions of magnetite in the visible range. For the supraparticles with lower crystallinity, the MCD peaks in the 250-550 nm range assigned as the ligand-to-metal charge transfer (LMCT) and the inter-sublattice charge transfer (ISCT) show increased intensities in comparison to those with higher crystallinity samples. On the contrary, the higher crystallinity sample shows higher MCD intensities near 600-700 nm for the intervalence charge transfer (IVCT) transition. The differences in MCD responses can be attributed to the crystallinity determined by the reaction time, lattice distortion near grain boundaries of the constituent nanocrystals, and dipolar interactions in the supra-assembled structures.

Green synthesis of magnetic nanocomposite by Cordia Africana (CA) leave extract for the treatment of Methylene blue contaminated water

The magnetic behavior of individual magnetite (Fe3O4) nanoparticles (MNPs) has arisen considerable attention in environmental application. However, magnetic properties and stability weaken due to their high susceptibility to chemical activity (oxidation). Efforts have increasingly been made to encapsulate MNPs by green organic matrix, which considerably improve functionality, stability, cost and reduce back toxicity. Besides, the use of natural zeolite materials has been reported to endows considerable dispersibility and chemical stability for the composite MNPs. In this study, bio-based magnetite nanoparticles were synthesized using an aqueous extract of Cordia Africana (CA) leaves incorporated into the modified Natrolite (NAT) framework as an adsorbent for methylene blue (MB)dye removal from aqua solution. The prepared high dispersible Magnetite-NAT Nanocomposite (M/NAT-NC) was characterized by Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), and scanning electron microscope (SEM). The optimum adsorption efficiency of M/NAT-NCs was estimated by employing Response Surface Methodology (RSM)-based Box-Behnken Design (BBD) at different parameters. Accordingly, 0.5 g M/NAT-NCs, 40 mg/L, and pH 9 at 40 min were found to be the optimal conditions for best removal (98.6%). The adsorption data fitted best with the pseudo-second-order and Freundlich model, and the negative value of ∆G0 confirms the feasibility and spontaneity of the MB adsorption onto M/NAT-NCs. Besides, the regeneration of exhausted M/NAT-NCs reflected nearly similar removal efficiency as the new one; as such, M/NAT-NCs could be reasonably used for cationic dyes removal from aqueous media.

Polyethylene over magnetite-multiwalled carbon nanotubes for kerosene removal from water

In this study, a nano-adsorbent was prepared for kerosene removal from water. Multiwalled carbon nanotubes (MWCNTs) were functionalized with concentrated HNO3 (nitric acid). Subsequently, Fe3O4 (magnetite) nanoparticles were deposited on the MWCNTs to prepare a magnetite/MWCNTs (Fe-MWCNTs) nanocomposite. Then, polyethylene was added to the Fe-MWCNTs to fabricate a polyethylene/magnetite/MWCNTs (PE/Fe-MWCNTs) novel nanocomposite. The nano-adsorbent was characterized using BET, FTIR, Raman, XRD, TEM, and SEM. A kerosene–water model mixture was used for adsorption tests. Several parameters: adsorption time, adsorbent dose, solution pH, solution temperature, and kerosene concentration in the kerosene-water model mixture, were analyzed during adsorption experiments. After each batch experiment, kerosene concentration was determined using high-performance liquid chromatography (HPLC). Magnetic field was used to remove the adsorbent after each experiment. The kerosene adsorption capacity and removal efficiency of the PE/Fe-MWCNTs nanocomposite (3560 mg/g and 71.2 %, respectively) were higher than those of Fe-MWCNTs, ox-MWCNTs, and fresh MWCNTs (3154 mg/g and 63.1 %, 2204 mg/g and 44.0 %, and 2092 mg/g and 41.8 %, respectively). Kerosene adsorption followed a pseudo-second-order kinetic model (R2 = 0.999) and the Langmuir isotherm model, suggesting that adsorption was uniform and homogenous process.

Magnetite Fe3O4 Nanoparticles Enhance Mild Microwave Ablation of Tumor by Activating the IRE1-ASK1-JNK Pathway and Inducing Endoplasmic Reticulum Stress.

PurposeWith the development of nanomedicine, microwave ablation enhanced by multifunctional nanoplatforms has been widely studied for synergistic cancer therapy. Though scientists have got a lot of significant achievements in this field, the detailed molecular mechanisms and potential targets of microwave ablation enhanced by multifunctional nanoplatforms still need further exploration. In this study, we found that a kind of magnetite Fe3O4 nanoparticles (Fe3O4 NPs) could induce severe endoplasmic reticulum stress and activate cancer apoptosis under the irradiation of mild microwave.MethodsIn this study, plenty of studies including cell immunofluorescence, mitochondrial membrane potential, electron microscopy, atomic force microscopy and microwave ablation in vivo were conducted to explore the molecular mechanisms and potential targets of microwave ablation enhanced by the Fe3O4 NPs.ResultsThe IRE1-ASK1-JNK pathway was strongly activated in A375 cells treated with both Fe3O4 NPs and mild microwave. The endoplasmic reticulum of the A375 cells was significantly dilated and exhibited ballooning degeneration. By investigating the mitochondrial membrane potential (ΔΨm), we found that the mitochondria of cancer cells had been significantly damaged under microwave treatment coupled with Fe3O4 NPs. In addition, melanoma of B16F10-bearing mice had also been effectively inhibited after being treated with Fe3O4 NPs and microwave.ConclusionIn this study, we found that a kind of magnetite Fe3O4 nanoparticles could induce severe ER stress and activate cancer apoptosis under mild microwave irradiation. Apparent apoptosis had been observed in the A375 cells under a scanning electron microscope and transmission electron microscope. Moreover, melanoma had also been inhibited effectively in vivo. As a result, the endoplasmic reticulum stress is a promising target with clinical potential in nanomedicine and cancer therapy.

Modification of phytochemical production and antioxidant activity of Dracocephalum kotschyi cells by exposure to static magnetic field and magnetite nanoparticles

Dracocephlum kotschyi Boiss is a genus in Lamiaceae family and a medicinal herb native to Iran. The cell suspension cultures were treated by static magnetic field (SMF) and Fe3O4 magnetite nanoparticles (MNP) to understand the production yield of secondary metabolites. The treatment procedure was done by cultivating the cells either with 100 ppm MNP, SMFs, or simultaneous exposure to both MNP and SMFs. The SMF at 30 mT was uniformly applied to the cells either for 3 or 4 days with a 3 h per day or a 5 h per day intervals, respectively. The contents of phenolics and phytochemicals were then examined by high performance liquid chromatography and UV–Vis spectrophotometer. These treatments imposed oxidative stress and induced polyphenol oxidase and phenylalanine ammonia lyase, accompanied by enhanced production of phenolics, anthocyanins, flavonoids, and lignin. The highest membrane embrittlement and elicitation was found upon simultaneous application of the MNPs and SMFs, followed by the MNP and SMFs. The contents of naringin, rosmarinic acid, quercetin, thymol, carvacrol, apigenin, and rutin increased in the intracellular biomass of all treated cells and extracellular culture media. These findings propose the potential of these elicitors in simultaneous production and secretion of these phytochemicals into culture media.

Green biosynthesis and physicochemical characterization of Fe3O4 nanoparticles using Punica granatum L. fruit peel extract for optoelectronic applications

Green biosynthesis of Fe3O4 nanoparticles (NPs) using plant extract is desired, as the plant extract is safe for humans and the environment. In this study, magnetite Fe3O4 NPs were greenly prepared using Punica granatum L. fruit peel extract as a reducing and capping agent. The effect of iron precursor contraction (0.01–0.1 M, FeCl3) was studied. The Fe3O4 crystalline with an average crystallite size range from 21 to 23 nm was proven by X-ray powder diffraction. Scanning electron microscopy images showed that the synthesized Fe3O4 NPs were mostly cubical. Ultraviolet-visible spectra showed that the prepared Fe3O4 NPs exhibit absorption at 270 nm related to the Fe3O4 NPs with a direct bandgap ranging from 1.87 to 2.26 eV and indirect bandgap of 2.16–2.48 eV. Fourier transform infrared spectroscopy analysis showed two characteristic absorption bands at 515 and 567 cm−1, which proved the successful formation of Fe3O4. The proposed method using Punica granatum L. fruit peel extract offers an economical and environmentally friendly route for synthesizing many other types of metal oxides.

On-Demand Release of Drug from Magnetic Nanoparticle-Loaded Alginate Beads.

Targeted delivery and controlled release of drugs has been considered to be an important therapeutic approach since it could allow a better treatment efficiency and less side effects. In this research, magnetite Fe3O4 nanoparticles were successfully synthesized via the coprecipitation method and then loaded in alginate beads with berberine as a drug model for drug release application. Various factors such as pH values of the suspended environment and surface modifications of the drug carrier could be exploited to adjust the amount of drug release. More importantly, the amount of drug release could be effectively controlled by an on-off switching operation of a static magnetic field.

Synthesis and characterization of magnetite Fe3O4 nanoparticles using one step laser ablation in water under effect of external magnetic field

Iron oxide nanoparticles were prepared by Nd:YAG laser ablation in water under effect of an external magnetic field. The X-ray diffraction analysis of iron oxides nanoparticles showed that the synthesized nanoparticles were crystalline magnetite Fe3O4. The intensity of the x-ray peaks increased after applying the magnetic field. Field emission scanning electron microscope (FE-SEM) showed that the average grain size of the nanoparticles was decreased from 85nm to 45nm and the particles agglomeration has been decreased after applying the magnetic field. The energy gap increased after applying the magnetic field during the ablation process. Raman spectroscopy of the iron oxide nanoparticles showed formation of T1g and A1g modes.