Prepared Fe3O4 Nanoparticles Research Articles

High‐performance symmetric supercapacitor using cost‐efficient iron oxide (Fe3O4) nanoparticles

AbstractWe investigated Fe3O4 nanoparticles (NPs) for a symmetric supercapacitor (SSC) under ambient conditions from synthesizing material to device fabrication. The prepared Fe3O4 NPs are characterized using different characterization, X‐ray diffraction, Raman and FTIR spectroscopy. The electrochemical performance of supercapacitor (SC) is measured in two electrode systems using coin‐cell assembly at various scan rates varying from 10–100 mV s−1, and cyclic voltammetry measurements are investigated from −0.8 to 0.6 V window. The Fe3O4 NPs based SSC shows an energy density of 24.99 Wh kg−1 with the high specific capacitance of 91.82 F g−1 at 10 mV s−1 scan rate. At a current rate of 4 A g−1, the power density reaches 2000 W kg−1. The Fe3O4 NPs based SSC exhibits a quick charge and discharge mechanism at various current rates and is stable over 500 galvanostatic chargingdischarging cycles at a current rate of 4 A g−1. The fabricated SSC showed >60% capacitance retention even after operating for 1000 cyclic voltammetry cycles at a scan rate of 100 mV s−1. A reasonable choice for SSC electrodes with high power density, and the outstanding resilience of electrodes is further shown by cyclic stability and impedance study exhibiting a negligible change in the different impedance elements. The potential of the fabricated SSC is demonstrated by lightening a light emitting diode (LED) light as a practical aspect for future applications.

Optical and photo-thermal conversion characteristics of recyclable nano-ferrofluid under the external magnetic field

The efficient conversion of solar energy through photo-thermal processes holds significant importance in realizing cleaner and sustainable energy provision. To optimize the solar photo-thermal conversion performance, Water-Ethylene glycol-based Fe3O4 nano-ferrofluid was applied under the action of an external Magnetic Field (MF) in this work. The saturation magnetic intensity of prepared Fe3O4 nanoparticles with the diameter of 12.61 nm is 51.38 emu/g. The optical properties of the prepared nano-ferrofluid were investigated in the concentration range of 0.025–0.1 wt%. The results indicated the optical transmittance of nano-ferrofluid decreased with accumulation of concentration, and the absorption peaks were around 220 nm, 500–600 nm, as well as 970 nm. It is shown that both vertical and horizontal MF would improve the photo-thermal conversion efficiency of Fe3O4 nano-ferrofluid within intensity range from 5 mT to 60 mT because the chain-like structure formed by the nanoparticles enhanced the thermal conductivity, and the vertical MF was more beneficial with the improvements of 44.91%–70.28%. Moreover, the photo-thermal conversion efficiency of nano-ferrofluid gradually rises with the increase of vertical MF intensities. However, there is the optimal MF intensity for the horizontal MF. As a result, the nano-ferrofluid with 0.1 wt% concentration has the maximum enhancement of 70.28% at the vertical MF of 60 mT. In addition, the recovery properties of nanoparticles were also studied under the action of MF, and the recovery efficiency of 82.4% was obtained after the action of MF with 200 mT for 100 min.

Facile Prepared Fe3O4 Nanoparticles as a Nano-Catalyst on photo-Fenton process to remediation of methylene blue dye from water: Characterisation and Optimization

<p>In this research, a simple method for the preparation of Fe3O4 nanoparticles (Fe3O4NPs) with an average size of 38.05 nm via co-precipitation was investigated. X-ray diffraction (DRX), scanning electron microscopy (SEM), and infrared spectroscopy (FT-IR) were used to characterize obtained Fe3O4 nanoparticles. These Fe3O4NPs were then used as nano-catalysts to degrade Methylene Blue (MB) in an aqueous solution via the Photo Fenton-like process. Also, under room solar light and low temperature, the photocatalytic activity of Fe3O4NPs for degrading MB was optimized through various experimental factors such as pH (ranging from 2 to 8), H2O2 concentration (from 10-2 to 5 × 10-1), catalyst amount (20 to 60 mg), and target organic compound concentrations (10 to 40 mg/L). The optimal experimental conditions were found to be a pH of 3, a dye concentration of 40 mg/L, and 40 mg of Fe3O4NPs as nano-catalyst. These conditions led to a high degree of removal (>86%) of MB dye from water. The pseudo-second-order kinetic model was the suitable model to describe the degradation of MB dye with a coefficient value of 0.969. From this, it was concluded that Fe3O4NPs could act as an effective nano-catalyst for a sustainable and environmentally friendly way to eliminate organic pollutants in water and wastewater. Keywords: Fe3O4Nps, structural characterization, BM degradation, photo-Fenton Oxidation process, pseudo-first-order Model, Nanocatalyst.</p>

Magnetically recyclable ZnO coated Fe3O4 nanocomposite for MO dye degradation under UV-light irradiation

We describe the synthesis of zinc oxide (ZnO) coated magnetite (Fe3O4) [ZnO/Fe3O4] nanocomposite and its photocatalytic application towards the methyl orange (MO) dye degradation. ZnO/Fe3O4 nanocomposite was prepared by opting the ex-situ mechanical stirring process of ZnO powder and solvothermally prepared Fe3O4 nanoparticles. The photocatalytic properties of the ZnO/Fe3O4 nanocomposite were investigated, and the degradation of methyl orange (MO) dye was found to be 84% in 120 min under UV light. The electron transfer mechanism might explain the still debatable MO dye degradation mechanism in the present case. The photogenerated electrons transfer to the conduction band (CB) of Fe3O4 from the CB of ZnO under UV light exposure. This results in the creation of defect levels (i.e., Fe2+ or Fe3+) in ZnO, lowering the CB of ZnO. The reusability and efficient magnetic separability of ZnO/Fe3O4 photocatalyst was established by 60% degradation after four cycles under UV light irradiation. The nanocomposite's XRD pattern before and after photocatalytic degradation exhibited no structural change, demonstrating the photocatalyst's outstanding stability. Our investigations demonstrated the potential for MO dye degradation by ZnO/Fe3O4 nanocomposite under UV light irradiation.

Preparation of Selenium-Based Drug-Modified Polymeric Ligand-Functionalised Fe3O4 Nanoparticles as Multimodal Drug Carrier and Magnetic Hyperthermia Inductor.

In recent years, much effort has been invested into developing multifunctional drug delivery systems to overcome the drawbacks of conventional carriers. Magnetic nanoparticles are not generally used as carriers but can be functionalised with several different biomolecules and their size can be tailored to present a hyperthermia response, allowing for the design of multifunctional systems which can be active in therapies. In this work, we have designed a drug carrier nanosystem based on Fe3O4 nanoparticles with large heating power and 4-amino-2-pentylselenoquinazoline as an attached drug that exhibits oxidative properties and high selectivity against a variety of cancer malignant cells. For this propose, two samples composed of homogeneous Fe3O4 nanoparticles (NPs) with different sizes, shapes, and magnetic properties have been synthesised and characterised. The surface modification of the prepared Fe3O4 nanoparticles has been developed using copolymers composed of poly(ethylene-alt-maleic anhydride), dodecylamine, polyethylene glycol and the drug 4-amino-2-pentylselenoquinazoline. The obtained nanosystems were properly characterised. Their in vitro efficacy in colon cancer cells and as magnetic hyperthermia inductors was analysed, thereby leaving the door open for their potential application as multimodal agents.

Concurrent Dual-Contrast Enhancement Using Fe3O4 Nanoparticles to Achieve a CEST Signal Controllability.

Traditional T2 magnetic resonance imaging (MRI) contrast agents have defects inherent to negative contrast agents, while chemical exchange saturation transfer (CEST) contrast agents can quantify substances at trace concentrations. After reaching a certain concentration, iron-based contrast agents can "shut down" CEST signals. The application range of T2 contrast agents can be widened through a combination of CEST and T2 contrast agents, which has promising application prospects. The purpose of this study is to develop a T2 MRI negative contrast agent with a controllable size and to explore the feasibility of dual contrast enhancement by combining T2 with CEST contrast agents. The study was carried out in vitro with HCT-116 human colon cancer cells. A GE SIGNA Pioneer 3.0 T medical MRI scanner was used to acquire CEST images with different saturation radio-frequency powers (1.25/2.5/3.75/5 μT) by 2D spin echo-echo planar imaging (SE-EPI). Magnetic resonance image compilation (MAGiC) was acquired by a multidynamic multiecho 2D fast spin-echo sequence. The feasibility of this dual-contrast enhancement method was assessed by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, dynamic light scattering, ζ potential analysis, inductively coupled plasma, X-ray photoelectron spectroscopy, X-ray powder diffraction, vibrating-sample magnetometry, MRI, and a Cell Counting Kit-8 assay. The association between the transverse relaxation rate r2 and the pH of the iron-based contrast agents was analyzed by linear fitting, and the linear relationship between the CEST effect in different B1 fields and pH was analyzed by the ratio method. Fe3O4 nanoparticles (NPs) with a mean particle size of 82.6 ± 22.4 nm were prepared by a classical process, and their surface was successfully modified with -OH active functional groups. They exhibited self-aggregation in an acidic environment. The CEST effect was enhanced as the B1 field increased, and an in vitro pH map was successfully plotted using the ratio method. Fe3O4 NPs could stably serve as reference agents at different pH values. At a concentration of 30 μg/mL, Fe3O4 NPs "shut down" the CEST signals, but when the concentration of Fe3O4 NPs was less than 10 μg/mL, the two contrast agents coexisted. The prepared Fe3O4 NPs had almost no toxicity, and when their concentration rose to 200 μg/mL at pH 6.5 or 7.4, they did not reach the half-maximum inhibitory concentration (IC50). Fe3O4 magnetic NPs with a controllable size and no toxicity were successfully synthesized. By combining Fe3O4 NPs with a CEST contrast agent, the two contrast agents could be imaged simultaneously; at higher concentrations, the iron-based contrast agent "shut down" the CEST signal. An in vitro pH map was successfully plotted by the ratio method. CEST signal inhibition can be used to realize the pH mapping of solid tumors and the identification of tumor active components, thus providing a new imaging method for tumor efficacy evaluation.

Preparation and characterization of Fe3O4 nanoparticles via a hydrothermal process with propanediol as the solvent

Fe3O4 nanomaterials have received great attention in various technology fields. However, the limitations are Fe3O4 is easy to agglomerate and obtaining Fe3O4 nanoparticles of tunable magnetism and controllable size, and well-dispersed ability remains a challenge. In this study, a simple hydrothermal process with propanediol as the solvent was used to prepare Fe3O4 nanoparticles. In the optimization of preparation conditions, three key factors (hydrothermal temperature, hydrothermal time, and solvent volume) were optimized by x-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The results showed that the magnetism and the phase content of the prepared Fe3O4 were controllable during the optimization process. The optimum hydrothermal temperature was 170 °C, hydrothermal time was 18 h and solvent volume was 40 ml. The elemental composition, surface morphology, and magnetic properties of Fe3O4 nanoparticles were characterized. The prepared Fe3O4 nanoparticles exhibited superparamagnetic properties and high crystallinity, with an average particle size of 20 nm, a specific surface area of 84.756 m2 g−1, a pore volume of 0.265 cm3 g−1, and saturation magnetization (Ms) of 129.38 emu g−1.

Preparation of PEI-modified nanoparticles by dopamine self-polymerization for efficient DNA delivery.

Achieving efficient and safe gene delivery is of greatsignificance to promote the development of gene therapy. In this work, a polydopamine (PDA) layer was coated on the surface of Fe3 O4 nanoparticles (NPs) by dopamine (DA) self-polymerization, and then magnetic Fe3 O4 NPs were prepared by the Michael addition between amino groups in polyethyleneimine (PEI) and PDA. The prepared Fe3 O4 NPs (named Fe3 O4 @PDA@PEI) were characterized by Fourier transform infrared (FTIR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). As an efficient and safe gene carrier, the potential of Fe3 O4 @PDA@PEI was evaluated by agarose gel electrophoresis, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, fluorescence microscopy, and flow cytometry. The results show that the Fe3 O4 @PDA@PEI NPs are stable hydrophilic NPs with a particle size of 50-150nm. It can efficiently condense DNA at low N/P ratios and protect it from nuclease degradation. In addition, the Fe3 O4 @PDA@PEI NPs have higher safety than PEI. Further, the Fe3 O4 @PDA@PEI/DNA polyplexes could be effectively absorbed by cells and successfully transfected and exhibit higher cellular uptake and gene transfection efficiency than PEI/DNA polyplexes. The findings indicate that the Fe3 O4 @PDA@PEI NPs have the potential to be developed into a novel gene vector.

Fabrication of biogenic iron oxide and their efficiency to detect carbofuran in vegetable samples

First time we approached green way method to synthesize iron oxide (Fe3O4) nanoparticles using aqueous extract of Artocarpus heterophyllus seeds through an environmentally friendly method. Further, as prepared Fe3O4 nanoparticles were characterized and confirmed by different analytical techniques such as Fourier transform infrared (FT-IR) spectroscopy, Raman spectrum, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectrometer (EDAX) employed to determine the functional groups, crystalline structure, size, and shape of nanoparticles. A spherical with a size of 34 nm, and highly stable iron oxide nanoparticles were obtained. Further, Fe3O4 nanoparticles have been coated on the magnetic glassy carbon electrode (Fe3O4/MGCE) and applied for the electrocatalytic oxidation of carbofuran (CF) was examined by using cyclic voltammetry (CV) and differential pulse voltammetric (DPV) techniques. The Fe3O4/MGCE has shown excellent catalytic activity towards CF oxidation in the concentration of 0.3 – 38.5 µM with LOD of 0.01 µM and sensitivity of 6.53 ± 0.08 µA µM−1 cm−2. Moreover, the practical applicability of the fabricated Fe3O4/MGCE has been applied for the detection of CF in different vegetable samples and the obtained results were compared with HPLC outputs.

Fe3O4-PEI Nanocomposites for Magnetic Harvesting of Chlorella vulgaris, Chlorella ellipsoidea, Microcystis aeruginosa, and Auxenochlorella protothecoides.

Magnetic separation of microalgae using magnetite is a promising harvesting method as it is fast, reliable, low cost, energy-efficient, and environmentally friendly. In the present work, magnetic harvesting of three green algae (Chlorella vulgaris, Chlorella ellipsoidea, and Auxenochlorella protothecoides) and one cyanobacteria (Microcystis aeruginosa) has been studied. The biomass was flushed with clean air using a 0.22 μm filter and fed CO2 for accelerated growth and faster reach of the exponential growth phase. The microalgae were harvested with magnetite nanoparticles. The nanoparticles were prepared by controlled co-precipitation of Fe2+ and Fe3+ cations in ammonia at room temperature. Subsequently, the prepared Fe3O4 nanoparticles were coated with polyethyleneimine (PEI). The prepared materials were characterized by high-resolution transmission electron microscopy, X-ray diffraction, magnetometry, and zeta potential measurements. The prepared nanomaterials were used for magnetic harvesting of microalgae. The highest harvesting efficiencies were found for PEI-coated Fe3O4. The efficiency was pH-dependent. Higher harvesting efficiencies, up to 99%, were obtained in acidic solutions. The results show that magnetic harvesting can be significantly enhanced by PEI coating, as it increases the positive electrical charge of the nanoparticles. Most importantly, the flocculants can be prepared at room temperature, thereby reducing the production costs.

Synthesis of heterogeneous photo-Fenton catalyst from iron rust and its application to degradation of Acid Red 97 in aqueous medium

In this work, magnetic nanoparticles were synthesized from iron rust waste and used as a catalyst for photo-Fenton degradation of Acid red 97 (AR97). The morphology and size of Fe3O4 nanoparticles could be controlled by adding an appropriate amount of water as co-solvent in solvothermal treatment. For a comparative study, α-FeOOH and α-Fe2O3 with nanorod shape were also prepared from iron rust and employed as photo-Fenton catalyst. The photo-Fenton degradation results showed that the prepared Fe3O4 nanoparticles with spherical-like shape possessed higher catalytic activity than octahedral-shaped Fe3O4, α-FeOOH, and α-Fe2O3. It was demonstrated that the synergetic effect between H2O2 and oxalic acid (OA) led to an improvement in the catalytic efficiency of the photo-Fenton system towards AR97 degradation in awide pH range. At 180 min, about 81% of total organic carbon (TOC) was removed. Thus, the mineralization of organic matter is strongly involved during the photo-Fenton process. The quenching experiments showed that •OH radical played a crucial role in the degradation of AR97 by Fe3O4/H2O2/OA/UV system. Benefiting from the high catalytic activity and easy magnetic separation, the prepared Fe3O4 nanoparticles revealed good stability and reusability even after five consecutive cycles. This work offers a sustainable and effective way to recycle iron rust waste into an efficient catalyst for the degradation of organic contaminants in water.

Visualizing the Potential Impairment of Polymyxin B to Central Nervous System Through MR Susceptibility-Weighted Imaging.

Polymyxin B (PMB) exert bactericidal effects on the cell wall of Gram-negative bacteria, leading to changes in the permeability of the cytoplasmic membrane and resulting in cell death, which is sensitive to the multi-resistant Gram-negative bacteria. However, the severe toxicity and adverse side effects largely hamper the clinical application of PMB. Although the molecular pathology of PMB neurotoxicity has been adequately studied at the cellular and molecular level. However, the impact of PMB on the physiological states of central nervous system in vivo may be quite different from that in vitro, which need to be further studied. Therefore, in the current study, the biocompatible ultra-uniform Fe3O4 nanoparticles were employed for noninvasively in vivo visualizing the potential impairment of PMB to the central nervous system. Systematic studies clearly reveal that the prepared Fe3O4 nanoparticles can serve as an appropriate magnetic resonance contrast agent with high transverse relaxivity and outstanding biosafety, which thus enables the following in vivo susceptibility-weighted imaging (SWI) studies on the PMB-treated mice models. As a result, it is first found that the blood-brain barrier (BBB) of mice may be impaired by successive PMB administration, displaying by the discrete punctate SWI signals distributed asymmetrically across brain regions in brain parenchyma. This result may pave a noninvasive approach for in-depth studies of PMB medication strategy, monitoring the BBB changes during PMB treatment, and even assessing the risk after PMB successive medication in multidrug-resistant Gram-negative bacterial infected patients from the perspective of medical imaging.

Synthesis and characterisation of iron oxide (Fe3O4) ferrofluid nanoparticles coated by poly (vinyl butyral) with microsphere

Objective: Synthesis of magnetic nano Iron oxide (Fe3O4) ferrofluid nanoparticles using chemical methods and its characterization studies Method: Iron oxide (Fe3O4) ferrofluid nanoparticles is synthesized by using the chemical co-precipitation technique, ferric and ferrous salts in the alkaline medium, which is known as Reimer’s procedure. Results: Nano iron oxide (Fe3O4) particles have different magnetic properties and different magnetic moments, differentiating macroscopic iron oxide in suspended particles. The ratio of surface to volume increases along with the decrease in atomic size so that the surface properties are essential for using any nano-material. Prepared Fe3O4 nanoparticles were coated with oleic acid (C18H34O2) and polyvinyl butyral((C8H14O2)n), further characterized by Materials characterization techniques (SEM, XRD and FTIR). Magneto-rheological (MR) fluid has been one of the interesting studies the shear stress of PVB coated nano iron with microsphere has approximately the same as of PVB coated nano iron but shows very high shear stress withstanding capacity at 650 s-1 shear rates. Conclusion: The permanence of the magnetic colloidal depends on the thermal contribution and the balance between attractive and repulsive interactions.

Synthesis and surface modification of magnetic Fe3O4@SiO2 core-shell nanoparticles and its application in uptake of scandium (III) ions from aqueous media.

The main objective of this work is to produce an eco-friendly and economically nano-adsorbent which can separate scandium metal ions Sc from a model aqueous phase prior to applying these adsorbents in industrial filed. The magnetic core-shell structure Fe3O4@SiO2 nanoparticles were synthesized by modified Stöber method and functionalized with (3-aminopropyl) triethoxysilane APTES as a coupling agent and ethylenediaminetetraacetic acid (EDTA) as a ligand. Magnetic nano support adsorbents exhibit many attractive opportunities due to their easy removal and possibility of reusing. The ligand grafting was chemically robust and does not appreciably influence the morphology or the structure of the substrate. To evaluate the potential, the prepared hybrid nanoparticles were used as nano-adsorbent for Sc ions from model aqueous solutions due to the fact that rare earth elements (REEs) have a strong affinity for oxygen and nitrogen donors. The iron oxide nanoparticles were prepared by co-precipitation method at pH 10 and pH 11 to get the best morphology and nanoscale dimensions of iron oxide magnetic nanoparticles. The particle size, morphology, specific surface area, and surface modification were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), and X-ray powder diffraction (XRD). The results showed that the Fe3O4 nanoparticles with average particle size of 15 ± 3 nm were successfully synthesized at pH 11, and 25 °C. Moreover, the prepared Fe3O4 nanoparticles were coated with amorphous SiO2 and functionalized with amino and carboxyl groups. The adsorption study conditions of Sc are as follows: the initial concentrations of the Sc model solution varied 10-50 mg/L, 20 mL volume, 20-80 mg of the Fe3O4@SiO2-COO adsorbent, pHrange of 1-5, and 5 h contact time at 25 °C temperature. The adsorption equilibrium was represented with Langmuir, Freundlich, and Temkin isotherm models. Langmuir model was found to have the correlation coefficient value in good agreement with experimental results. However, the adsorption process followed pseudo-second-order kinetics.

The Investigation of Mixed Ferrofluids Containing Iron Oxide nanoparticles and Microspheres

The aim of the present work is the synthesis and characterization of iron oxide (Fe3O4) nanoparticles. These nanoparticles are coated with oleic acid and polyvinyl butyral and mixed with microspheres and further developed ferrofluids with silicon oil. Studies of the performance of the nanoparticles in these ferrofluids with and without coating agents were carried out. The nanoparticles were synthesized using the chemical co‐precipitation technique and coated with oleic acid and polyvinyl butyral, and it further mixed with microsphere ferrofluids and developed using silicon oil. The prepared Fe3O4 nanoparticles and their coated forms of oleic acid and polyvinyl butyral were mixed with microspheres; furthermore, ferrofluids were developed with silicon oil. All forms of these ferrofluids are characterized for morphology and phase purity (SEM, XRD, and FTIR). The iron oxide (Fe3O4) nanoparticles have shown different magnetic properties, differentiating macroscopic iron oxide in suspended particles. The ratio of surface to volume increases along with the decrease in atomic size, essential for assessing the surface morphological properties. The magneto‐rheological (MR) fluids were determined, and shear stress of Expancel microsphere mixed iron oxide nanoparticle with and without them was found almost equal. However, the ferrofluid with PVB coated nanoparticles and microspheres emerged as a stable rheological ferrofluid, sustaining high shear stress and low viscosity with increasing shear rate. Also, shear rates up to 650 s−1 have been observed, showing very high shear stress withstanding capacity. The stability and performance of the magnetic colloidal ferrofluids depend on the thermal contribution and the balance between attractive/repulsive interactions.

The activation energy and antibacterial investigation of spherical Fe3O4 nanoparticles prepared by Crocus sativus (Saffron) flowers

We proposed a simple and environmental-friendly method to prepare magnetite nanoparticles and their application as antibacterial material. We successfully prepared Fe3O4 nanoparticles using Crocus Sativus (Saffron) flowers followed by calcination at 400 ˚C for 15 minutes. The UV–Visible spectroscopy was used to study the bandgap energy of the prepared Fe3O4 nanoparticles and the value was found to be 3.23 eV. The scanning electron microscopy (SEM) was used to study the structure and morphology and X-ray diffraction was used to study the phase and crystallite size of the magnetite nanoparticles. The percentage weight loss, the enthalpy change and activation energy of Fe3O4 nanoparticles were calculated by using the thermogravimetric (TG) and differential thermal analysis (DTA) respectively. The DTA curve at a heating rate of 6, 8 and 10˚C/min shows endothermic peaks at 586, 594 and 600˚C respectively. The activation energy of Fe3O4 nanoparticles was calculated by the Kissinger method and was found to be 8.09 kJ/moles. The antibacterial activity of Fe3O4 nanoparticles was carried out against 3 gram-positive and 3 gram-negative bacteria by using a minimum inhibition concentration (MIC) assay method and they showed excellent antibacterial activity against gram-negative bacterial strains only.

Alternating Magnetic Field and Ultrasound Waves as Size Controlling Parameters in Preparation of Superparamagnetic Fe3O4 Nanoparticles

Magnetic nanoparticles have been studied extensively owing to their widespread applications. Here, a novel and simple co-precipitation method is introduced in the presence of an external alternating magnetic field along with ultrasound waves for the synthesis of uniform magnetite (Fe₃O₄) nanoparticles with an average particle size of below 10 nm, the results of which were compared further. These agitating probes were employed to induce nucleation process of Fe₃O₄ nanoparticles resulting in creation of such particles with remarkable magnetic properties. These were assessed by XRD, TEM, vibrating sample magnetometer (VSM), AFM, and magnetic force microscopy (MFM) analyses. XRD patterns revealed the spinel phase of the obtained magnetite. The size and morphology of the nanoparticles were determined by AFM, TEM, and HR-TEM. The results indicated efficient control over size distribution in such new processes. The magnetic properties of the prepared Fe₃O₄ nanoparticles were characterized by MFM and VSM, demonstrating their superparamagnetic behavior. They showed saturation magnetization ranging from 57.4 to 79.4 emu/g with coercivity of 11.9 to 12.55 Oe, depending on the applied procedure.

Immobilization studies of Candida Antarctica lipase B on gallic acid resin-grafted magnetic iron oxide nanoparticles.

Purpose: Here, we present the successful preparation of a highly efficient gallic acid resin grafted with magnetic nanoparticles (MNPs) and containing a branched brush polymeric shell.Methods: Using a convenient co-precipitation method, we prepared Fe3O4 nanoparticles stabilized by citric acid. These nanoparticles underwent further silica modification and amino functionalization followed by gallic acid functionalization on their surface. Under alkaline conditions, we used a condensation reaction that combined formaldehyde and gallic, to graft the gallic acid−formaldehyde resin on the surface. We then evaluated the polymer-grafted MNPs to assay the Candida Antarctica B lipase(Cal-B) immobilization via physical adsorption.Conclusion: Furthermore, during optimization of parameters that defined conditions of immobilization, we found that the optimum immobilization was achieved in 15 mins. Also, optimal immobilization temperature and pH were 38ºC and 7.5, respectively. In addition, the reusability study of immobilized lipase polymer-grafted MNPs was done by isolating the MNPs from the reaction medium using magnetic separation, which showed that grafted MNPs reached 5 cycles with 91% activity retention.

Application of luteinizing hormone-releasing hormone-ferrosoferric oxide nanoparticles in targeted imaging of breast tumors.

BackgroundFerrosoferric oxide (Fe3O4) nanoparticles are a commonly used magnetic resonance imaging (MRI) reagent. Luteinizing hormone-releasing hormone (LHRH) is highly expressed on the surfaces of tumors, but its expression is low or absent in the corresponding normal tissues, allowing it to be used for targeted imaging and treatment.MethodsWe prepared Fe3O4 nanoparticles using a chemical co-precipitation method, performed coupling with chitosan to prepare LHRH-Fe3O4 nanoparticles, and explored the application value of LHRH-Fe3O4 nanoparticles in targeted imaging and treatment of breast tumors through in vitro and in vivo experiments.ResultsThe particle size of the LHRH-Fe3O4 nanoparticles was 10 nm, and they could be taken in by human MCF-7 breast cancer cells. The nanomaterial had low cytotoxicity. In vivo MRI experiments showed that LHRH-Fe3O4 could effectively concentrate on the tumor under the action of a magnetic field. It also had a good negative enhancement effect that significantly reduced the signal intensity of the T2 field, allowing it to be used as a contrast agent of the T2 field.ConclusionLHRH-Fe3O4 nanoparticles serve the purpose of targeting contrast agents to target sites and are expected to be used for targeted imaging and treatment of cancers with high LHRH expression.

Synthesis and Photocatalytic Studies of Fe3O4 Nanoparticles

Advances in nanoscience and nanotechnology are centered in the control of size and shape of nanoparticles, as well as attainment of the extended arrangement of nanoparticles in different structures. One dimensional nanostructured magnetic materials are interesting because of their enhanced magnetic properties and potential applications such as information storage and gas sensor. The advanced electronic applications of Fe3O4 magnetic nanomaterials are considered to require improvement in the powder processing, particularly, meticulous particle control in the nanometer range and phase purity. Structural properties of Fe3O4 nanoparticles were synthesized via sol-gel protocol, the morphology and particles size were determined by X-ray diffraction, scanning electron microscope, transmission electron microscope, energy dispersive X-ray, UV- diffuse reflectance spectrophotometer and particle size analyzer. The structure of as prepared Fe3O4 nanoparticles was used for photocatalytic applications.