Modified Fe3O4 Nanoparticles Research Articles

Immobilized Co(acac)2 on modified Fe3O4 nanoparticles as a magnetically separable epoxidation catalyst

Fe3O4 nanoparticles were prepared and modified with (3-aminopropyl) trimethoxysilane (APTMS) followed by complexation with Co(acac)2. The prepared nanocatalyst, designated as Fe3O4@APTMS@Co(acac)2 was characterized by FTIR, XRD, SEM, and TEM techniques. It was found that Fe3O4@APTMS@Co(acac)2 successfully catalyzes the epoxidation of cyclooctene, styrene, cyxlohexene, trans-stilbene, and norbornene with O2 as an oxidant and isobutyraldehyde (RCHO) as a co-reductant with 48–100 % reactivity and 40–92 % selectivity.

Preparation of a novel ferrofluidic photoresist for two-photon photopolymerization technique

We present a novel route for the preparation of ferrofluidic photoresist compatible with two-photon photopolymerization (TPP). To get a homogeneous ferrofluidic photoresit, the compatibility of photoresist and magnetic materials has been improved. Monodispersed Fe3O4 nanoparticles synthesized via thermal decomposition of iron precursor were stabilized by 6-(methacryloyloxy) hexanoic acid (a kind of acrylate-based monomer). A ferrofluidic photoresist was prepared by doping the modified Fe3O4 nanoparticles in acrylate-based resin. In this way, the dispersibility of nanoparticles in photoresist was enhanced significantly. As a representative example, a precise magnetic micron-sized spring was created. In the test of the magnetic response, the sensitivity of magnetic microspring was improved remarkably due to the optimization of the ferrofluidic photoresist. When the intensity of external magnetic field reached a value of 1500Gs, the deformation rate of the microspring would get to 2.25, indicating the compatibility of the ferrofluidic photoresist in microfabrication.

Preparation and Characterization of Fe3O4/Ethiodized‐oil Magnetic Fluids Used in Arterial Embolization Hyperthermia

AbstractFe3O4 nanoparticles (NPs) were prepared by the co‐precipitation of Fe3+ and Fe2+ with ammonium hydroxide, and were modified by four different surfactants. The modified Fe3O4 NPs were characterized by Fourier transform infrared spectroscopy, X‐ray powder diffraction, transmission electron microscopy and vibrating sample magnetometer. Then, the modified Fe3O4 NPs were dispersed in ethiodized‐oil by mechanical agitation and ultrasonic vibration to obtain stable Fe3O4/ethiodized‐oil magnetic fluids (MFs). The magnetic properties and rheological properties of the MFs were measured using a Gouy magnetic balance and a rotational rheometer, respectively. The saturation magnetization of the Fe3O4 modified by oleic acid was 52.1 emu/g. Furthermore, the result showed that the inductive heating effect of oleic acid stabilized Fe3O4/ethiodized‐oil MF was remarkable and it only took 650 s for the temperature rising from 25°C to 65°C. The specific absorption rate of the MF was 50.16 W/(g of Fe). It had a potential application in arterial embolization hyperthermia.

A simple method to synthesize modified Fe3O4 for the removal of organic pollutants on water surface

In this article, a simple, economic and environment-friendly approach is explored to prepare Fe3O4 nanoparticles by using air oxidation at room temperature. Furthermore, the Fe3O4 magnetic nanoparticles (MNPs) have been modified with sodium oleate successfully to form super-hydrophobic surfaces. The alkali source played an important role in controlling the morphologies of Fe3O4 MNPs. Either Fe3O4 MNPs or sodium oleate modified Fe3O4 MNPs possessed good magnetic property, and the as-prepared modified Fe3O4 nanoparticles are both hydrophobic and lipophilic. Therefore, Fe3O4/sodium oleate could be dispersed stable in the oil medium and have been applied in the cleanup engine oil from the water surface. It will open up a potential and broad application in wastewater treatment.

Magnetite-loaded fluorine-containing polymeric micelles for magnetic resonance imaging and drug delivery

Magnetite (Fe3O4) – loaded polymer micelles (denoted as “magnetomicelles”) are produced by self-assembly of fluorine-containing amphiphilic poly(HFMA-g-PEGMA) copolymers with oleic acid modified Fe3O4 nanoparticles in an aqueous medium. The oleic acid modified Fe3O4 nanoparticles form small clusters in the poly(HFMA-g-PEGMA) micelles with a mean diameter of 100 nm and the magnetomicelles show high stability in an aqueous medium due to the high hydrophobic fluorine segments in graft copolymers enhance the stability of the micelles. The magnetomicelles also show good cytocompatibility based on the MTT cytotoxicity assay and possess paramagnetic properties with saturation magnetization of 17.14 emu/g.Their good stability, cytocompatibility, and paramagnetic properties render the materials attractive in drug delivery and in vivo magnetic resonance imaging (MRI) applications. Controlled release of hydrophobic drug-5-fluorouracil is achieved from the magnetomicelles with a loading efficiency of 20.94 wt%. The magnetomicelles have transverse relaxivity rates (r2) of 134.27 mM−1 s−1 and exhibit high efficacy as a negative MRI agent in T2-weighted imaging. In vivo MRI studies demonstrate that the contrast between liver and spleen is enhanced by the magnetomicelles. These favorable properties suggest clinical use as nanocarriers in drug delivery applications and contrast agents in MRI.

Progress in Organic Synthesis Reactions Catalyzed by Palladium Supported on Magnetic Nanoparticles

The organic synthesis reactions catalyzed by palladium supported on magnetic nanoparticles have attracted con- sideralbe attention because catalytic activity is excellent and supported catalyst can be separated easily with an external mag- net and reused several times. In this paper, the advances in the organic synthesis reactions catalyzed by palladium supported on magnetic nanoparticles have been reviewed. Fe3O4 nanoparticles, organic small molecles modified Fe3O4 nanoparticles, SiO2 modified Fe3O4 nanoparticles, carbon modified magnetic nanopartilces, hydroxyapatite modified magnetic nanopartilces and polymer modified magnetic nanopartilces were used to support the palladium catalysts. Keywords organic synthesis reactions; magnetic nanoparticles; supported palladium catalyst; catalysis

Synthesis and characterization of magnetic β-cyclodextrin–chitosan nanoparticles as nano-adsorbents for removal of methyl blue

A novel nano-adsorbent, β-cyclodextrin–chitosan (CDC) modified Fe3O4 nanoparticles (CDCM) is fabricated for removal of methyl blue (MB) from aqueous solution by grafting CDC onto the magnetite surface. The characteristics results of FTIR, SEM and XRD show that CDC is grafted onto Fe3O4 nanoparticles. The grafted CDC on the Fe3O4 nanoparticles contributes to an enhancement of the adsorption capacity because of the strong abilities of CDCM, which includes the multiple hydroxyl, carboxyl groups, amino groups and the formation of an inclusion complex due to the β-CD molecules through host–guest interactions, to adsorb MB. The adsorption of MB onto CDCM is found to be dependent on pH and temperature. Adsorption equilibrium is achieved in 50min and the adsorption kinetics of MB is found to follow a pseudo-second-order kinetic model. Equilibrium data for MB adsorption are fitted well by Langmuir isotherm model. The maximum adsorption capacity for MB is estimated to be 2.78g/g at 30°C. The CDCM was stable and easily recovered. Moreover the adsorption capacity was about 90% of the initial saturation adsorption capacity after being used four times.

Selective recognition and separation of nucleosides using carboxymethyl-β-cyclodextrin functionalized hybrid magnetic nanoparticles

A novel magnetic nanoadsorbent (CMCD-APTS-MNPs) containing the superparamagnetic and molecular recognition properties was synthesized by grafting carboxymethyl-β-cyclodextrin (CM-β-CD) on 3-aminopropyltriethoxysile (APTS) modified Fe3O4 nanoparticles. The feasibility of using CMCD-APTS-MNPs as magnetic nanoadsorbent for selective adsorption of adenosine (A) and guanosine (G) based on inclusion and molecular recognition was demonstrated. The as-synthesized magnetic nanoparticles were characterized by TEM, FTIR and TGA analyses. The effects of pH and initial nucleoside concentrations on the adsorption behavior were studied. The complexation of CMCD-APTS-MNPs with both nucleosides was found to follow the Langmuir adsorption isotherm. The CMCD-APTS-MNPs showed a higher adsorption ability and selectivity for G than A under identical experimental conditions, which results from the ability of selective binding and recognition of the immobilized CM-β-CD towards G. The driving force of the separation between G and A is through the different weak interaction with grafted CM-β-CD, i.e., hydrogen bond interaction, which is evidenced by different inclusion equilibrium constants and FTIR analyses of inclusion complexes between grafted cyclodextrin and the guest molecules. Our results indicated that this nanoadsorbent would be a promising tool for easy, fast and selective separation, analysis of nucleosides and nucleotides in biological samples.

Effect of surface modification of Fe3O4 nanoparticles on the preparation of Fe3O4/polystyrene composite particles via miniemulsion polymerization

Fe3O4 nanoparticles were modified by n-octadecyltrimethoxysilane (C18TMS) and 3-trimethoxysilylpropylmethacrylate (MPS). The modified Fe3O4 nanoparticles were used to prepare Fe3O4/polystyrene composite particles by miniemulsion polymerization. The effect of surface modification of Fe3O4 on the preparation of Fe3O4/polystyrene composite particles was investigated by transmission electron microscopy, Fourier transform infrared spectrophotometer (FT-IR), contact angle, and vibrating sample magnetometer (VSM). It was found that C18TMS modified Fe3O4 nanoparticles with high hydrophobic property lead to the negative effect on the preparation of the Fe3O4/polystyrene composite particles. The obtained composite particles exhibited asymmetric phase-separated structure and wide size distribution. Furthermore, un-encapsulated Fe3O4 were found in composite particles solution. MPS modified Fe3O4 nanoparticles showed poor hydrophobic properties and resulted in the obtained Fe3O4/polystyrene composite particles with regular morphology and narrow size distribution because the ended C=C of MPS on the surface of Fe3O4 nanoparticles could copolymerize with styrene which weakened the phase separation distinctly.

Immobilization of Metalloporphyrin on Functionalized Magnetic Nanoparticles as a Catalyst in Oxidation of Cyclohexene: Novel Modified Fe3O4 Nanoparticles with Triethoxysilane Agent

Magnetic nanoparticles, Fe3O4, have been prepared and functionalized by (N-(3-(triethoxysilyl)propyl)isonicotinamide) and characterized by infrared spectroscopy, thermal analysis (TGA/DTA), X-ray powder diffraction, scanning electron microscopy, elemental analysis and BET surface area measurement. The functionalized Fe3O4 nanoparticles were used as a support to anchor metalloporphyrin. Application of immobilized metalloporphyrin as a heterogeneous catalyst in the oxidation of cyclohexene was explored. Effect of various parameters such as solvent and temperature on immobilization process and also various parameters (solvent, time, oxidant and axial group effect) on oxidation of cyclohexene has been investigated. The result showed that the immobilized metalloporphyrin on functionalized magnetic nanoparticles is an efficient and reusable catalyst for oxidation of cyclohexene.

In situ Production of Polystyrene Magnetic Nanocomposites through a Batch Suspension Polymerization Process

AbstractThis work presents the synthesis of micro‐sized polystyrene magnetic beads by in situ incorporation of oleic acid‐modified Fe3O4 magnetic nanoparticles via a suspension polymerization process. Fe3O4 nanoparticles with superparamagnetic characteristics were obtained through a coprecipitation technique. These particles present an average diameter equal to 7.4 ± 4.6 nm, as determined by AFM. This result is in agreement with the crystallite size of single domains calculated by using Scherrer's equation, which was equal to 7.7 nm, based on XRD measurements. The obtained materials were also studied using TGA. The weight loss behavior was independent of the Fe3O4 content and the stability to the thermal degradation was also not improved by magnetic nanoparticles present in the composite. Polystyrene/Fe3O4 magnetic nanocomposites exhibited the same diffraction peaks observed in the pure Fe3O4, which indicates that nanoparticles inside the composites preserved the structure and properties of pure Fe3O4. It was also shown that nanosized polystyrene particles, dispersed in the aqueous phase, are obtained due to the stabilization effect of the oleic acid on the styrene droplets. A cross‐section of polystyrene magnetic particles showed empty spherical regions, attributed to the encapsulation of water microdroplets during the polymerization reaction. The obtained polymeric materials also presented good magnetic behavior, indicating that the modified Fe3O4 nanoparticles were successfully dispersed in the polystyrene particles.magnified image

Preparation of superparamagnetic polyaniline hybrid hollow microspheres in oil/water emulsion with magnetic nanoparticles as cosurfactant

A novel strategy was developed to prepare the superparamagnetic polyaniline (PANI) hybrid hollow microspheres via the combination of the interfacial polymerization and Pickering emulsion techniques in oil/water (O/W) emulsion, with the sodium citrate modified Fe3O4 nanoparticles (Fe3O4-CA) as cosurfactant and dopant. The effect of the feeding amount of the sodium citrate modified Fe3O4 nanoparticles (Fe3O4-CA) on the formation of the sodium citrate modified Fe3O4/polyaniline hybrid hollow microspheres (Fe3O4-CA/PANI) was investigated. When the feeding ratio between the sodium citrate modified Fe3O4 nanoparticles (Fe3O4-CA) and aniline reached 1.50, the intact Fe3O4-CA/PANI hybrid hollow microspheres were obtained with high yield and regularity. The diameter of the hybrid hollow microspheres was about 500nm from the transmission electron microscopy (TEM) analysis. The Fe3O4-CA nanoparticles appeared to increase the stability of the oil droplets during the polymerization and improve the electrical conductivity of the hybrid hollow microspheres.

Determination aminopyrine in pharmaceutical formulations based on APTS-Fe3O4 nanoparticles modified glassy carbon electrode

In this work, 3-aminopropyltriethoxysilane modified Fe3O4 nanoparticles (ATPS-Fe3O4) were used to modify glassy carbon electrode for aminopyrine determination. ATPS-Fe3O4 showed obviously catalytic activity and adsorptivity towards aminopyrine oxidation proven by the increased oxidation peak current and the decreased oxidation peak potential. The best analytical response was obtained by immobilizing 8 μL 3 mg/mL APTS-Fe3O4 dispersion with an accumulation time of 200 s at −0.2 V in 0.1 M phosphate buffer solution (pH 9.0). The oxidation peak current of aminopyrine showed linear relationship with its concentration in the range from 0.5 to 100 and 100 to 1600 μM. The detection limit was 0.1 μM (S/N = 3). The proposed method showed satisfactory repeatability and anti-interference ability. The fabricated electrode was successfully applied to determine aminopyrine in pharmaceutical formulations.

Removal of methyl orange from aqueous solution by Azolla filicoloides: Synthesis of Fe3O4 nano-particles and its surface modification by the extracted pectin of Azolla

Abstract The modified Fe3O4 nano-particles with the extracted pectin from the cell wall of Azolla filicoloides (FN-EP) can remove methyl orange as a water-soluble azo dye from waste water better than Azolla and the extracted pectin from Azolla (EPA), alone. It could be due to more crowding the main functional groups of uptake after binding pectin with nano-particles. Thermodynamic studies showed that adsorption equilibrium constant (KL) and maximum adsorption capacities (Qmax) were increased with decreasing temperature (exothermic). The maximum uptake capacity (Qmax) of dye by FN-EP in a batch reactor was 0.533, 0.498 and 0.446 mmol/g at 5, 25 and 50 °C, respectively. The enthalpy change (ΔH) and entropy change (ΔS) were −15.31 kJ/mol and −0.02434 kJ/mol K, respectively.

Gum arabic modified Fe3O4 nanoparticles cross linked with collagen for isolation of bacteria

BackgroundMultifunctional magnetic nanoparticles are important class of materials in the field of nanobiotechnology, as it is an emerging area of research for material science and molecular biology researchers. One of the various methods to obtain multifunctional nanomaterials, molecular functionalization by attaching organic functional groups to nanomagnetic materials is an important technique. Recently, functionalized magnetic nanoparticles have been demonstrated to be useful in isolation/detection of dangerous pathogens (bacteria/viruses) for human life. Iron (Fe) based material especially FePt is used in the isolation of ultralow concentrations (< 102 cfu/ml) of bacteria in less time and it has been demonstrated that van-FePt may be used as an alternative fast detection technique with respect to conventional polymerase chain reaction (PCR) method. However, still further improved demonstrations are necessary with interest to biocompatibility and green chemistry. Herein, we report the synthesis of Fe3O4 nanoparticles by template medication and its application for the detection/isolation of S. aureus bacteria.ResultsThe reduction of anhydrous Iron chloride (FeCl3) in presence of sodium borohydride and water soluble polyelectrolyte (polydiallyldimethyl ammonium chloride, PDADMAC) produces black precipitates. The X-ray diffraction (XRD), XPS and TEM analysis of the precipitates dried at 373 K demonstrated the formation of nanocrystalline Fe3O4. Moreover, scanning electron microscopy (SEM) showed isolated staphylococcous aureus (S. aureus) bacteria at ultralow concentrations using collagen coated gum arabic modified iron oxide nanoparticles (CCGAMION).ConclusionWe are able to synthesize nanocrystalline Fe3O4 and CCGAMION was able to isolate S. aureus bacteria at 8-10 cfu (colony forming units)/ml within ~3 minutes.

Preparation and characterization of cross-linked β-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures

Abstract Cross-linked β-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethyl β-cyclodextrin (CM-β-CD) modified Fe3O4 nanoparticles in β-cyclodextrin alkaline solution by using epichlorohydrin as crosslinking agent. The morphology, structure and magnetic properties of the prepared composite nanoparticles were investigated by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectrometry, X-ray diffraction (XRD) measurement, thermogravimetric analysis (TGA) and Vibrating sample magnetometry (VSM), respectively.

Preparation of SiO&lt;SUB&gt;2&lt;/SUB&gt;/(PMMA/Fe&lt;SUB&gt;3&lt;/SUB&gt;O&lt;SUB&gt;4&lt;/SUB&gt;) from Monolayer Linolenic Acid Modified Fe&lt;SUB&gt;3&lt;/SUB&gt;O&lt;SUB&gt;4&lt;/SUB&gt; Nanoparticles via Miniemulsion Polymerization

SiO2/(PMMA/Fe3O4) composite particles were prepared from linolenic acid (LA) instead of oleic acid (OA) modified Fe3O4 nanoparticles by miniemulsion polymerization. LA has three unsaturated double bonds with which it can polymerizate more easily than OA. And coating Fe3O4 with polymethyl methacrylate (PMMA) polymer beforehand can prevent magnetic nanoparticles from the aggregation that usually comes from the increasing of ionic strength during the hydrolyzation of tetraethoxysilane (TEOS) by the steric hindrance. Finally, the resulting PMMA/Fe3O4 nanoparticles were coated with silica, forming SiO2/(PMMA/Fe3O4) core-shell structure particles. The sizes of nanoparticles with core-shell structure were in the range from 300 to 600 nm. The nanoparticles were spherical particles and had consistent size. The result of magnetic measurement showed that the composite particles had superparamagnetic property.

Preparation and characterization of Fe3O4 magnetic composite microspheres covered by a P(MAH-co-MAA) copolymer

A magnetic core–shell-layered polymer microsphere (MPS) was successfully synthesized by a dispersion polymerization route, where the modified Fe3O4 nanoparticles (MFN) were used as a core, while poly(maleic anhydride-co-methacrylic acid) P(MAH-co-MAA) as a shell was covered on the surface of the Fe3O4 nanoparticles. Environmental scanning electron microscope (ESME) and transmission electron microscope (TEM) measurements indicate that the magnetic P(MAH-co-MAA)/Fe3O4 composite microspheres assume sphericity and have a novel core–shell-layered structure. The crystal particle sizes of the unimproved Fe3O4 and the MFN samples vary from 8 to 16 nm in diameter, and the average size is about 10.6 nm in diameter. The core–shell magnetic composite microspheres can be adjusted by changing the stirring speed. Since multiple Fe3O4 cores were coated with a proper percentage of P(MAH-co-MAA) copolymers, and therefore lower density was acquired for the MPS, which improved sedimentation and dispersion behavior. The saturated magnetization of pure Fe3O4 nanoparticles reaches 48.1 emu g−1 and the value for composite nanoparticles was as high as 173.5 emu g−1. The nanoparticles show strong superparamagnetic characteristics and can be expected to be used as a candidate for magnetism-controlled drug release.

Nanocomposite particles with core‐shell morphology. I. Preparation and characterization of Fe3O4–poly(butyl acrylate‐styrene) particles via miniemulsion polymerization

AbstractColloidal particles with magnetic properties have become increasingly important both technologically and for fundamental studies. Here, chemical initiator‐free miniemulsion polymerization of styrene and butyl acrylate has been performed for preparation of magnetic nanocomposite particles with the diameter of 81–150 nm in the presence of sodium dodecyl sulfate as surfactant, span 80 as stabilizer, and hexadecane as hydrophobe. The polymerization reaction was initiated and progressed under ultrasonic irradiation, generated by immersed probe into the latex. The key point in achievement of encapsulation of modified Fe3O4 nanoparticles was preparation of a stable colloidal dispersion at the end of the reaction. The obtained products in each step were characterized by FTIR spectroscopy. Dynamic light scattering analysis was used to follow particle size diameter of the samples. Morphology of the particles and formation of core‐shell structure were analyzed by SEM and TEM micrographs, respectively. TGA and magnetometry of the polymeric films confirmed the extent of insertion of used magnetite and their corresponding behavior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Preparation of Fe3O4/polystyrene composite particles from monolayer oleic acid modified Fe3O4 nanoparticles via miniemulsion polymerization

Fe3O4/polystyrene composite particles were prepared from oleic acid (OA) modified Fe3O4 nanoparticles via miniemulsion polymerization. It was concluded that the surface properties of OA modified magnetite nanoparticles have a great effect on preparation of the composite particles. When Fe3O4 nanoparticles coated by multilayer of OA was employed, there were large amounts of free polystyrene particles in the product. Fe3O4/polystyrene composite particles with defined structure and different magnetite content can be readily prepared from monolayer OA modified Fe3O4 nanoparticles. It was concluded that surface of the monolayer OA modified Fe3O4 nanoparticles is more hydrophobic than that of the multilayer coated ones, thus improving the dispersibility of the Fe3O4 nanoparticles in styrene monomer and allowing preparation of the Fe3O4/polystyrene composite particles with defined structure and controllable magnetite content.