Photodegradation of 2-mercaptobenzothiazole in the gamma-Fe(2)O(3)/oxalate suspension under UVA light irradiation

The aim of this study is to investigate the effect of various factors on the photodegradation of organic pollutants in natural environment with co-existence of iron oxides and oxalic acid. 2-Mercaptobenzothiazole (MBT) was selected as a model pollutant, while gamma-Fe(2)O(3) was selected as iron oxide. The crystal structure and morphology of the prepared gamma-Fe(2)O(3) was determined by X-ray diffractograms (XRD) and scanning electron microscopy (SEM), respectively. The specific surface area was 14.36 m(2)/g by Brunauer-Emmett-Teller (BET) method. The adsorption behavior of gamma-Fe(2)O(3) was evaluated by Langmuir model. The effect of the dosage of iron oxide, initial concentration of oxalic acid (C(ox)(0)), initial pH value, the light intensity and additional transition metal cations on MBT photodegradation was investigated in the gamma-Fe(2)O(3)/oxalate suspension under UVA light irradiation. The optimal gamma-Fe(2)O(3) dosage was 0.4 g/L and the optimal C(ox)(0) was 0.8 mM with the UVA light intensity of 1800 mW/cm(2). And the optimal dosage of gamma-Fe(2)O(3) and C(ox)(0) for MBT degradation also depended strongly on the light intensity. The optimal gamma-Fe(2)O(3) dosage was 0.1, 0.25 and 0.4 g/L, and the optimal C(ox)(0) was 1.0, 0.8, and 0.8 mM with the light intensity of 600, 1200 and 1800 mW/cm(2), respectively. The optimal initial pH value was at 3.0. The additional transition metal cations including Cu(2+), Ni(2+) or Mn(2+) could significantly accelerate MBT degradation. This investigation will give a new insight to understanding the MBT photodegradation in natural environment.     

Surface modification of gamma-Fe2O3@SiO2 magnetic nanoparticles for the controlled interaction with biomolecules

Modifying the surface of magnetic nanoparticles (MNPs) to allow for controlled interaction with biomolecules enables their implementation in biomedical applications such as contrast agents for magnetic resonance imaging, labels in magnetic biosensing or media for magnetically assisted bioseparation. In this paper, self-assembly of trialkoxysilanes is used to chemically functionalize the surface of gamma-Fe2O3@SiO2 core-shell particles. First, the silane deposition procedure was optimized using infrared analysis in order to obtain maximum packing density of the silanes on the particles. The surface coverage was determined to be approximately 8 x 10(14) molecules/cm2. It was shown that the magnetic, crystalline, and morphological properties of the MNPs were not altered by deposition of a thin silane coating. The optimized procedure was transferred for the deposition of aldehyde and poly(ethylene glycol) (PEG) presenting silanes. The presence of both silanes on the particle surface was confirmed using XPS and FTIR. The interaction of proteins with silane-modified MNPs was monitored using a Bradford protein assay. Our results demonstrate that, by introducing aldehyde functions, the MNPs are capable of covalently binding human IgG while retaining their specific binding capacity. Maximum surface coverage occurs at 46 microg antibodies per mg particle, which corresponds to 35 antibodies bound to an average sized MNP (54 nm in diameter). The human IgG functionalized MNPs exhibit a high degree of specificity (approximately 90%) and retained a binding capacity of 32%. Using the same approach, streptavidin was coupled onto the MNPs and the biotin binding capacity was determined using biotinylated fluorescein. At maximum surface coverage, a biotin binding capacity of 1500 pmol/mg was obtained, corresponding to a streptavidin activity of 76%. On the other hand, by introducing PEG functions the non-specific adsorption of serum proteins could be significantly suppressed down to approximately 3 microg/mg. We conclude that self-assembly of silane films creates a generic platform for the controlled interactions of MNPs with biomolecules.     

Synthesis of Fe-group metal oxide nanostructures by thermal oxidation and their magnetic properties

In this paper, we review the preparation of Fe-group metal oxide nanostructures by the thermal oxidation method developed in our lab. By this method, we have prepared several kinds of nanostructures, including nanowires and nanoleaves. The magnetic properties of these nanostructures have also been studied. By carefully controlling the reacting time, temperature, and humidity, we have prepared alpha-Fe2O3, gamma-Fe2O3, Fe3O4, and Co3O4 nanowires and alpha-Fe2O3 nanoleaves by heating the substrates in proper atmosphere. The alpha-Fe2O3 and Co3O4 nanowires are produced by directly oxygenating pure metal at 550 to approximately 650 degrees C and 480-520 degrees C, separately. The gamma-Fe2O3 and Fe3O4 nanowires are produced by reducing as-prepared alpha-Fe2O3 nanowires in a mixture of N2 and H2. The nanowires are about 10-20 microm, with diameter of about 20 to approximately 100 nm. Most of the nanowire arrays are grown vertically from the surface of the substrate at a high surface density (10(8)-10(9) cm(-2)). Compared with the nanowires prepared by hydrothermal process and template method, Most of our nanowires are structurally uniform and single crystallites. The magnetic properties of these nanostructures are also studied, and demonstrate some novel properties.     

Conditions of polymerase chain reaction amplification by magnetic enrichment and nanoscale detection sensitivity

In this research, we reported a method of polymerase chain reaction (PCR) amplification by means of magnetic enrichment. First, after denaturation, the target sequence was combined with biotin-modified specific primer through hybridization and enriched at the surface of gamma-Fe2O3 by biotin-avidin special interaction. Then single target sequence was gained through denaturation, and general PCR amplification was performed. The experiment conditions such as the hybridization temperature between target sequence and biotin-modified specific primer, and the dosage of magnetic nanoparticles gamma-Fe2O3 were optimized. Finally, the sensitivity of the method was checked. The lowest concentration of target sequence was detected as low as 5 x 10(-7) ng/mL. This simple method could provide a quick and early diagnosis of malignant infectious diseases such as SARS, avian flu and swine flu etc., that occur occasionally nowadays.     

Polymerase chain reaction coupling with magnetic nanoparticles-based biotin-avidin system for amplification of chemiluminescent detection signals of nucleic acid

A novel method was established through the detection of chemiluminescent signals of nucleic acid hybridization based on magnetic nanoparticles (MNPs) and PCR. 5' amino- modified specific probes were immobilized on the surface of silanized MNPs by Schiff reaction between amino and aldehyde group. The probes were used to capture the synthetic biotin-dUTP-labeled DNA fragments which were obtained by polymerase chain reaction (PCR). Then these complexes were bonded with streptavidin-modified alkaline phosphatase (SA-AP). Finally the chemiluminescent signals were detected by adding 3-(2'-spiroadamantane)- 4-methoxy -4-(3"-phosphoryloxy) phenyl-1, 2-dioxetane (AMPPD) which was the substrate reagent of AP. The concentration of probes which were immobilized on the surface of MNPs was studied, how to reduce the adsorption of SA-AP on the surface of MNPs was also researched. It was shown that 12.5 pmol of probes were immobilized on 1 mg of MNPs. Aldehyde-MNPs modified with probes could adsorb SA-AP, affecting the sensitivity of chemiluminescene consequently. Reduction of aldehyde group by sodium borohydride and blocking the bare position of MNPs with bovine serum albumin (BSA) could decrease the background of chemiluminescence, and this method has good specificity in detection of chloramphenicol acetyltransferase (CAT) gene.     

Glutaraldehyde mediated conjugation of amino-coated magnetic nanoparticles with albumin protein for nanothermotherapy

A novel bioconjugation of amino saline capped Fe3O4 magnetic nanoparticles (MNPs) with bovine serum albumin (BSA) was developed by applying glutaraldehyde as activator. Briefly, Fe3O4 MNs were synthesized by the chemical co-precipitation method. Surface modification of the prepared MNPs was performed by employing amino saline as the coating agent. Glutaraldehyde was further applied as an activation agent through which BSA was conjugated to the amino-coated MNPs. The structure of the BSA-MNs was confirmed by FTIR analysis. Physico-chemical characterizations of the BSA-MNPs, such as surface morphology, surface charge and magnetic properties were investigated by Transmission Electron Microscopy (TEM), zeta-Potential and Vibrating Sample Magnetometer (VSM), etc. Magnetic inductive heating characteristics of the BSA-MNPs were analyzed by exposing the MNPs suspension (magnetic fluid) under alternative magnetic field (AMF). The results demonstrate that BSA was successfully conjugated with amino-coated MNs mediated through glutaraldehyde activation. The nanoparticles were spherical shaped with approximately 10 nm diameter. Possessing ideal magnetic inductive heating characteristics, which can generate very rapid and efficient heating while upon AMF exposure, BSA-MNPs can be applied as a novel candidature for magnetic nanothermotherapy for cancer treatment. In vitro cytotoxicity study on the human hepatocellular liver carcinoma cells (HepG-2) indicates that BSA-MNP is an efficient agent for cancer nanothermotherapy with satisfied biocompatibility, as rare cytotoxicity was observed in the absence of AMF. Moreover, our investigation provides a methodology for fabrication protein conjugated MNPs, for instance monoclonal antibody conjugated MNPs for targeting cancer nanothermotherapy.     

Fe3O4 magnetic nanoparticles as peroxidase mimetics and their applications in H2O2 and glucose detection

Artificial enzyme mimetics are a current research interest because natural enzymes bear some serious disadvantages, such as their catalytic activity can be easily inhibited and they can be digested by proteases. A very recently study reported by Yan et al. has proven that Fe(3)O(4) magnetic nanoparticles (MNPs) exhibit an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, though MNPs are usually thought to be biological and chemical inert (Gao, L. Z.; Zhuang, J.; Nie, L.; Zhang, J. B.; Zhang, Y.; Gu, N.; Wang, T. H.; Feng, J.; Yang, D. L.; Perrett, S.; Yan, X. Y. Nat. Nanotechnol. 2007, 2, 577-583). In the present work, we just make use of the novel properties of Fe(3)O(4) MNPs as peroxidase mimetics reported by Yan et al. to detect H(2)O(2). The Fe(3)O(4) MNPs were prepared via a coprecipitation method. The as-prepared Fe(3)O(4) MNPs were then used to catalyze the oxidation of a peroxidase substrate 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) by H(2)O(2) to the oxidized colored product (see eq 1) which provides a colorimetric detection of H(2)O(2). As low as 3 x 10(-6) mol/L H(2)O(2) could be detected with a linear range from 5 x 10(-6) to 1 x 10(-4) mol/L via our method. More importantly, a sensitive and selective method for glucose detection was developed using glucose oxidase (GOx) and the as-prepared Fe(3)O(4) MNPs. The detection platforms for H(2)O(2) and glucose developed in the present work not only further confirmed that the Fe(3)O(4) MNPs possess intrinsic peroxidase-like activity but also showed great potential applications in varieties of simple, robust, and easy-to-make analytical approaches in the future.     

A novel magnetic nanoparticle hyperthermia combined with ACMF-dependant drug release by DAMMs injection in VX-2 liver tumors

In this paper, we investigated the feasibility and effect of a novel combination therapy of magnetic nanoparticles (MNPs) hyperthermia with anticancer drugs for solid malignancies using doxorubicin-loaded alginate-templated magnetic microcapsules (DAMMs) in an animal liver cancer model. Firstly, DAMMs containing 18 nm gamma-Fe2O3 with doxorubicin (Dox) were synthesized and characterized. Then, the particular behavior of Dox release under external alternating current magnetic filed (ACMF) was tested in vitro. Moreover, to obtain accurate thermotherapy, the dose of DAMMs and temperature rise were computed by Hyperthermia treatment plan (HTP) and a fiber optic temperature sensor (FOTS) was used to monitor the temperature rise during treatments on VX-2 liver tumor-bearing rabbits. Furthermore, the therapeutic effect was studied by histopathological examinations and animal survival. The results showed that ACMF can induce Dox fast release during the treatment and the high MNPs content of DMMAs guaranteed the temperature rise for hyperthermia in tumors. The rabbits bearing VX-2 tumors in the magnetic hyperthermia using DMMAs group gained the most tumor necrosis and survival time. It was indicated that DAMMs-based magnetic hyperthermia could be a feasible and effective remedy which could be targeted at liver tumors by dual effects of hyperthermia and chemotherapy.     

Preparation of SiO2/(PMMA/Fe3O4) nanoparticles using linolenic acid as crosslink agent for nucleic acid detection using chemiluminescent method

Usually, magnetic nanoparticles (MNPs) are prepared based on the famous St?ber process in which divinylbenzene (DVA) is often used as a crosslink agent to synthesize SiO2/(PMMA/Fe3O4) nanoparticles. Compared with DVA, linolenic acid (LNA) is innoxious and can polymerize more easily for it has three unsaturated double bonds. In this paper, LNA was used as a new crosslink agent instead of DVA to synthesize the SiO2/(PMMA/Fe3O4) nanoparticles. The results showed that the core-shell structure could be observed obviously. The sizes of nanoparticles with core-shell structure range from 200 to 500 nm. The DNA probes which was immobilized on the surface of MNPs were used to capture the biotin modified complementary sequence of the probe, and the formed complexes were bonded with streptavidin-modified alkaline phosphatase (SA-AP). Finally the chemiluminescent signals were detected by adding 3-(2'-spiroadamantane)-4-methoxy-4-(3"-phosphoryloxy) phenyl-1, 2-dioxetane (AMPPD) which was the substrate reagent of AP. The specificity and sensitivity of this approach were investigated in this paper.     

Synthesis and characterization of bicalutamide-loaded magnetic nanoparticles as anti-tumor drug carriers

This study examined the optical characteristics of bicalutamide-loaded magnetic/ethylene glycol composite nanoparticles (BMP), as well as their anti-cancer activity against cancer cells. The gamma-Fe2O3 magnetic nanoparticles (MNPs), approximately 20 nm in diameter, were prepared via a chemical co-precipitation method and coated with two surfactants to yield a water-based product. The characteristics of the particles were determined via X-ray diffraction (XRD), field emission scanning electron microscopy, and Raman spectrophotometry. The Raman spectra of the BMP showed peaks at 222, 283, 395, 520, 669 and 1316 cm(-1), with broadened band in comparison to the Raman spectra of the magnetic nanoparticles. The BMP absorbance evidenced a rapid increase, with a broad peak at 409 nm, thus reflecting a good loading of the bicalutamide onto the magnetic nanoparticles. The results of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the MNPs were non-toxic against human brain cancer cells (SH-SY5Y), human cervical cancer cells (Hela), human liver cancer cells (HepG2), breast cancer cells (MCF-7), colon cancer cells (CaCO2) and human prostate cancers (Du 145, PC3) tested herein. In particular, BMPs were cytotoxic at 56% against DU145 cells, at 74.37% in SH-SY5Y cells, and at 58% in Hela cells. Our results demonstrated the biological applicability of BMP nanoparticles as anticancer agents and as agents for enhanced drug delivery against human prostate cancer cells. Our results indicated that the MNPs were biostable and that the BMP functioned effectively as drug delivery vehicles.     

Synthesis and characterisation of polyol-capped transition metal oxide nanoparticles

In-situ capped nanocrystalline gamma-Fe2O3, Co3O4, and Cu2O were prepared in 1,4-butanediol in aerobic conditions. X-ray diffraction (XRD) patterns show that the synthesised samples are nanocrystalline cubic oxides with crystallite sizes 9.5 nm, 13.4 nm, and 11 nm, respectively. Raman spectroscopy shows peaks at 350 cm(-1), 500 cm(-1), and 700 cm(-1), indicating that the iron oxide is gamma-Fe2O3; M?ssbauer spectroscopy shows the presence of two Fe3(3+) sites. Transmission electron microscopy images show that the particle sizes of gamma-Fe2O3 and Co3O4 samples are 8.9 nm and 7 nm, respectively. The absence of agglomeration indicates that the synthesised nanoparticles are capped. FT-IR spectra show the presence of an organic moiety in the sample which acts as a capping agent. Thermogravimetry shows that the capping is stable up to 873 K in gamma-Fe2O3, and up to 400 K in Co3O4. The samples are soluble in water to form stable hydrosols. During synthesis of gamma-Fe2O3 a 6-line ferrihydrite is formed as an intermediate, which is stable in solution up to 473 K, and transforms to gamma-Fe2O3 at 483 K, by rapid dissolution-reprecipitation. In the syntheses of Co3O4 and Cu2O, no intermediates are formed.     

Fabrication of a glucose biosensor based on citric acid assisted cobalt ferrite magnetic nanoparticles

A novel and practical glucose biosensor was fabricated with immobilization of Glucose oxidase (GOx) enzyme on the surface of citric acid (CA) assisted cobalt ferrite (CF) magnetic nanoparticles (MNPs). This innovative sensor was constructed with glassy carbon electrode which is represented as (GOx)/CA-CF/(GCE). An explicit high negative zeta potential value (-22.4 mV at pH 7.0) was observed on the surface of CA-CF MNPs. Our sensor works on the principle of detection of H2O2 which is produced by the enzymatic oxidation of glucose to gluconic acid. This sensor has tremendous potential for application in glucose biosensing due to the higher sensitivity 2.5 microA/cm2-mM and substantial increment of the anodic peak current from 0.2 microA to 10.5 microA.     

Photocatalytic degradation of azo dyes using Au:TiO2, gamma-Fe2O3:TiO2 functional nanosystems

We report photocatalytic degradation studies on Navy Blue HE2R (NB) dye on significant details as a representative from the class of azo dyes using functional nanosystems specifically designed to allow a strong photocatalytic activity. A modified sol-gel route was employed to synthesize Au and gamma-Fe2O3 modified TiO2 nanoparticles (NPs) at low temperature. The attachment strategy is better because it allows clear surface of TiO2 to remain open for photo-catalysis. X-ray diffraction, Raman and UV-VIS spectroscopy studies showed the presence of gold and iron oxide phases along-with the anatase TiO2 phase. TEM studies showed TiO2 nanocomposite particles of size approximately 10-12 nm. A detailed investigation on heterogeneous photocatalytic performance for Navy Blue HE2R dye was done using the as-synthesized catalysts Au:TiO2 and gamma-Fe2O3:TiO2 in aqueous suspension under 8 W low-pressure mercury vapour lamp irradiation. Also, the photocatalytic degradation of Amranth and Orange G azo dyes were studied. The surface modified TiO2 NPs showed significantly improved photocatalytic activity as compared to pure TiO2. Exposure of the dye to the UV light in the presence of pure and gold NPs attached TiO2 catalysts caused dye degradation of about approximately 20% and approximately 80%, respectively, in the first couple of hours. In the presence of gamma-Fe2O3 NPs attached TiO2, a remarkable approximately 95% degradation of the azo dye was observed only in the first 15 min of UV exposure. The process parameters for the optimum catalytic activity are established which lead to a complete decoloration and substantial dye degradation, supported by the values of the Chemical Oxygen Demand (COD) approximately 93% and Total Organic Carbon (TOC) approximately 65% of the treated dye solution after 5 hours on the employment of the UV/Au:TiO2/H2O2 photocatalytic process.     

Novel active heterogeneous Fenton system based on Fe3-xMxO4 (Fe, Co, Mn, Ni): the role of M2+ species on the reactivity towards H2O2 reactions

In this work, the effect of incorporation of M2+ species, i.e. Co2+, Mn2+ and Ni2+, into the magnetite structure to increase the reactivity towards H2O2 reactions was investigated. The following magnetites Fe3-xMnxO4, Fe3-xCoxO4 and Fe3-xNixO4 and the iron oxides Fe3O4, gamma-Fe2O3 and alpha-Fe2O3 were prepared and characterized by M?ssbauer spectroscopy, XRD, BET surface area, magnetization and chemical analyses. The obtained results showed that the M2+ species at the octahedral site in the magnetite strongly affects the reactivity towards H2O2, i.e. (i) the peroxide decomposition to O2 and (ii) the oxidation of organic molecules, such as the dye methylene blue and chlorobenzene in aqueous medium. Experiments with maghemite, gamma-Fe2O3 and hematite, alpha-Fe2O3, showed very low activities compared to Fe3O4, suggesting that the presence of Fe2+ in the oxide plays an important role for the activation of H2O2. The presence of Co or Mn in the magnetite structure produced a remarkable increase in the reactivity, whereas Ni inhibited the H2O2 reactions. The obtained results suggest a surface initiated reaction involving Msurf2+ (Fe, Co or Mn), producing HO radicals, which can lead to two competitive reactions, i.e. the decomposition of H2O2 or the oxidation of organics present in the aqueous medium. The unique effect of Co and Mn is discussed in terms of the thermodynamically favorable Cosurf3+ and Mnsurf3+ reduction by Femagnetite2+ regenerating the active species M2+.     

Preparation and characterization of iminodiacetic acid-functionalized magnetic nanoparticles and its selective removal of bovine hemoglobin

In this study, a novel route for the preparation of magnetite (Fe(3)O(4)) nanoparticles (NPs) with immobilized metal affinity ligand iminodiacetic acid (IDA) charged with Cu(2+) was developed. First, magnetite nanoparticles were synthesized by a hydrothermal method. Charged with Cu(2+), the magnetic nanoparticles (MNPs) were applied to separate a model protein mixture of bovine hemoglobin (BHb) and bovine serum albumin (BSA). They could be separated completely and showed low non-specific adsorption. The morphology, structure and composition of the magnetite MNPs were characterized by transmission electron microscopy, power x-ray diffraction, x-ray photoelectron spectrometry and Fourier transform infrared spectroscopy. The resulting magnetite MNPs charged with Cu(2+) show not only a strong magnetic response to externally applied magnetic field, but are also highly specific to protein BHb. It is interesting that MNPs modified with metal ligands showed a property of magnetic colloid photonic crystals. Furthermore, they could efficiently remove the abundant protein bovine hemoglobin from bovine blood. They have potential application in removing abundant protein in proteomic analysis.     

The reactivity of ethylene oxide in contact with iron oxide fines as measured by adiabatic calorimetry

Samples of various iron oxides suspended above ethylene oxide in an adiabatic calorimeter exhibit exothermic activity at temperatures as low as room temperature. A gamma-Fe(2)O(3) sample was found to show the highest reactivity with ethylene oxide. Ethylene oxide in combination with most of the iron oxide fines tested displayed exothermic activity below 100 degrees C. Self-heat rates near 2000 degrees C/min were observed for the gamma-Fe(2)O(3) fines while rates in excess of 100 degrees C/min were found for other fines (alpha-Fe(2)O(3) and hydrated alpha-Fe(2)O(3)). In two cases (alpha-Fe(3)O(4) and alpha-Fe(2)O(3)), pressurization rates above 1000 psi/min took place. No reactivity was observed for ethylene oxide with the FeO. Thermal inertia effects in commercial operation, such as heat uptake by the equipment to which fines are attached, are presumed to be a factor in limiting the occurrence of related exotherms in ethylene oxide manufacturing facilities.     

Colorimetric detection of urine glucose based ZnFe2O4 magnetic nanoparticles

In this paper, we discovered that ZnFe(2)O(4) magnetic nanoparticles (MNPs) possess intrinsic peroxidase-like activity. ZnFe(2)O(4) MNPs exhibit several advantages such as high catalytic efficiency, good stability, monodispersion, and rapid separation over other peroxidase nanomimetics and horseradish peroxidase (HRP). ZnFe(2)O(4) MNPs were used as a colorimetric biosensor for the detection of urine glucose. This method is simple, inexpensive, highly sensitive, and selective for glucose detection using glucose oxidase (GOx) and ZnFe(2)O(4) MNPs with a linear range from 1.25 × 10(-6) to 1.875 × 10(-5) mol L(-1) with a detection limit of 3.0 × 10(-7) mol L(-1). The color change observable by the naked eyes based on the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) is the principle for the sensing of urine glucose level.     

Perpendicular magnetization in self-assembled films of citrate-capped gamma-Fe2O3 nanocrystals on Si(100) surfaces

gamma-Fe2O3 nanocrystals capped with citrate and octylamine have been chemically prepared. The octylamine-capped nanocrystals exhibit a tendency to form ordered lattices. Films of nanocrystals of varying thickness (454, 720, and 1400 microg/cm2 in the case of citrate-capped nanocrystals and 300 microg/cm2 in the case of octylamine-capped nanocrystals) have been prepared on Si(100) substrates by drop casting and have been characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. Magnetic measurements have been carried out on the films as well as on nanocrystal powders. The films of citrate-capped gamma-Fe2O3 nanocrystals exhibit enhanced perpendicular magnetization, with the anisotropy depending on the film thickness.     

Synthesis and characterization of uncapped gamma-Fe2O3 nanoparticles prepared by flame pyrolysis of ferrocene in ethanol

Nanoparticles of iron(III) oxide were synthesized by spontaneous combustion of ferrocene in ethanol solution using a simple spirit lamp. X-ray powder diffraction and electron diffraction analysis of the powder suggested the formation of gamma-Fe2O3 (Maghemite phase) having lattice constant 8.3539 +/- 0.0209 A. Transmission Electron Micrograph suggested the formation of spherical particles with an average diameter of 24.7 +/- 1.6 nm. A sextet with an isomeric shift of 0.328 mm s(-1) seen in the Mossbauer spectrum recorded at room temperature, further supports the formation of gamma-Fe2O3. The particles were dispersed freely in the polar solvents like ethanol, dimethyl sulfoxide, and water. Infra Red spectrum gave bands at 400, 432, 565, and 638 cm(-1), which confirms the presence of gamma-Fe2O3 phase.     

Synthesis and characterization of multifunctional iron oxide nanoparticles

In order to get high water solubility, monodisperse, superparamagnetic nanoparticles, poly (acrylic acid) was employed to modify Fe3O4 by a high-temperature solution-phase hydrolysis approach. Then, folic acid (FA) and fluorescein isothiocyanate were successively conjugated with prepared magnetic nanoparticles (MNPs). The functional MNPs were characterized by X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscope (TEM), inductively coupled plasma-atomic emission spectrometer (ICP-AES), and vibrating sample magnetometer (VSM), respectively. The toxicity of the materials was evaluated by selecting NIH/3T3 fibroblast cells and no toxic effect was observed. The fluorescent imaging and targeting property of the MNPs were also realized in vitro and in vivo experiments by confocal laser scanning microscopy (CLSM) and Kodak In-Vivo FX Professional Imaging System, respectively. The results indicated that the final products exhibited interesting magnetic, optical and targeting properties for further potential applications in biological and biomedical fields.