Preparation of Superparamagnetic Dextran-coated Iron Oxide Nanoparticles used as a Novel Gene Carrier into Human Bladder Cancer Cells'

Objective: Application of magnetic nanoparticles as gene carrier in gene therapy has developed quickly. This study was designed to investigate the preparation of superparamagnetic dextran-coated iron oxide nanoparticles (SDION) and the feasibility of SDION used as a novel gene carrier for plasmid DNA in vitro. Methods: SDION were prepared by chemical coprecipitation and separated by gel filtration on Sephacryl S-300HR, characterized by TEM, laser scattering system and Vibrating Sample Magnetometer Signal Processor. The green fluorescent protein (pGFP-C2) plasmid DNA was used as target gene. SDION-pGFP-C2 conjugate compounds were produced by means of oxidoreduction reaction. The connection ratio of SDION and pGFP-C2 DNA was analyzed and evaluated by agarose electrophoresis and the concentration of pGFP-C2 in supernatant was measured. Using liposome as control, the transfection efficiency of SDION and liposome was respectively evaluated under fluorescence microscope in vitro. Results: The diameter of SDION ranges from 3 nm to 8 nm, the effective diameter was 59.2 nm and the saturation magnetization was 0.23 emu/g. After SDION were reasonably oxidized, SDION could connect with pGFP-C2 to a high degree. The transfection efficiency of SDION as gene carrier was higher than that of liposome. Conclusion: The successes in connecting SDION with pGFP-C2 plasmid by means of oxidoreduction reaction and in transferring pGFP-C2 gene into human bladder cancer BIU-87 cells in vitro provided the experimental evidence for the feasibility of SDION used as a novel gene carrier.

Highly Efficient Labeling of Human Lung Cancer Cells Using Cationic Poly-L-lysine-Assisted Magnetic Iron Oxide Nanoparticles

Cell labeling with magnetic iron oxide nanoparticles(IONPs)is increasingly a routine approach in the cellbased cancer treatment.However,cell labeling with magnetic IONPs and their leading effects on the biological properties of human lung carcinoma cells remain scarcely reported.Therefore,in the present study the magnetic c-Fe2O3nanoparticles(MNPs)were firstly synthesized and surface-modified with cationic poly-L-lysine(PLL)to construct the PLL-MNPs,which were then used to magnetically label human A549 lung cancer cells.Cell viability and proliferation were evaluated with propidium iodide/fluorescein diacetate double staining and standard 3-(4,5-dimethylthiazol-2-diphenyl-tetrazolium)bromide assay,and the cytoskeleton was immunocytochemically stained.The cell cycle of the PLL-MNPlabeled A549 lung cancer cells was analyzed using flow cytometry.Apoptotic cells were fluorescently analyzed with nuclear-specific staining after the PLL-MNP labeling.The results showed that the constructed PLL-MNPs efficiently magnetically labeled A549 lung cancer cells and that,at low concentrations,labeling did not affect cellular viability,proliferation capability,cell cycle,and apoptosis.Furthermore,the cytoskeleton in the treated cells was detected intact in comparison with the untreated counterparts.However,the results also showed that at high concentration(400 lg m L-1),the PLL-MNPs would slightly impair cell viability,proliferation,cell cycle,and apoptosis and disrupt the cytoskeleton in the treated A549 lung cancer cells.Therefore,the present results indicated that the PLL-MNPs at adequate concentrations can be efficiently used for labeling A549 lung cancer cells and could be considered as a feasible approach for magnetic targeted anti-cancer drug/gene delivery,targeted diagnosis,and therapy in lung cancer treatment.

Use of PEI-coated Magnetic Iron Oxide Nanoparticles as Gene Vectors

Summary: To evaluate the feasibility of using polyethyleneimine (PEI) coated magnetic iron oxide nanoparticles (polyMAG-1000) as gene vectors. The surface characteristics of the nanoparticles were observed with scanning electron microscopy. The ability of the nanoparticles to combine with and protect DNA was investigated at different PH values after polyMAG-1000 and DNA were combined in different ratios. The nanoparticles were tested as gene vectors with in vitro transfection models. Under the scanning electron microscope the nanoparticles were about 100 nm in diameter. The nanoparticles could bind and condense DNA under acid, neutral and alkaline conditions, and they could transfer genes into cells and express green fluorescent proteins (GFP). The transfection efficiency was highest (51 %) when the ratio of nanoparticles to DNA was 1:1 (v:w). In that ratio, the difference in transfection efficiency was marked depending on whether a magnetic field was present or not: about 10 % when it was absent but 51 % when it was present. The magnetic iron oxide nanoparticles coated with PEI may potentially be used as gene vectors.

Magnetic iron oxide nanoparticles carrying PTEN gene to reverse cisplatin-resistance of A549/CDDP cell lines

To evaluate the feasibility of using magnetic iron oxide nanoparticle as wild PTEN gene carrier for transfection in vitro to reverse cisplatin-resistance of A549/CDDP cells, A549/CDDP cells were transfected with the wild PTEN gene expression plasmid (pGFP-PTEN) by magnetic iron nanoparticle and lipo2000. The transfection efficiency was detected by fluorescence microscope and flow cytometer. The expression levels of PTEN mRNA and protein were detected by reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemistry analysis. The effect of PTEN transfection on cell cycle enhances the sensitivity of A549/CDDP to cisplatin and nanoparticle-mediated transfection has a higher efficiency than that of the liposome-mediated group. The apoptosis level was up-regulated in PTEN transfection group. The magnetic iron oxide nanoparticle could be used as one of the ideal gene carriers for PTEN gene delivery in vitro. PTEN can be an effective target for reversing cisplatin-resistance in lung cancer.

Electrocatalytic oxidation of hydrazine on magnetic bar carbon paste electrode modified with benzothiazole and iron oxide nanoparticles: Simultaneous determination of hydrazine and phenol

A magnetic bar carbon paste electrode （MBCPE） modified with Fe3O4 magnetic nanoparticles （Fe3O4NPs） and 2‐（3,4‐dihydroxyphenyl） benzothiazole （DPB） for the electrochemical determina‐tion of hydrazine was developed. The DPB was firstly self‐assembled on the Fe3O4NPs, and the re‐sulting Fe3O4NPs/DPB composite was then absorbed on the designed MBCPE. The MBCPE was used to attract the magnetic nanoparticles to the electrode surface. Owing to its high conductivity and large effective surface area, the novel electrode had a very large current response for the electrocat‐alytic oxidation of hydrazine. The modified electrode was characterized by voltammetry, scanning electron microscopy, electrochemical impedance spectroscopy, infrared spectroscopy, and UV‐visible spectroscopy. Voltammetric methods were used to study the electrochemical behaviour of hydrazine on MBCPE/Fe3O4NPs/DPB in phosphate buffer solution （pH = 7.0）. The MBCPE/Fe3O4NPs/DPB, acting as an electrochemical sensor, exhibited very high electrocatalytic activity for the oxidation of hydrazine. The presence of DPB was found to reduce the oxidation potential of hydrazine and increase the catalytic current. The dependence of the electrocatalytic current on the hydrazine concentration exhibited two linear ranges, 0.1–0.4 μmol/L and 0.7–12.0 μmol/L, with a detection limit of 18.0 nmol/L. Additionally, the simultaneous determination of hydrazine and phe‐nol was investigated using the MBCPE/Fe3O4NPs/DPB electrode. Voltammetric experiments showed a linear range of 100–470 μmol/L and a detection limit of 24.3 μmol/L for phenol, and the proposed electrode was applied to the determination of hydrazine and phenol in water samples.

Bovine Serum Albumin-Conjugated Ferrimagnetic Iron Oxide Nanoparticles to Enhance the Biocompatibility and Magnetic Hyperthermia Performance

Magnetic hyperthermia is a fast emerging, non-invasive cancer treatment method which is used synergistically with the existing cancer therapeutics. We have attempted to address the current challenges in clinical magnetic hyperthermia-improved biocompatibility and enhanced heating characteristics, through a single combinatorial approach. Both superparamagnetic iron oxide nanoparticles(SPIONs) of size 10 nm and ferrimagnetic iron oxide nanoparticles(FIONs) of size 30 nm were synthesized by thermal decomposition method for comparison studies. Two different surface modifying agents, viz, Cetyl Trimethyl Ammonium Bromide and 3-Aminopropyltrimethoxysilane, were used to conjugate Bovine Serum Albumin(BSA) over the iron oxide nanoparticles via two different methods—surface charge adsorption and covalent amide bonding, respectively. The preliminary haemolysis and cell viability experiments show that BSA conjugation mitigates the haemolytic effect of the iron oxide nanoparticles on erythrocytes and is non-cytotoxic to the healthy Baby Hamster Kidney cells. It was observed from the results that due to better colloidal stability, the SAR value of the BSA-iron oxide nanoparticles is higher than the iron oxide nanoparticles without BSA, irrespective of the size of the iron oxide nanoparticles and method of conjugation. The BSA-FIONs seem to show improved biocompatibility, as the haemolytic index is less than 2 % and cell viability is up to 120 %, when normalized with the control. The SAR value of BSAFIONs is 2300 Wg^(-1) when compared to 1700 Wg^(-1) of FIONs without BSA conjugation. Thus, we report here that BSA conjugation over FIONs(with a high saturation magnetization of 87 emug^(-1)) provide a single combinatorial approach to improve the biocompatibility and enhance the SAR value for magnetic hyperthermia, thus addressing both the current challenges of the same.

Influence of magnetic iron oxide nanoparticles on red blood cells and Caco-2 cells

The interactions of two types of cells (red blood cells, Caco-2 cells) with magnetic iron oxide nanoparticles (non-grafted, citrate-grafted, dendrimer-grafted) of 11 nm in size have been investigated. We focused on two important physiological parameters of the cells, the intracellular pH and the intracellular Ca2+ content. The results show that the nanoparticles do not have a significant influence on the pH and Ca2+ content of Caco-2 cells. The Ca2+ content of red blood cells is also not affected but the intracellular pH is slightly reduced.

Doping engineering of iron oxide nanoparticles towards high performance and biocompatible T_(1)-weighted MRI contrast agents

Extremely small-sized iron oxide nanoparticles(IONPs) are of great interest in magnetic resonance imaging(MRI) due to their biosafety as an alternative to clinical gadolinium(Ⅲ) complexes-based contrast agents.Especially when the particle size is less than 10 nm,it has strong diffusion ability and deep penetration distance in tumor tissue.Substitution doping can significantly enhance the T_(1)contrast effect of nanoparticles by regulating the surface exposed atoms.However,the nucleation and growth processes of multi-component synthesis systems are complex and difficult to be accurately controlled,leading to great challenges in the synthesis of ultra-small-sized nanoparticles with different components and sizes.Here,extremely smallsized superparamagnetic gadolinium-doped iron oxide nanoparticles(GdIONPs,Gd_(x)Fe_(3-x)O_(4) NPs) with adjustable doping amount and controllable size in the range of 3.5-7.5 nm were synthesized by thermal decomposition.Then,as-synthesized GdIONPs were surface modified with a highly water-soluble and biocompatible carboxyl-polyethylene glycol-phosphoric acid ligand with high binding affinity.Gd_(0.65)Fe_(2.35)O_(4) NPs exhibited very high r_(1) relaxivity of 10.6 mmol^(-1)·L·s^(-1) in terms of all metal concentrations and 49.0 mmol^(-1)·L·s^(-1) in terms of gadolinium alone,respectively,3 and 14 times higher than clinical T_(1) contrast agents(Gd-DTPA).GdIONPs can continuously obtain high resolution images of blood vessels,and can be used as an efficient and multifunctional contrast agent for MR T_(1)imaging.This stable and efficient doping strategy provides an easy and effective method to individually optimize the magnetic properties of complex oxides and their relaxation effects for a variety of biomedical applications.

In Vitro Targeted Magnetic Delivery and Tracking of Superparamagnetic Iron Oxide Particles Labeled Stem Cells for Articular Cartilage Defect Repair

To assess a novel cell manipulation technique of tissue engineering with respect to its ability to augment superparamagnetic iron oxide particles （SPIO） labeled mesenchymal stem cells （MSCs） density at a localized cartilage defect site in an in vitro phantom by applying magnetic force. Meanwhile, non-invasive imaging techniques were use to track SPIO-labeled MSCs by magnetic resonance imaging （MRI）. Human bone marrow MSCs were cultured and labeled with SPIO. Fresh degenerated human osteochondral fragments were obtained during total knee arthroplasty and a cartilage defect was created at the center. Then, the osteochondral fragments were attached to the sidewalls of culture flasks filled with phosphate-buffered saline （PBS） to mimic the human joint cavity. The SPIO-labeled MSCs were injected into the culture flasks in the presence of a 0.57 Tesla （T） magnetic force. Before and 90 min after cell targeting, the specimens underwent T2-weighted turbo spin-echo （SET2WI） sequence of 3.0 T MRI. MRI results were compared with histological findings. Macroscopic observation showed that SPIO-labeled MSCs were steered to the target region of cartilage defect. MRI revealed significant changes in signal intensity （P0.01）. HE staining exibited that a great number of MSCs formed a three-dimensional （3D） cell ＂sheet＂ structure at the chondral defect site. It was concluded that 0.57 T magnetic force permits spatial delivery of magnetically labeled MSCs to the target region in vitro. High-field MRI can serve as an very sensitive non-invasive technique for the visualization of SPIO-labeled MSCs.

Recovering limonite from Australia iron ores by flocculation-high intensity magnetic separation

Successful recovery of limonite from iron fines was achieved by using flocculation-high intensity magnetic separation （FIMS） and adding hydrolyzed and causticized flocculants according to the characteristic of iron fines. The separation results of the three iron samples are as follows： iron grade 66.77%- 67.98% and the recovery of iron 69.26%-70.70% by the FIMS process with flocculants. The comparative results show that under the same separation conditions the F1MS process can effectively increase the recovery of iron by 10. 97%- 15.73%. The flowsheet results confirm the reliability of the process in a SHP high intensity magnetic separator. The concentrate product can he used as raw materials for direct reduction iron-smelting. The hydrolyzed and causticized flocculants can selectively flocculate fine feebly-magnetic iron mineral particles to increase their apparent separation sizes. The larger the separation size, the stronger the magnetic force. By comparing the separation results of the three samples it is found that among the three samples the higher the limonite content, the better the separation result. This means that the separation result relates closely to the flocculation process and the adding pattern of the flocculant.

Fe_3O_4@PAM@NTA-Ni^(2+) Magnetic Composite Nanoparticles for Highly Specific Separation of His-tagged Proteins

A facile approach has been developed to synthesize Fe3O4@PAM（polyacrylamide） nanoparticles（NPs） with carboxyl groups on the surfaces by copolymerization with acrylamide and acrylic acid in Fe3O4 NPs aqueous suspension. Nitrilotriacetic acid（NTA） was conjugated to the magnetic NPs via well-known carboniimide chemistry using EDC and NHS. The Ni^（2＋） ions loaded on the surface of NPs provide abundant docking sites for immobilization of His-tagged green fluorescent proteins（His-tagged GFP）. The high magnetic property of Fe3O4@PAM@NTA-Ni^（2＋） allows an easy separation of the NPs from solution under an external magnetic field, with high His-tagged protein binding capacity（42 μg protein/mg of NPs）. The NPs can be recycled for at least four times without significant loss of binding capacity to proteins. These materials show great potential to separate His-tagged protein with low-cost purification at industrial scale.

M2 macrophage-targeted iron oxide nanoparticles for magnetic resonance image-guided magnetic hyperthermia therapy

Tumor-associated macrophages(TAMs)play an important role in tumor development and progression.In particular,M2 TAMs can promote tumor growth by facilitating tumor progression and malignant behaviors.Selectively targeted elimination of M2 TAMs to inhibit tumor progression is of great significance for cancer treatment.Iron oxide nanoparticles based magnetic hyperthermia therapy(MHT)is a classical approach to destroy tumor tissue with deep penetration depth.In this study,we developed a typical M2 macrophage-targeted peptide(M2pep)functionalized superparamagnetic iron oxide nanoparticle(SPIO)for magnetic resonance imaging(MRI)-guided MHT in an orthotopic breast cancer mouse model.The obtained multifunctional SPIO-M2pep with a hydrodynamic diameter of 20 nm showed efficient targeting capability,high transverse relaxivity(149 mM^(-1) s^(-1))and satisfactory magnetic hyperthermia performance in vitro.In vivo studies demonstrated that the SPIO-M2pep based MRI can monitor the distribution of nanoparticles in tumor and indicate the suitable timing for MHT.The M2 macrophage-targeted MHT significantly reduced the tumor volume and the population of pro-tumoral M2 TAMs in tumor.In addition,the SPIO-M2pep based MHT can remodel the tumor immune microenvironment(TIME).The multifunctional SPIO-M2pep with M2 macrophage-targeting ability,high magnetic hyperthermia efficiency,MR imaging capability and effective role in remodeling the TIME hold great potential to improve clinical cancer therapy outcomes.

Comparative Study of Images with Pathology:Superparamagnetic Iron Oxide-enhanced Magnetic Resonance Image(MRI)of Splenic VX2 Tumor in Rats

Objective： To establish a rodent model of VX2 tumor of the spleen, to analyze relationship between the change of the signal intensity on superparamagnetic iron oxide enhanced magnetic resonance image （MRI） and pathologic change to evaluate the ability of superparamagnetic iron oxide enhanced MRI for detection of splenic metastases. Methods： 8 rodent models of VX2 tumor of spleen were established successfully. The images were obtained before and after administration of superparamagnetic iron oxide. T1-weighted spin-echo （SE） pulse sequence with a repetition time （TR） of 450 msec, and echo time （TE） of 12 msec （TR/TE=450/12） was used. The imaging parameters of T2-weighted SE pulse sequence were as follows： TR/TE=4000/128. Results： On plain MR scanning T1-weighted splenic VX2 tumor showed hypointensity or isointensity which approximated to the SI of splenic parenchyma. Therefore all lesions were not displayed clearly. On superparamagnetic iron oxide enhancement T2WI sequence the SI of splenic parenchyma decreased obviously with percentage of signal intensity loss （PSIL） of 55.04%, But the SI of tumor was not evidently changed with PSIL of 0.87%. Nevertheless the SNR of normal splenic parenchyma around the lesions had obvious difference （P〈0.001） comparatively. Therefore the contrast between tumor and spleen increased, and tumor displayed more clearly. Moreover the contrast-to-noise （CNR） between VX2 tumor and splenic parenchyma had an evident difference before and after admininstration of superparamagnetic iron oxide （P〈0.001）. Conclusion： On superparamagnetic iron oxide enhancement T1WI sequence the contrast of tumor-to-spleen is poor. Therefore it is not sensitive to characterize the lesions in spleen. On superparamagnetic iron oxide enhanced T2WI the contrast degree of lesions increases obviously. Consequently, superparamagnetic iron oxide -enhanced T2WI MRI scanning can improve the rate of detection and characterization for lesions of spleen.

Efficient degradation of dye pollutants in wastewater via photocatalysis using a magnetic zinc oxide/graphene/iron oxide-based catalyst

In this paper, we present a proof-of-concept study of the enhancement of photocatalytic activity via a combined strategy of fabricating a visible-light responsive ternary heterostructure and improving overall photostability by incorporating magnetic zinc oxide/graphene/iron oxide (ZGF). A solvothermal approach was used to synthesize the catalyst. X-ray diffraction (XRD), scanning electron microscopic, energy dispersive X-ray, transmission electron microscopic, vibrating sample magnetometric, and ultraviolet–visible diffuse reflectance spectroscopic techniques were used to characterize the synthesized samples. The obtained optimal Zn(NO_(3))_(2) concentration, temperature, and heating duration were 0.10 mol/L, 600℃, and 1 h, respectively. The XRD pattern revealed the presence of peaks corresponding to zinc oxide, graphene, and iron oxide, indicating that the ZGF catalyst was effectively synthesized. Furthermore, when the developed ZGF was used for methylene blue dye degradation, the optimum irradiation time, dye concentration, catalyst dosage, irradiation intensity, and solution pH were 90 min, 10 mg/L, 0.03 g/L, 100 W, and 8.0, respectively. Therefore, the synthesized ZGF system could be used as a catalyst to degrade dyes in wastewater samples. This hybrid nanocomposite consisting of zinc oxide, graphene, and iron oxide could also be used as an effective photocatalytic degrader for various dye pollutants.

Growth and differentiation of neural stem cells with superparamagnetic iron oxides labeling in vitro

Objective： To study the growth and differentiation of superparamagnetie iron oxides（SPIOs） labeled neural stem cells （NSCs）. Methods： After NSCs were cultured and subcuhured from newborn rat brain, they were magnetically labeled with ferumoxides （a kind of SPIOs ）. Growth, differentiation and other biology properties of the cells were investigated with immunocytochemistry, transmission electron microscopy （TEM） and Prussian blue staining. Results： Nestin positive cells were found in the culture and offspring clones. NSCs could be differentiated into positive GFAP and NF200 cells in serum culture. When NSCs incubated with ferumoxides, the iron particles were seen in intracellular as well as in offspring clones. With the increase in concentration of ferumoxides （5.6-11.2/μg/ml）, ferumoxides showed no significant difference effects on the growth and differentiation of NSCs. When the concentration of ferumoxides exceeded 22.4μg/ml ,there was significant difference（P〈0.05）. Conclusion： We successfully label NSCs with ferumoxides,it is useful for tracking of magnetic labeled NSCs in vivo with MRI.

Spy chemistry enables stable protein immobilization on iron oxide nanoparticles with enhanced magnetic properties

Iron oxide nanoparticles(IONPs)modified with functional proteins hold great promise in the biomedical field.However,conventional protein modification strategies,such as adsorption and covalent coupling,are either unstable or nonspecific,or may result in the changes of protein structure and ultimately the loss of protein activity.Modification of active proteins on small-sized IONPs with a particle size of less than 30 nm is especially difficult due to their high surface energy.Herein,we developed a universal modifica-tion method based on Spy chemistry for rapid and stable protein immobilization on small-sized IONPs,which only requires the presence of active groups on the surface of nanoparticles that can couple with SpyCatcher.In short,the SpyCatcher peptides were first coated on the surface of IONPs by cross-linking with activated groups,and then the SpyTag peptide fused with a model protein(enhanced green fluo-rescent protein,EGFP)was engineered(SpyTag-EGFP)and directly coupled to SpyCatcher-modified IONPs by self-assembly,which is spontaneous and robust while avoiding the effect of chemical reactions on functional protein activity.The obtained EGFP-functionalized IONPs exhibited enhanced and stable green fluorescence and improved magnetic properties.In addition,the cell internalization efficiency of EGFP-functionalized IONPs was significantly increased as compared to unmodified IONPs,providing an ideal solution for efficient cell labeling and tracking.In conclusion,here we report a rapid and easy strategy for EGFP immobilization on IONPs based on Spy chemistry,which could be further adapted to other functional proteins in the future.SpyCatcher-modified IONPs and SpyTag-X(arbitrary functional fusion proteins)hold great potential to be applied as a versatile platform for protein immobilization on IONPs and enable its multifunctional application in the future.

MRI tracking of human Wharton’s jelly stem cells seeded onto acellular dermal matrix labeled with superparamagnetic iron oxide nanoparticles in burn wounds

Background:In vivo cell tracking after transplantation in regenerative medicine remains an unmet challenge and limits current understanding of the wound healing mechanism through cell-based therapies.This study investigated tracking of human Wharton’s jelly stem cells(hWJSCs)seeded onto an acellular dermal matrix(ADM)and labeled with superparamagnetic iron oxide nanoparti-cles(SPIONs)by magnetic resonance imaging(MRI)in burn injury.Method:The hWJSCs were characterized and assessed for growth kinetics.A total of 30 rats were enrolled in three equal groups.Group 1 underwent scald burn injury left without treatment,the group 2 was treated by an ADM that was prepared from cosmetic surgery skin samples and the group 3 received hWJSCs labeled with SPIONs seeded onto an ADM.Tensile strength was evaluated before and after interventions,real time PCR assessed apoptosis,and Prussian blue staining,scanning electron microscopy(SEM)and MRI were used for the tracking of labeled cells.Results:The hWJSCs exhibited mesenchymal stem cell properties.Population doubling time was 40.1 hours.SPIONs did not show any toxic effect.The hWJSCs seeded onto an ADM decreased Bax and increased Bcl-2 gene expression.Internalization of SPIONs within hWJSCs was confirmed by Prussian blue staining,SEM and MRI until day 21.There was a significant difference between the Young’s moduli of normal skin and the group receiving hWJSCs seeded onto an ADM.Histological observations and SEM imaging confirmed that MRI is an accurate method to track SPION-labeled hWJSCs in vivo.Conclusions:This study showed that SPION labeling coupled with MRI can be used to further understand the fate of stem cells after transplantation in a burn model.

Recovery of iron from high phosphorus oolitic iron ore using coal-based reduction followed by magnetic separation

Oolitic iron ore is one of the most important iron resources. This paper reports the recovery of iron from high phosphorus oolitic iron ore using coal-based reduction and magnetic separation. The influences of reduction temperature, reduction time, C/O mole ratio, and CaO content on the metallization degree and iron recovery were investigated in detail. Experimental results show that reduced products with the metallization degree of 95.82% could be produced under the optimal conditions （i.e., reduction temperature, 1250℃; reduction time, 50 min; C/O mole ratio, 2.0; and CaO content, 10wt%）. The magnetic concentrate containing 89.63wt% Fe with the iron recovery of 96.21% was obtained. According to the mineralogical and morphologic analysis, the iron minerals had been reduced and iron was mainly enriched into the metallic iron phase embedded in the slag matrix in the form of spherical particles. Apatite was also reduced to phosphorus, which partially migrated into the metallic iron phase.

Carbothermic reduction characteristics of ludwigite and boron–iron magnetic separation

Ludwigite is a kind of complex iron ore containing boron, iron, and magnesium, and it is the most promising boron resource in China. Selective reduction of iron oxide is the key step for the comprehensive utilization of ludwigite. In the present work, the reduction mechanism of ludwigite was investigated. The thermogravimetry and differential scanning calorimetry analysis and isothermal reduction of ludwigite/coal composite pellet were performed. Ludwigite yielded a lower reduction starting temperature and a higher final reduction degree compared with the traditional iron concentrates. Higher specific surface area and more fine cracks might be the main reasons for the better reducibility of ludwigite. Reducing temperature highly affected the reaction fraction and microstructure of the reduced pellets, which are closely related to the separation degree of boron and iron. Increasing reducing temperature benefited the boron and iron magnetic separation. Optimum magnetic separation results could be obtained when the pellet was reduced at 1300°C. The separated boron-rich non-magnetic concentrate presented poor crystalline structure, and its extraction efficiency for boron reached 64.3%. The obtained experimental results can provide reference for the determination of the comprehensive utilization flow sheet of ludwigite.

Current status of superparamagnetic iron oxide contrast agents for liver magnetic resonance imaging

Five types of superparamagnetic iron oxide （SPIO）,i.e. Ferumoxides （Feridex？ Ⅳ, Berlex Laboratories）,Fe r u c a r b o t ra n （ Re s ov i s t？, B aye r H e a l t h c a re ） ,Ferumoxtran-10 （AMI-227 or Code-7227, Combidex？, AMAG Pharma; Sinerem？, Guerbet）, NC100150（Clariscan？, Nycomed,） and （VSOP C184, Ferropharm）have been designed and clinically tested as magneticresonance contrast agents. However, until nowResovist？ is current available in only a few countries.The other four agents have been stopped for furtherdevelopment or withdrawn from the market. AnotherSPIO agent Ferumoxytol （Feraheme） is approved forthe treatment of iron deficiency in adult chronic kidneydisease patients. Ferumoxytol is comprised of ironoxide particles surrounded by a carbohydrate coat, andit is being explored as a potential imaging approach forevaluating lymph nodes and certain liver tumors.