Electrospun NiFe2O4 nanofibers as high capacity anode materials for Li-ion batteries.

Ultra-long NiFe2O4 nanofibers were synthesized by a simple electrospinning process followed by thermal treatment. The NiFe2O4 nanofibers are polycrystalline with average diameter of 218 nm and lengths up to several millimeters. When evaluated for their lithium-storage properties, the electrospun NiFe2O4 nanofibers exhibit a high specific capacity that can exceed 660 mA h g(-1) after 100 cycles, along with enhanced cycling stability.

Induced heat property of polyethyleneglycol-coated iron oxide nanoparticles with dispersion stability for hyperthermia.

Fe3O4 nanoparticles have been used for hyperthermia treatment in an attempt to overcome various problems. When using hyperthermia treamtment, it is critical to control the surface modification of the particles. Magnetic nanoparticles tend to aggregate due to strong magnetic dipole--dipole attractions. The particles then have a high surface area and are of larger sizes, posing serious practical limitations. The nanoparticles are used to generate maximum heat and to maintain a constant heating temperature using the minimum magnetic nanoparticles dosage. In this study, we investigated the effect of PEG coated onto Fe3O4 nanoparticles. We tested the dispersion stability and repetitive heating property of nanoparticles for different PEG concentrations under an AC magnetic field. The results confirmed that the nanoparticles on a colloidal system maintained the heating properties of repetitve inductive heating as PEG concentration increased with dispersion stability. The nanoparticles with superior dispersion stability will be appropriate for hyperthermia applications in cancer treatments.

Characterization and stability of liposome-enveloped trypsin/Fe3O4 for drug delivery and drug release behavior.

Liposome encapsulating Fe3O4 (liposome complexes) has been prepared for targeting a drug to a specific organ, as well as for MRI (magnetic resonance imaging) contrast agents. The objective of the present work was to investigate the Fe3O4 properties and the effects of chitosan concentration on the characteristics of chitosan-coated liposome complexes. They were characterized by DLS, FT-IR, XRD, VSM, UV-Vis spectrometer, TEM and phase-contrast microscopy. The average liposome complex size was approximately 500 nm, with individual Fe3O4 nanoparticle sizes of 10 nm. The drug incorporation efficiency of trypsin in liposome complexes was 65-69%, the drug release was sustained and the incorporated drugs had the magnetization properties of the liposome complexes. Incorporation of chitosan into the liposome bilayer decreased trypsin release from the liposome complexes due to an increased rigidity of the liposome membrane structure. Chitosan-coated liposome complexes showed a higher stability when compared with the stability of non-coated liposome complexes.

Preparation, characterization, cytotoxicity and drug release behavior of liposome-enveloped paclitaxel/Fe3O4 nanoparticles.

Phospholipid vesicles encapsulating magnetic nanoparticles (liposome complexes) have been prepared for targeting a drug to a specific organ using a magnetic force, as well as for local hyperthermia therapy. Liposome complexes are also an ideal platform for use as contrast agents of magnetic resonance imaging (MRI). We describe the preparation and characterization of liposomes containing magnetite. These liposomes were obtained by thin film hydration method and Fe3O4 nanoparticles were synthesized by coprecipitation method. They were characterized by an electrophoretic light scattering spectrophotometer, the liposome complexes were subsequently coated using chitosan. We have further investigated the ability of the above formulation for drug delivery and MRI applications. We are specifically interested in evaluating our liposome complexes for drug therapy; hence, we selected paclitaxel for the combination study. The amount of paclitaxel was measured at 227 nm using a UV-Vis spectrophotometer. Cytotoxicity of liposome complexes was treated with the various concentrations of paclitaxel in PC3 cell lines. The structure and properties of liposome complexes were analyzed by FT-IR, XRD and VSM. The particle size was analyzed by TEM and DLS.

Preparation and characterization of TiO2 coated Fe nanofibers for electromagnetic wave absorber.

Recently, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) have become serious problems due to the growth of electronic device and next generation telecommunication. It is necessary to develop new electromagnetic wave absorbing material to overcome the limitation of electromagnetic wave shielding materials. The EMI attenuation is normally related to magnetic loss and dielectric loss. Therefore, magnetic material coating dielectric materials are required in this reason. In this study, TiO2 coated Fe nanofibers were prepared to improve their properties for electromagnetic wave absorption. Poly(vinylpyrrolidone) (PVP) and Iron (III) nitrate nonahydrate (Fe(NO3)3 x 9H2O) were used as starting materials for the synthesis of Fe oxide nanofibers. Fe oxide nanofibers were prepared by electrospinning in an electric field and heat treatment. TiO2 layer was coated on the surface of Fe oxide nanofibers using sol-gel process. After the reduction of TiO2 coated Fe oxide nanofibers, Fe nanofibers with a TiO2 coating layer of about 10 nm were successfully obtained. The morphology and structure of fibers were characterized by SEM, TEM, and XRD. In addition, the absorption properties of TiO2 coated Fe nanofibers were measured by network analyzer.

Synthesis, Morphology Control and Electromagnetic Wave Absorption Properties of Electrospun FeCo Alloy Nanofibers.

Recently, increasing interest has been focused on one-dimensional (1 D) magnetic nanomaterials that have significant anisotropic electromagnetic parameters and size effects that can be used to achieve improved shielding efficiency. In this study, the simple, low-cost and scalable synthesis of FeCo nanofibers is demonstrated by combining an electrospinning process with sequential thermal treatment involving calcination in air followed by reduction in H2 atmosphere. A citric acid has an influence on the morphology of the electrospun product. The as-spun precursor nanofibers are transformed into CoFe2O4 and FeCo phases through the sequential thermal treatment while maintaining the fibrous shapes. To evaluate the electromagnetic (EM) wave-absorbing abilities of the FeCo nanofibers, epoxy matrix composites with the nanofibers are fabricated. The composites show excellent EM wave absorption properties where the power loss of the FeCo nanofibers increased to 20 GHz without any degradation.

Effect of calcination temperature on the photocatalytic properties of electrospun TiO2 nanofibers.

In this study, TiO2 nanofibers with a high aspect ratio and a large specific surface area were synthesized using the electrospinning technique, and the effect of calcination temperature on their crystal structure, diameter, specific surface area and photocatalytic activity was systematically investigated. The electrospun, as-prepared PVP/TTIP nanofibers were several tens of micrometers in length with a diameter of 74 nm. TiO2 nanofibers with an average diameter of 50 nm were prepared after calcination at various temperatures. The calcination temperature significantly influenced the photocatalytic and material properties of TiO2 including grain size and specific surface area. When compared to other nanostructured TiO2 materials, such as commercial TiO2 nanoparticles (P25, Degussa), the TiO2 nanofibers exhibited greater photocatalytic activity for the degradation of acetaldehyde and ammonia.