磁性纳米四氧化三铁在生物医学中的应用

近年来,由于磁性纳米粒子在实际应用中发挥越来越重要的作用,有关磁性纳米粒子的应用受到科学界广泛关注,特别是生物医学领域。由于磁性纳米Fe_3O_4粒子制作简单且晶体对细胞无毒,在生物医药领域大量应用,磁性纳米Fe_3O_4粒子主要通过表面包覆成为免疫磁性微球进行使用。简述了磁性纳米Fe_3O_4粒子的制备方法,重点综述了近些年磁性纳米Fe_3O_4粒子在生物医学上的应用,包括磁共振成像技术、磁分离技术、靶向药物载体技术、肿瘤热疗技术、造影剂技术,并且阐述了磁性纳米Fe_3O_4粒子的发展前景。     

储存时间对SMP/Fe3O4形状回复性能的影响

首先制备了形状记忆性良好、在热场和磁场中都可响应的SMP/Fe3O4纳米复合材料,将样品在形变固定后,储存不同时间,分别在热场和磁场中考察储存时间对SMP/Fe3O4回复性能的影响。结果显示,储存时间10min及储存时间为12h的样品的形状回复率均在95%以上,存储时间对于热场和磁场中形变回复性能的影响具有类似的规律,即:形变固定后储存时间延长,其起始回复温度升高,回复诱导期增长,回复的温度区间变宽。XRD、DSC、DMA测试结果表明,随储存时间的延长,样品的结晶度增加,样品熔点和熔融温度区间发生改变,从而引起相应的SMP/Fe3O4回复性能的变化。     

Au/Fe3O4磁性纳米粒子的合成及表征

报道了一种合成具有巯基官能团修饰的Au/Fe_3O_4磁性纳米粒子的新方法。采用共沉淀法制备Fe_3O_4磁性纳米颗粒,并在此基础上用聚(烯丙胺)溶液还原HAuCl4,制得Au/Fe_3O_4磁性核壳纳米颗粒,再用3-巯基-1-丙磺酸钠修饰Au/Fe_3O_4磁性纳米粒子,最后得到具有巯基官能团稳定的Au/Fe_3O_4磁性纳米粒子。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)、振动样品磁强计(VSM)分别对产物的微观结构及磁性特征进行表征。     

Preparation and characterisation of PPy/NanoGs/Fe3O4 conductive and magnetic nanocomposites

Nanocomposites composed of polypyrrole (PPy), graphite nanosheets (NanoGs), magnetite (Fe₃O₄) nanoparticles, have been successfully synthesised with a two-step process. First, we prepared NanoGs/Fe₃O₄ powder via wet chemical co-precipitation method. Next, pyrrole was polymerised in the suspension of NanoGs/Fe₃O₄ and then PPy/NanoGs/Fe₃O₄ nanocomposites were produced. The products were characterised by Fourier-transform infrared spectroscopy, Transmission electron microscopy, Thermogravimetric, conductivity and magnetisation analysis. The result showed that the conductivity of the PPy/NanoGs/Fe₃O₄ composites, compared with pure PPy, increased dramatically. And the saturation magnetisation of nanocomposites increased with the increase of the volume fraction of the Fe₃O₄ particles. In addition, according to the thermal gravimetric analysis, compared with PPy, nanocomposites exhibited enhanced thermal stability due to the introduction of NanoGs/Fe₃O_4. The PPy/NanoGs/Fe₃O₄ composites show potential applications in electric–magnetic shield materials.     

Assembly of Fe3O4 nanoparticles on SiO2 monodisperse spheres

The assembly of superparamagnetic Fe₃O₄ nanoparticles on submicroscopic SiO₂ spheres have been prepared by an in situ reaction using different molar ratios of Fe³⁺/Fe²⁺ (50–200%). It has been observed that morphology of the assembly and properties of these hybrid materials composed of SiO₂ as core and Fe₃O₄ nanoparticles as shell depend on the molar ratio of Fe³⁺/Fe²⁺.     

Characteristic analysis of Fe3O4 nanoparticles modified by oleic acid and undecylenic acid

Carbonization of magnetic polymer microspheres is one of the methods for the preparation of magnetic carbon materials. Fe₃O₄ magnetic particle characteristics considerably influence the magnetic content and size distribution of magnetic polymer microspheres. The characteristics of Fe₃O₄ nanoparticles modified by oleic acid (OA) and undecylenic acid (UA) were analyzed by X-ray diffraction, Fourier transform infrared, scanning electron microscopy, dynamic laser light scattering, thermogravimetry/differential thermogravimetry, vibrating sample magnetometer, and water contact angle. Fe₃O₄ nanoparticles modified by OA and UA are nearly spherical and exhibit superparamagnetism. Fe₃O₄ particle size and saturation magnetization are slightly influenced by the OA and UA composition. OA and UA both are chemically adsorbed onto Fe₃O₄ as bidentate chelates. OA shows easier adsorption onto Fe₃O₄ than UA. OA groups have an expanded arrangement on OA@Fe₃O₄, whereas UA groups have a condensed arrangement on UA@Fe₃O₄. Particle lipophilicity decreases and particle clustering increases with decreasing OA content and increasing UA content on OA-UA@Fe₃O₄ nanoparticles.     

Electronic and Magnetic Properties of Superconducting Sr4V2Fe2As2O6 Versus Sr4Sc2Fe2As2O6

First principles of FLAPW-GGA calculations have been performed with the purpose to understand the peculiarities of band structure and Fermi surface topology for recently discovered 37 K superconductor: Sr₄V₂Fe₂As₂O₆—in comparison with isostructural phase Sr₄Sc₂Fe₂As₂O₆. Our main finding is that the replacement of Sc with V leads to drastic transformation of electronic, magnetic and conductive properties of these materials: as against non-magnetic Sr₄Sc₂Fe₂As₂O₆ which is formed from non-magnetic conducting [Fe₂As₂] and insulating [Sr₄Sc₂O₆] blocks, Sr₄V₂Fe₂As₂O₆ consists of non-magnetic conducting [Fe₂As₂] blocks and [Sr₄V₂O₆] blocks which exhibit magnetic half-metallic properties.     

Fe2O3掺杂MgTiO3-CaTiO3微波陶瓷的介电性能研究

采用固相法制备0.93MgTiO3-0.07CaTiO3-xFe_2O_3(摩尔分数x=0.01~0.025)微波介质陶瓷材料,研究添加Fe_2O_3后,体系的晶体结构、显微结构和微波介电性能之间的变化规律。利用XRD、SEM、网络分析仪对样品的相组成、微观结构、介电性能进行测试分析。研究表明:该复合陶瓷样品的致密度、介电常数和Q·f值随Fe_2O_3含量的增加先增大后减小。当x(Fe_2O_3)为0.015,在1290℃烧结4h时,获得最优的介电性能:εr=21.32,Q·f=37448GHz,τf=0.577×10-6/℃。     

Research on hydrophobicity of electrospun Fe3O4/PVDF nanofiber membranes under different preparation conditions

Abstract

Preparation condition can affect the structure and the properties of nanofiber membrane. In order to explore suitable conditions to prepare the Fe₃O₄/PVDF nanofiber membrane with good hydrophobicity, the hydrophobicity of Fe₃O₄/PVDF nanofiber membranes obtained by electrospinning was investigated by changing preparation conditions like weight percentage of Fe₃O₄ nanoparticles, blending quality concentration of poly (vinylidene fluoride) (PVDF) and Fe₃O₄ nanoparticles, and positive voltage. And the variations of hydrophobicity of Fe₃O₄/PVDF nanofiber membranes modified by 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane were studied. The results show that the hydrophobicity of Fe₃O₄/PVDF nanofiber membranes has changed under different preparation conditions. The contact angles of samples increased after a modification by 1H, 1H, 2H, 2H-perfluorodecyl trimethoxysilane, which indicates that the hydrophobicity of Fe₃O₄/PVDF nanofiber membranes has been enhanced.     

强磁性Ni掺杂Fe3O4纳米磁粉的研制

用化学共沉淀法制备了强磁性的Ni掺杂Fe3O4纳米磁粉。采用X射线衍射仪、电感耦合等离子发射光谱仪、傅立叶红外-拉曼光谱仪、透射电子显微镜、振动样品磁强计对掺杂Fe3O4纳米粒子进行了物相结构和磁性能表征。结果表明，掺杂Fe3O4磁粉的粒径在20nm左右，其比饱和磁化强度（σs）可达114emu／g，大大超过了一般Fe3O4纳米磁粉的比饱和磁化强度（σs），并进一步分析了掺杂Fe3O4纳米粒子的磁性能有较大提高的原因。     

Structural and optical properties of spray pyrolytically prepared Fe2O3 thin films

Fe₂O₃ thin film was prepared using aqueous solution of FeCl₃ by spray pyrolysis. The substrate temperature was 450°C. The lattice parametersa andc for different concentrations were calculated from X-ray diffraction study. Hexagonal structure of the Fe₂O₃ thin film was confirmed. Band gap values of Fe₂O₃ prepared from different concentrations were determined from optical transmission data.     

Fe3O4磁性纳米颗粒的合成与接枝聚合修饰（英文）

以氨水作为沉淀剂并控制溶液的pH值,采用Fe3+和Fe2+共沉淀法制得了磁性四氧化三铁纳米颗粒。合成的磁性纳米颗粒通过高分辨透射电镜、X射线衍射仪、傅里叶变换红外光谱仪进行了表征。四氧化三铁纳米颗粒的粒径约为10nm,其表面含有丰富的羟基。为了增强磁性四氧化三铁纳米颗粒和聚合物基质之间的相互作用,在纳米颗粒的表面接枝上乙烯基单体。傅里叶变换红外光谱仪和热重分析仪的测试结果显示,聚合物链共价结合在纳米颗粒表面。表面接枝聚合后,四氧化三铁纳米颗粒由极性转变为非极性。     

磁性Fe3O4纳米颗粒的可控制备及生长研究

采用热法合成磁性Fe3O4纳米颗粒,通过精细调控实验条件能对其形状和大小进行有效控制。采用X射线衍射仪、透射电镜、振动样品磁强计等对Fe3O4纳米颗粒的成分、形貌及磁性等进行了表征测试。结果表明,Fe3O4纳米颗粒的饱和磁化强度为62.5emu/g。最后探讨了Fe3O4纳米颗粒的合成机理。     

A Study of the Effect of Nanometer Fe3O4 Addition on the Properties of Silicone Oil-based Magnetorheological Fluids

With the aim to improve the performance of magnetorheological fluids (MRFs) for mechanical transmission system, a process to prepare silicone oil-based MRFs with the addition of nanometer Fe₃O₄ particles is presented and five MRFs samples with different mass fraction of nanometer Fe₃O₄ particles have been prepared. The experimental materials, the preparation process, and test methods are elaborated. Moreover, the microstructures of soft magnetic carbonyl iron particles, nanometer Fe₃O₄ particles, and carbonyl iron/nano-sized Fe₃O₄ composites have been characterized via scanning electron microscope (SEM). Finally, test experiments of sedimentation stability, zero field viscosity, and shear yield stress have been carried out. The experimental results show that adding a certain amount of nanometer Fe₃O₄ particles (4 and 6 wt%) into MRFs can improve the performance of MRFs.     

Kinetics of Fe(3)O(4)-CoO/Al(2)O(3) catalytic ozonation of the herbicide 2-(2,4-dichlorophenoxy) propionic acid

The presence of Fe(3)O(4)-CoO/Al(2)O(3) can improve degradation efficiency significantly during the ozonation of the herbicide 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP). The main factors affecting degradation efficiency, such as pH, the catalyst concentration and addition of the scavenger, were investigated. The kinetics of the catalytic ozonation are also discussed. The results indicate that two factors, the oxidation after adsorption of 2,4-DP and the oxidation of hydroxyl radicals (OH), lead to a great enhancement in ozonation efficiency during the catalytic ozonation of 2,4-DP in the presence of Fe(3)O(4)-CoO/Al(2)O(3), in which the oxidation of the OH plays an important role. Under controlled conditions, the apparent reaction rate constants for the degradation of 2,4-DP were determined to be 2.567 × 10(-4)s(-1) for O(3) and 1.840 × 10(-3)s(-1) for O(3)/Fe(3)O(4)-CoO/Al(2)O(3). The results from the analysis of the reaction kinetics using the relative method showed that O(3)/Fe(3)O(4)-CoO/Al(2)O(3) possessed a larger R(ct) (R(ct) is defined as the ratio of the ·OH exposure to the O(3) exposure, R(ct) = ∫C(t)(OH) dt/C(t)O(3)dt) than O(3), indicating that O(3)/Fe(3)O(4)-CoO/Al(2)O(3) produced more hydroxyl radicals.     

Fe-EDTA Thermal Decomposition,a Route to Highly Crystalline Hematite (Alpha Fe2O3) Nanoparticle Synthesis

In this study, we develop an experimental procedure to synthesize hematite nanoparticles by hydrothermal decomposition of Fe-EDTA complex in the presence of hydrogen peroxide, starting from ferric ammonium sulfate and Na ₄ EDTA as main precursors. The product was investigated by X-ray diffraction, scaning electron microscopy, dispersive X-ray spectroscopy, magnetic measurements, and UV-vis optical absorption measurements. The size of nanoparticles was determined to be 42 nm evaluated by XRD patterns using the Scherrer equation. This method allowed the formation of pure hematite nanoparticles with good and stable crystallographic characteristics. This procedure can be an effective method for synthesizing hematite nanoparticles exhibiting good crystallinity, stoichiometry, magnetic, and optical band gap properties. A possible mechanism for the formation of hematite nanocrystals was suggested.     

Enhanced photocatalytic activity of Fe3O4-WO3-APTES for azo dye removal from aqueous solutions in the presence of visible irradiation

Development of highly active photocatalysts for treatment of dye-laden wastewaters is vital. The photocatalytic removal of azo dye Reactive Black 5 was investigated by Fe₃O₄-WO₃-3-aminopropyltriethoxysilane (APTES) nanoparticles in the presence of visible light. The Fe₃O₄-WO₃-APTES nanoparticles were synthesized via a facile coprecipitation method. The photocatalyst was characterized by XRD, FT-IR, SEM, EDX, VSM, UV–Vis, and pH_PZC techniques. The effects of some operational parameters such as solution pH, nanophotocatalyst dosage, initial RB5 concentration, H₂O₂ concentration, different purging gases, and type of organic compounds on the removal efficiency were studied by the Fe₃O₄-WO₃-APTES nanoparticles as a photocatalyst. Maximum phtocatalytic activity was obtained at pH 3. The photocatalytic removal of RB5 increased with increasing H₂O₂ concentration up to 5?mM. The removal efficiency declined in the presence of different purging gases and all types of organic compounds. First-order rate constant (k_obs) decreased from 0.027 to 0.0022?min^?1 and electrical energy per order (E_Eo) increased from 21.33 to 261.82 (kWh/m³) with increasing RB5 concentration from 10 to 100?mg/L, respectively. The efficiency of LED/Fe₃O₄-WO₃-APTES process for RB5 removal was approximately 89.9%, which was more effective than the LED/Fe₃O₄-WO₃ process (60.72%). Also, photocatalytic activity decreased after five successive cycles.     

Application of multi-functional chestnut shell in one-step preparing Fe3O4@C magnetic nanocomposite with high adsorption performance

Chestnut shell (CS) acts as a multi-functional material in the one-step preparation of Fe₃O₄@C nanocomposite via hydrothermal method by using Fe(NO₃)₃ as Fe source without adding any other additives. The characterized results show that under required hydrothermal conditions, a proper amount of CS can reduce a certain amount of adsorbed/enriched Fe³⁺ to Fe²⁺ to ensure the 2:1 molar ration of Fe³⁺ to Fe²⁺ and the in-situ formation of goal phase Fe₃O₄ on the surface of the CS. Meanwhile, CS is carbonized to C material similar to graphene oxide. In the preparation process of the composite of Fe₃O₄@C, CS plays multiple roles, such as promoter, reductive agent, C-source, and template, to endow a certain morphology of the nanocomposite Fe₃O₄@C. The composite material shows good magnetic separability and adsorption property for methylene blue (MB) solution. Furthermore, the adsorptive kinetic behavior of the Fe₃O₄@C is investigated. The method is simple, fast, low cost and green and really realizes the full use of wasteful resource CS.     

Fe3O4磁性纳米粒子表面修饰研究进展

表面修饰Fe3O4磁性纳米粒子因具有优异的磁学特性、良好的生物相容性和丰富的化学反应可选择性,在生物医药领域如磁共振成像、组织修复、免疫测定、热疗、药物传递和细胞分离中显示了巨大的应用潜力.Fe3O4磁性纳米粒子的表面修饰主要包括以下3类:①有机小分子修饰,主要是偶联剂和表面活性剂修饰;②有机高分子修饰,包括天然生物大分子、合成高分子以及两者复合修饰;③无机纳米材料修饰,主要是SiO2、Au和Ag修饰.并就这三大方面的研究进展做了综合概述.     

羧甲基纤维素-Fe_3O_4复合纳米磁性材料的制备及其渗透性能

采用改进的氧化沉淀法在羧甲基纤维素(CMC)溶液中制备了以磁性纳米Fe3O4为核心,外包CMC的复合磁性纳米粒子。用透射电镜、X射线衍射、红外光谱、Zeta电位和震动样品磁强计对复合粒子进行了表面形貌、结构和磁学的表征。实验结果表明,CMC-Fe3O4复合纳米粒子为反尖晶石型,平均粒径约为40 nm;CMC在Fe3O4粒子表面是化学吸附;在相同pH值下,CMC-Fe3O4的表面Zeta电位低于纯相Fe3O4;CMC-Fe3O4的饱和磁化强度为36.74 emu.g-1;CMC-Fe3O4复合粒子在土壤介质中的过滤系数约为0.03 cm-1;在10 cm土柱渗透实验中,72%的CMC-Fe3O4复合粒子悬浊液穿过了土壤介质。