超小型Fe3O4/Au纳米复合微粒的制备与表征

用反向微乳液法成功制备了超小型Fe3O4/Au磁性纳米复合微粒,并利用3-巯基丙酸将复合微粒直接从微乳液分离到有机溶剂中.用UV-Vis、VSM和TEM对产物进行了鉴定与表征,结果表明复合微粒分散良好,平均粒径为6.7nm,饱和磁化强度为9.7A·m2/kg.     

Prussian blue modified Fe3O4 nanoparticles for Cs detoxification

Fe₃O₄ nanoparticles were surface modified with Prussian blue (PB) and the nanoparticles were used for the removal of cesium (Cs) ion. The attachment of PB with the Fe₃O₄ and their morphology were explained based on the studies by transmission electron microscope and BET measurements. The Cs ion adsorption studies have shown that the Cs removal efficiency reached maximum within 120 min. The adsorption kinetics studies using Lagergren pseudo-first-order kinetic model suggest the values of the amount of metal ion adsorbed at equilibrium (q _e) and adsorption rate constant (k ₁) as 22 mg/g and 0.015 min^?1, respectively. The capture efficiency of the prepared nanoparticles was studied by varying the flow channel diameter, applied magnetic field, and the fluid flow velocity. The study suggests that PB-Fe₃O₄ nanoparticles could be used for the detoxification of Cs where the flow velocity is in the range of few tens of cm/s.     

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.     

Fe304／Au复合纳米材料的制备及SERS研究

采用化学共沉淀法制备Fe3O4,通过对Fe3O4的表面处理后,将纳米金组装在Fe3O4表面,制备Fe3O4／Au复合磁性纳米材料。利用透射电子显微镜（TEM）对复合磁性纳米材料的形貌进行了表征,通过紫外一可见吸收光谱和拉曼光谱仪对磁性纳米材料的表面增强拉曼散射光谱进行表征研究,采用铷硼磁铁对磁性纳米材料的磁性进行初步研究。实验结果表明：复合磁性纳米颗粒既具有磁性又具有贵金属光谱特性;纳米金能很好地改善Fe3O4磁性纳米颗粒的表面增强拉曼散射活性。     

Fe3O4/Ni复合纳米颗粒的制备及其微波吸收特性

采用电爆炸技术,合成了粒径约为70nm 的Ni纳米颗粒,以3-巯基丙基三甲氧基硅烷偶联剂(MPTS)对Ni颗粒进行表面改性,利用共沉淀法对改性Ni颗粒进行包覆得到核-壳结构的复合纳米颗粒。将获得的复合纳米颗粒作为微波吸收剂, 并以不同比例分散到热固性酚醛树脂中,涂刷在200mm×200mm的金属板上,用RAM反射率远场RCS测量法研究了微波吸收特性。研究表明,核-壳结构Fe₃O₄/Ni复合颗粒作为微波吸收剂,在相同质量比条件下,其微波吸收性能明显优于纯Ni纳米颗粒或Fe₃O₄纳米颗粒的情况,并且在Fe₃O₄/Ni核-壳结构复合纳米颗粒中随着镍含量的提高,微波吸收增强,而随着Fe₃O₄含量的增加,微波吸收频段向高频段移动。     

O-羧甲基化壳聚糖修饰磁性Fe3O4纳米粒子及其生物应用

采用共沉淀法制备Fe3O4纳米粒子,用XRD测定粒子成分,用透射电镜和显微镜观测粒子形貌,用震动样品磁场计测定Fe3O4粉末饱和磁化强度,再以O-羧甲基化壳聚糖修饰后,用红外光谱检测粒子成分.粒子性能良好,能很好的应用于生物分离,连接等.     

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.     

Fe3O4/CdS纳米复合微粒的合成及性能研究

用反相微乳液法合成Fe3O4/CdS纳米复合微粒.用UV-Vis、PL、VSM和TEM对产物进行了表征,并对其结合机理进行了简单分析,认为主要以化学键结合和表面类齿轮切合作用所致.还研究了不同的合成条件对复合材料性能的影响.结果表明,随着微乳液水核尺寸增大,荧光发射光谱逐渐红移,同时壳层厚度先增后减.复合材料中磁性组份比重过大会引起荧光的迅速减弱,磁性先驱物与量子点先驱物物质的量比为0.25～0.5时比较合适.     

Fe3O4纳米粒子的制备与超顺磁性

采用红外光谱、X射线衍射、透射电子显微镜和振动样品磁强计对用化学共沉淀法制备出的纳米Fe3O4粒子进行了形貌、结构及磁性能表征.其中,红外和XRD测试结果表明制备出的Fe3O4粒子的物态和晶相结构;透射电子显微镜照片表明制备出的纳米四氧化三铁成球性好,且大部分四氧化三铁粒子的粒径在10nm左右;磁化曲线表明制备出的Fe3O4粒子无剩磁和矫顽力,具有超顺磁性.并且,将制备出的纳米Fe3O4粒子和块状Fe3O4的磁性能进行对比,探讨了Fe3O4由块状的亚铁磁性向纳米级的超顺磁性转变的原因.     

Ni doped Fe3O4 magnetic nanoparticles

In this work, the effect of nickel doping on the structural and magnetic properties of Fe3O4 nanoparticles is analysed. Ni(x)Fe(3-x)O4 nanoparticles (x = 0, 0.04, 0.06 and 0.11) were obtained by chemical co-precipitation method, starting from a mixture of FeCl2 x 4H2O and Ni(AcO)2 x 4H2O salts. The analysis of the structure and composition of the synthesized nanoparticles confirms their nanometer size (main sizes around 10 nm) and the inclusion of the Ni atoms in the characteristic spinel structure of the magnetite Fe3O4 phase. In order to characterize in detail the structure of the samples, X-ray absorption (XANES) measurements were performed on the Ni and Fe K-edges. The results indicate the oxidation of the Ni atoms to the 2+ state and the location of the Ni2+ cations in the Fe2+ octahedral sites. With respect to the magnetic properties, the samples display the characteristic superparamagnetic behaviour, with anhysteretic magnetic response at room temperature. The estimated magnetic moment confirms the partial substitution of the Fe2+ cations by Ni2+ atoms in the octahedral sites of the spinel structure.     

Deposition and Magnetic Properties of Fe3O4/Fe/Fe3O4Tri-layer Films

1. IntroductionIron oxides include several crystalline forms:hematite (or-FeZO3), magnetite (Fe3O4), maghemite(7-Felon) and wustite (FeO). They have interesting structural and magnetic properties, and are practically important in magnetic and electronic applications. The strongly ferrimagnetic 7--FeZO3 phaseearned much attention due to their applications asrecording media. The attainment of 7-FeZO3 involves complicated processing[1]. In our previousstudies, high coercivity 7-FeZO3, Fe3…     

Fe3O4／羧甲基化壳聚糖纳米粒子的制备与表征

磁性壳聚糖纳米粒子可用于药物载体及废水处理吸附剂。以化学共沉淀法制备Fe3O4纳米粒子，壳聚糖先进行羧甲基化改性，再经碳二亚胺活化，包履在Fe3O4颗粒表面,透射电镜（TEM）表明，Fe3O4纳米粒子被CMC包履，粒径约10nm；X射线衍射（XRD）分析表明复合纳米粒子中磁性物质为Fe3O4；傅立叶红外光谱（FTIR）表明壳聚糖发生羧甲基反应；磁性测试表明，Fe3O4／CMC具有超顺磁性，饱和磁化强度25.73emu／g，且有良好的磁稳定性。     

Fe3O4纳米粒子的磷酸胆碱仿细胞膜修饰

用水相共沉淀法制备了超顺磁的Fe3O4纳米粒子,并通过Michael加成将2-(甲基丙烯酰氧基)乙基-2-(三甲基氨基)乙基磷酸酯(MPC)共价键合到氨基化的Fe3O4纳米粒子表面.与未修饰MPC的Fe3O4纳米粒子相比,修饰了MPC的纳米粒子能大大减少蛋白质的非特异性吸附,延长了复钙化凝血时间,并具有良好的生物相容性.     

Fe3O4磁性纳米颗粒的合成及其调控

利用水解共沉淀法制备了Fe3O4纳米颗粒,研究了温度和pH值对Fe3O4纳米颗粒粒径、形貌的影响关系。研究结果表明,反应温度从30℃升高到90℃,Fe3O4颗粒的粒径从6～8nm增大到10～12nm;同时,Fe3O4颗粒的饱和磁矩也随着Fe3O4颗粒粒径的增加而升高。溶液pH值会影响Fe3O4纳米颗粒的形状,高pH值易使合成的Fe3O4纳米颗粒为四方形,随着pH值的降低,Fe3O4纳米颗粒向球形转变。Fe3O4纳米颗粒的粒径和形状的可控性为进一步合成、调控Fe3O4电磁功能复合材料奠定了良好基础。     

Synthesis and magnetic properties of Fe3O4 nanoparticles

Ferromagnetic Fe₃O₄ nanoparticles with diameter of ∼27 nm were prepared by a hydrothermal route in the presence of a surfactant, sodium bis(2-ethylhexyl)sulfosuccinate (AOT). The as-synthesized product was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The hysteresis loops of the iron oxide nanoparticles were measured using a physical property measuring system (PPMS), and the results showed a superparamagnetic behavior at room temperature.     

Enhancement of methane production by Methanosarcina barkeri using Fe3O4 nanoparticles as iron sustained release agent

Anaerobic digestion has attracted attention because it does not require power for aeration, it reduces excess sludge and it generates methane gas. However, the growth rate of anaerobic microorganisms is slow, resulting in low treatment efficiency. In this study, the impact of Fe₃O₄ nanoparticles (NPs) on the growth of methanogens, which is the rate-determining step in anaerobic digestion, was investigated using a pure culture of Methanosarcina barkeri as the model methanogen. M. barkeri were cultivated in iron free medium, as well as in media amended with various concentrations of Fe₃O₄ NPs with a mean diameter of 8.1?±?2.4?nm. The production of methane gas was greatly increased when organisms were cultured in media containing NPs. After the methane production was saturated, methanol was newly added to the culture, which resulted in additional methane generation at a higher production rate than occurred during the initial round of cultivation in media containing 20?ppm Fe₃O₄ NPs. In addition, no evidence of negative impacts of Fe₃O₄ NPs on the growth of M. barkeri was observed. Taken together, these results strongly suggest that adding Fe₃O₄ NPs into the fermenter as an agent of sustained iron release can enable sustainable methane fermentation.     

化学还原法制备Fe3O4纳米颗粒及其性能研究

采用化学还原法制备得到了Fe3O4纳米颗粒,并用XRD对制备条件:分散剂种类、分散剂用量、煅烧温度、煅烧时间进行了研究。研究结果表明,当选用PEG(6000)做分散剂,PEG用量为50g/L,煅烧温度为700℃,煅烧时间为120min时,制备得到的Fe3O4纳米颗粒已经具有晶型完整的反尖晶石结构。将该样品做VSM分析,分析结果表明样品饱和磁化强度可达85A.m2/kg,并且矫顽力趋近于0,呈现出良好的顺磁性。     

Tuning exchange bias in core/shell FeO/Fe3O4 nanoparticles

Monodisperse 35 nm FeO nanoparticles (NPs) were synthesized and oxidized in a dry air atmosphere into core/shell FeO/Fe(3)O(4) NPs with both FeO core and Fe(3)O(4) shell dimensions controlled by reaction temperature and time. Temperature-dependent magnetic properties were studied on FeO/Fe(3)O(4) NPs obtained from the FeO NPs oxidized at 60 and 100 °C for 30 min. A large exchange bias (shift in the hysteresis loop) was observed in these core/shell NPs. The relative dimensions of the core and shell determine not only the coercivity and exchange field but also the dominant reversal mechanism of the ferrimagnetic Fe(3)O(4) component. This is the first time demonstration of tuning exchange bias and of controlling asymmetric magnetization reversal in FeO/Fe(3)O(4) NPs with antiferromagnetic core and ferrimagnetic shell.     

Magnetoresponsive on-demand release of hybrid liposomes formed from Fe3 O4 nanoparticles and thermosensitive block copolymers

A new approach to control the release of encapsulated materials from liposomes by using thermosensitive block copolymers and magnetic nanoparticles is reported. Hydrophobized Fe(3) O(4) nanoparticles are synthesized via the hydrothermal process, and can be incorporated into liposomal membranes by hydrophobic interactions. Thermosensitive block copolymers of (2-ethoxy)ethoxyethyl vinyl ether (EOEOVE) and octadecyl vinyl ether (ODVE) are synthesized by living cationic polymerization. The poly(EOEOVE) block acts as a temperature-sensitive moiety, and the poly(ODVE) block acts as an anchor unit. Hybrid liposomes encapsulating pyranine, a water-soluble fluorescent dye, are prepared from mixtures of phospholipids, the hydrophobized Fe(3) O(4) nanoparticles, and the copolymer. While the hybrid liposomes released negligible amounts of pyranine under static conditions, the release of pyranine is drastically enhanced by alternating magnetic field irradiation. The magnetically induced release is attributed to the transition of the thermosensitive segment of the copolymer, which is caused by the release of localized heat from the Fe(3) O(4) nanoparticles under magnetic stimuli, rather than the rupture of the capsules. The release rate of the hybrid capsules is controlled by varying the amount of Fe(3) O(4) nanoparticles embedded into the liposomes.