交联P（St-r-AA）包覆Fe3O4粒子的制备及对Cu2＋的吸附

用乳液聚合的方法合成了交联P（St-r-AA）包覆的Fe3O4粒子,研究了该类粒子对Cu2＋离子的吸附性能。透射电镜（TEM）表明,交联的P（St-r-AA）包覆的Fe3O4磁性粒子粒径约100 nm;X射线衍射（XRD）分析表明,磁性粒子中磁性物质为尖晶石结构的Fe3O4;红外光谱（FT-IR）表明,Fe3O4表面的...     

水溶性PEO—PPO—PEO包裹Fe3O4纳米微粒的可控制备

以聚氧乙烯-聚氧丙烯-聚氧乙烯三嵌段共聚物（PEO—PPO—PEO）作表面活性剂,采用纳米微乳液法还原Fe（Ⅱ）-乙酰丙酮化合物（Fe^Ⅱ（acac）2）,制备粒径可控、单分散、水溶性Fe3O4纳米微粒,并进行了相关的表征测试。从傅里叶变换红外光谱（FTIR）中可以看出,共聚物PEO—PPO—PEO包裹在Fe3O4纳米微粒表面;透射电镜（TEM）显示纳米颗粒分散性好,呈球形;高斯拟合表明,不同物料配比合成的Fe3O4粒子大小、粒径分布不同;振动样品磁强计（VSM）测试说明,Fe3O4纳米颗粒室温下为超顺磁性或软铁磁性。由于PEO-PPO—PEO具有亲水性,PEO—PPO—PEO包裹的Fe3O4纳米微粒不用进一步处理即可转移到水相中,在生物和医学领域具有重要的潜在应用价值。     

Synthesis of size-controlled Fe3O4@SiO2 magnetic nanoparticles for nucleic acid analysis

We present a systematic study on the preparation, characteration and potential application of Fe3O4 and Fe3O4@SiO2 nanoparticles. Fe3O4 nanoparticles of controllable diameters were successfully synthesized by solvothermal system with tuning pH. The magnetic properties of nanoparticles were measured by vibration sample magnetometer. Fe3O4@ SiO2 nanoparticles were obtained via classic St?ber process. Streptavidin coated Fe3O4@SiO2 nanoparticles were prepared by covalent interaction. The quantity of streptavidin bound to nanoparticles was determined by UV-Vis spectrometer. To evaluate the binding efficiency and capacity of nucleic acid on nanoparticles, the capture of biotinylated oligonucleotide on streptavidin coated Fe3O4@SiO2 nanoparticles at different concentration was estimated by fluorescence detection. Both Fe3O4 and Fe3O4@SiO2 nanoparticles exhibited well crystallization and magnetic properties. The maximal amount of streptavidin immobilized onto the Fe3O4@SiO2 nanoparticles was 29.3 microg/mg. The saturation ratio of biotinylated oligonucleotides captured on streptavidin coated Fe3O4@SiO2 nanoparticles was 5 microM/mg within 20 minutes, indicating that FeO4@SiO2 nanoparticles immobilized by streptavidin were excellent carriers in nucleic acid analysis due to their convenient magnetic-separation property. Therefore, the synthesized Fe3O4 and Fe3O4@SiO2 nanoparticles with controllable size and high magnetic saturation have shown great application potentials in nucleic acid research.     

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。     

Mesoporous multifunctional upconversion luminescent and magnetic "nanorattle" materials for targeted chemotherapy

Nanorattles consisting of hydrophilic, rare-earth-doped NaYF(4) shells each containing a loose magnetic nanoparticle were fabricated through an ion-exchange process. The inner magnetic Fe(3)O(4) nanoparticles are coated with a SiO(2) layer to avoid iron leaching in acidic biological environments. This multifunctional mesoporous nanostructure with both upconversion luminescent and magnetic properties has excellent water dispersibility and a high drug-loading capacity. The material emits visible luminescence upon NIR excitation and can be directed by an external magnetic field to a specific target, making it an attractive system for a variety of biological applications. Measurements on cells incubated with the nanorattles show them to have low cytotoxicity and excellent cell imaging properties. In vivo experiments yield highly encouraging tumor shrinkage with the antitumor drug doxorubicin (DOX) and significantly enhanced tumor targeting in the presence of an applied magnetic field.     

纳米Fe3O4/聚苯胺复合粒子的制备及其在交变磁场下的发热性能

用水解沉淀法合成了纳米Fe₃O₄粒子,并在其悬浮液中原位包覆聚苯胺,制备出纳米Fe₃O₄/聚苯胺复合粒子。研究了两种纳米粒子在交变磁场下的发热性能,对它们在定向集热治疗肿瘤中的应用前景进行了评价。纳米Fe₃O₄粒子的粒径为10~30nm,表面包覆聚苯胺后,复合粒子的粒径为30~50nm。纳米Fe₃O₄粒子的比饱和磁化强度为50.05Am2/kg,矫顽力为10.9kA/m;纳米Fe₃O₄/聚苯胺复合粒子的比饱和磁化强度为26.34Am2/kg,矫顽力为0。在10mg/mL的生理盐水悬浮液中,在外加交变磁场作用30min后,纳米Fe₃O₄粒子悬浮液的温度为63.6℃,纳米Fe₃O₄/聚苯胺悬浮液的温度为52.4℃,二者均达到了医学上定向集热治疗肿瘤用热籽的发热要求,是很有应用前景的医用纳米材料。      

纳米Fe_3O_4/Fe复合磁流变液的流变性

用化学共沉淀法合成了纳米Fe3O4粒子,平均二次粒径为51.2nm,比表面积为109.6m2/g。以合成的纳米Fe3O4粒子与羰基铁粉复合配制了纳米复合磁流变(MR)液,并测定了其流变性。结果显示:纳米复合MR液对温度比较稳定;复合MR液在接近零场的低磁场强度下表现为牛顿流体,随着磁场强度提高转变为非牛顿流体;反复加载或撤除磁场,具有"开/关"特性,响应迅速,施加磁场时的响应时间Δt约为50～100ms,撤退磁场时约为100～150ms。     

Synthesis and characterization of SiO2/(PMMA/Fe3O4) magnetic nanocomposites

Magnetic silica nanocomposites (magnetic nanoparticles core coated by silica shell) have the wide promising applications in the biomedical field and usually been prepared based on the famous St?ber process. However, the flocculation of Fe3O4 nanoparticles easily occurs during the silica coating, which limits the amount of magnetic silica particles produced in the St?ber process. In this paper, PMMA/Fe3O4 nanoparticles were used in the St?ber process instead of the "nude" Fe3O4 nanoparticles. And coating Fe3O4 with PMMA polymer beforehand can prevent magnetic nanoparticles from the aggregation that usually comes from the increasing of ionic strength during the hydrolyzation of tetraethoxysilane (TEOS) by the steric hindrance. The results show that the critical concentration of magnetic nanoparticles can increase from 12 mg/L for "nude" Fe3O4 nanoparticles to 3 g/L for PMMA/Fe3O4 nanoparticles during the St?ber process. And before the deposition of silica shell, the surface of PMMA/FeO4 nanoparticles had to be further modified by hydrolyzing them in CH3OH/NH3 x H2O mixture solution, which provides the carboxyl groups on their surface to react further with the silanol groups of silicic acid.     

Supraparamagnetic, conductive, and processable multifunctional graphene nanosheets coated with high-density Fe3O4 nanoparticles

The amazing properties of graphene are triggering extensive interests of both scientists and engineers, whereas how to fully utilize the unique attributes of graphene to construct novel graphene-based composites with tailor-made, integrated functions remains to be a challenge. Here, we report a facile approach to multifunctional iron oxide nanoparticle-attached graphene nanosheets (graphene@Fe(3)O(4)) which show the integrated properties of strong supraparamagnetism, electrical conductivity, highly chemical reactivity, good solubility, and excellent processability. The synthesis method is efficient, scalable, green, and controllable and has the feature of reduction of graphene oxide and formation of Fe(3)O(4) nanoparticles in one step. When the feed ratios are adjusted, the average diameter of Fe(3)O(4) nanoparticles (1.2-6.3 nm), the coverage density of Fe(3)O(4) nanoparticles on graphene nanosheets (5.3-57.9%), and the saturated magnetization of graphene@Fe(3)O(4) (0.5-44.1 emu/g) can be controlled readily. Because of the good solubility of the as-prepared graphene@Fe(3)O(4), highly flexible and multifunctional films composed of polyurethane and a high content of graphene@Fe(3)O(4) (up to 60 wt %) were fabricated by the solution-processing technique. The graphene@Fe(3)O(4) hybrid sheets showed electrical conductivity of 0.7 S/m and can be aligned into a layered-stacking pattern in an external magnetic field. The versatile graphene@Fe(3)O(4) nanosheets hold great promise in a wide range of fields, including magnetic resonance imaging, electromagnetic interference shielding, microwave absorbing, and so forth.     

Fast and selective removal of oils from water surface via highly hydrophobic core-shell Fe2O3@C nanoparticles under magnetic field

The removal of oil spills or organic contaminants from water surface is of great technological importance for environmental protection. A major challenge is the fast distribution and collection of absorbent materials with high separation selectivity, good thermal stability, and excellent recyclability. Here we reported fast and selective removal of oils from water surface through core-shell Fe(2)O(3)@C nanoparticles under magnetic field. These nanoparticles combined with unsinkable, highly hydrophobic and superoleophilic properties, could selectively absorb lubricating oil up to 3.8 times of the particles' weight while completely repelling water. The oil-absorbed nanoparticles were quickly collected in seconds by applying an external magnetic field. More importantly, the oil could be readily removed from the surfaces of nanoparticles by a simple ultrasonic treatment whereas the particles still kept highly hydrophobic and superolephilic characteristics. Experiment results showed that the highly hydrophobic Fe(2)O(3)@C nanoparticles could be reused in water-oil separation for many cycles. Our results suggest a facile and efficient method that might find practical applications in the cleanup of oil spills and the removal of organic pollutants on water surface.     

A novel route to prepare Fe3O4/P(MAA-co-NVP) cross-linked magnetic composite microspheres with core-shell architecture by surface-initiated radical dispersion polymerization

A novel route was proposed to design and construct a magnetic composite microsphere with a controllable and regular core-shell architecture, which consists of Fe3O4 nanoparticles chemical-covalently encapsulated with pH-smart poly(methacrylic acid-co-N-vinyl pyrrolidone) (P(MAA-co-NVP)) cross-linked copolymers by a surface-initiated radical dispersion polymerization approach. The multistep surface treatment was employed to improve the dispersity and surface-chemical reactivity of Fe3O4 nanoparticles, involving introduction of active -NH2 groups, coupling of 1,1-methylene bis-(4-isocyanato-cyclohexane) and immobilizing of 2,2'-azobis[2-methyl-N-(2-hydroxyethyl) propionamide]. The structure and morphological characterization were carried out by FTIR, TEM, SEM and XRD etc. The neat Fe3O4 nanoparticles take on an aggregated spherical shape with an average diameter of about 12 nm, while Fe3O4/P(MAA-co-NVP) magnetic microspheres assume regularly monodispersed spheres with a mean dimension of ca. 0.8 microm. The dimension of the microspheres is abruptly increased with increasing pH values of the media. The microspheres exhibit superparamagnetic properties. It is expected that this type of novel microspheres can be employed as a magnetic targeted and pH-sensitive drug carrier.     

表面活性剂对磁流体稳定性及外层包覆结构的影响

采用化学共沉淀法制备粒径分布均匀的纳米Fe3O4颗粒,用油酸钠和聚乙二醇4000(PEG4000)对纳米Fe3O4颗粒进行表面修饰,制得分散稳定的纳米Fe3O4磁流体,通过电动电位(Zeta电位)、粒径测试、离心沉淀、红外光谱分析(FT-IR)和热分析(TG)对修饰后的纳米Fe3O4颗粒进行了稳定性能评价与结构表征。结果表明,油酸钠与纳米Fe3O4颗粒存在两种不同类型的化学键作用;增大油酸钠加入量不会改变Fe3O4颗粒表面包覆结构,但是,其在纳米Fe3O4颗粒表面的吸附量呈先增加后降低的趋势;PEG4000物理吸附于油酸钠包覆的纳米Fe3O4颗粒表面,PEG4000的加入会进一步提高磁流体的稳定性。     

Fe3O4@Au@Ag复合纳米材料的制备及SERS研究

用化学共沉淀法制备Fe3O4,用静电吸附法制备Fe3O4@Au复合磁性纳米材料,用种子生长法制备出Fe3O4@Au@Ag复合磁性纳米材料。利用紫外一可见吸收光谱研究复合磁性纳米颗粒的光谱特性,以结晶紫为探针分子检测磁性纳米颗粒的表面增强拉曼散射光谱。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;复合磁性纳米颗粒能很好地改善Fe3O4磁性纳米颗粒的表面增强拉曼散射活性。     

静电纺丝法制备PAN/Fe3O4磁性纳米纤维

采用化学共沉淀法制备纳米四氧化三铁,选用曲拉通X-100为分散剂,利用静电纺丝法制备PAN/Fe3O4磁性纳米复合材料。X射线衍射仪(XRD)验证了四氧化三铁在复合纳米纤维中的存在。同时使用扫描电镜(SEM)和透射电镜(TEM)对复合纳米纤维的微观形貌和Fe3O4在纤维中的分布进行了观察,利用热重(TGA)对纳米复合材料的热稳定性进行分析;通过磁性实验分析了纳米复合材料的磁性性能。结果表明,所制备PAN/Fe3O4磁性纳米纤维成型良好,且Fe3O4磁性颗粒在纤维中分散均匀,其与PAN是物理复合。纳米复合材料具有一定磁性,并可由磁性颗粒的加入量进行控制。     

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。     

Fe3O4/羧基改性壳聚糖复合纳米粒子的制备、表征及生物学应用

采用氧化水热法,以H2O2为氧化剂制备了磁性Fe3O4纳米颗粒.以磁性Fe3O4为核,通过反相悬浮聚合法对Fe3O4颗粒表面进行改性,在碳二亚胺的活化作用下,与壳聚糖衍生物-α-酮戊二酸缩壳聚糖(KCTS)反应制备了表面含有一定羧基的磁性Fe3O4/KCTS纳米粒子.经XRD、TEM、VSM、IR、TGA等手段对复合材料进行了表征及性能研究.结果表明,该磁性Fe3O4/KCTS纳米粒子的平均粒径为26nm,比饱和磁化强度为24.8A·m2/kg.其性能优良,具备超顺磁性,能很好的应用于生物分离,蛋白吸附等领域.     

The effect of the strength and direction of magnetic field on the assembly of magnetic nanoparticles into higher structures

The self-assembly of magnetic nanoparticles into higher-order organizations upon external magnetic stimulation has critical importance for the fabrication of discrete microstructures. In this study, the tuning of self-assembly behavior of magnetic Fe3O4 nanoparticles (MNPs), with an average size of 6 nm, under the enhanced magnetic force upon changing the applied field strength and direction is explored. Upon evaporation of the solvent where the MNPs are suspended, formation of particular micrometer sized structures is achieved with a surface constructed from sub-micrometer size magnetic beads in between the applied magnetic field and MNPs. In this study, three different surfaces fabricated using sub-micrometer size magnetic beads in between the applied magnetic field and MNPs are used and the effect of the template pattern, applied field strength and direction are explored.     

A novel nanoscale catalyst system composed of nanosized Pd catalysts immobilized on Fe(3)O(4)@SiO(2)-PAMAM

This study reports the syntheses of Fe(3)O(4)@SiO(2)-Gn-PAMAM-Pd(0) composites and their applications as magnetically recoverable catalysts for the hydrogenation of allyl alcohol. The controlled growth of polyamidoamine (PAMAM) dendrimers with different generations on Fe(3)O(4)@SiO(2) surfaces was monitored by FT-IR spectra. Subsequently, Pd nanoparticles with diameters of about 2.5?nm were stabilized homogeneously on the surface of Fe(3)O(4)@SiO(2)-Gn-PAMAM (n = 1-4), investigated by thermogravimetry (TG) and transmission electron microscopy (TEM) measurements. The?Fe(3)O(4)@SiO(2)-Gn-PAMAM-Pd(0) have high catalytic activity for the hydrogenation of allyl alcohol and the rate of the reaction can be controlled by changing the generation of PAMAM. In particular, the composites made of superparamagnetic Fe(3)O(4) nanocrystals with diameters of about 10?nm are very suitable as catalyst supports for catalyst separation under a relatively low external magnetic field and catalyst re-dispersion after removing the external magnetic field.     

酞菁钴-Fe_3O_4纳米复合粒子的表征及其电磁流变液的研究

制备了粒径为微米级的酞菁钴（CoPc）－Fe3O4纳米复合粒子,并用它与氯化石蜡油组成了活性较高的无水电磁流变（EMR）液,同时用IR、XRD、SEM对（CoPc）－Fe3O4纳米复合粒子进行了表征。结果表明,CoPc在Fe3O4纳米粒子表面形成了单层分散层,其阈值（最大单层分散容量）为0．06gCoPcc／g（Fe3O4）。CoPc通过一定程度的化学键作用与Fe3O4纳米粒子形成了有效的复合,提高了其抗氧化能力和稳定性。该EMR液既具有电流变效应又具有磁流变效应,当同时施加电场和磁场时,它表现出显著的协同效应。     

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.