CdTe@Fe3O4磁性复合纳米粒子的合成与表征

本文通过层层自组装技术（1ayer-by—layer,LBL）成功制备了CdTe@Fe3O4磁性荧光复合纳米粒子,并对其特性和应用进行了讨论．首先,采用化学共沉淀法,以NaOH为沉淀剂,Fe^2＋和Fe^3＋物质的量的比为1：2．在50℃水相中电磁搅拌30min,制备出具有磁性的纳米Fe3O4,然后表面修饰1,6-己二胺．通过透射电镜（transmission electron microscopy,TEM）对其进行观察,粒径在10nm左右．核壳cdTe@Fe3O4复合功能纳米粒子的合成表明：Fe3O4和cdTc物质的量的比为1：3,pH=6．0,温度30℃,反应时间30min为其最佳合成条件．通过TEM、紫外和荧光光谱对合成的纳米粒子分别进行了表征．cdTe@Fe3O4粒径在12～15nm,最大发射波长从530nm红移到570nm,而最大吸收波长则从530nm红移到535mm．结果表明,磁性Fe3O4表面成功覆盖了CdTe壳层．核壳型CdTe@Fe3O4磁性荧光复合纳米粒子的应用能够实现对DNA进行简便快捷的标记、传感和分离．     

磁性羧甲基化壳聚糖纳米粒子的制备与表征

以化学共沉淀法制备了Fe3O4纳米粒子,壳聚糖经羧甲基化改性后接枝在Fe3O4颗粒表面,得到了磁性羧甲基化壳聚糖(Fe3O4/CMC)纳米粒子.利用透射电镜(TEM)、X射线衍射(XRD)、傅立叶红外光谱(FT-IR)及磁性测试对产物进行了表征.TEM表明Fe3O4纳米粒子被CMC包覆,粒径约10 nm;XRD分析表明复合纳米粒子中磁性物质为Fe3O4;FT-IR表明壳聚糖发生羧甲基反应以及在Fe3O4表面的接枝反应.Fe3O4/CMC纳米粒子具有超顺磁性,比饱和磁化强度25.73 emu/g,有良好的磁稳定性.     

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。     

微波辐射乳液聚合制备聚氰基丙烯酸正丁酯磁性微球

通过化学共沉淀法制备Fe3O4纳米粒子,再用油酸钠和十二烷基磺酸钠(SDS)对Fe3O4进行改性,制得稳定的水基磁流体。在自制的磁流体存在下,以氰基丙烯酸正丁酯(BCA)为单体,用微波辐射乳液聚合的方法制备了Fe3O4/聚氰基丙烯酸正丁酯磁性微球。并用X射线衍射仪(XRD),透射电子显微镜(TEM),傅立叶红外光谱仪(FT-IR),振动样品磁强计(VSM)对制备的磁性高分子微球的结构形貌和磁性能进行表征测试。结果表明,在适当的pH值条件下,得到了粒径为150 nm~200 nm,饱和磁化强度为20.23 emμ/g,粒径均一的聚氰基丙烯酸正丁酯磁性微球。     

Preparation of guanidine group functionalized magnetic nanoparticles and the application in preconcentration and separation of acidic protein

Guanidine group (Gnd) functionalized magnetic nanoparticles (Fe3O4@SiO2@NH2-Gnd) were synthesized and characterized in this work for the first time. The characterization of Fe3O4@SiO2@ NH2-Gnd nanoparticles was demonstrated by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectra, vibration sample magnetometer, and zeta potential analyzer. The novel multifunctional nanoparticles were served as a solid-phase extraction sorbent for easy isolation and preconcentration of acidic protein from aqueous solution only using a magnet. Bovine serum albumin (BSA) was selected as a model protein and the main experimental parameters influencing the adsorption and desorption efficiency were investigated and optimized. Under the optimum conditions, the particles reached saturated adsorption within 20 min and exhibited significant specific recognition for the acidic proteins. Fifteen fold enrichment efficiency was achieved and the detection limits was 45 ng x mL(-1) for BSA by capillary electrophoresis (CE). The practical application of the novel nanoparticles as a sorbent for the isolation and preconcentration of acidic proteins from basic proteins was demonstrated by effective separation and enrichment of bovine serum albumin from lysozyme and cytochrome C mixture, which was assayed by CE.     

柠檬酸在磁性纳米粒子上的吸附及性能表征

采用柠檬酸对Fe3O4磁性纳米粒子进行表面改性,制备了高稳定性的水基磁流体.利用衰减全反射红外光谱(ATR-FTIR)、热重分析(TG)、透射电镜(TEM)、X射线衍射(XRD)和振动样品磁强计(VSM)对改性前后的磁性粒子进行了表征.结果表明,柠檬酸在Fe3O4表面的吸附是氢键、静电力和共价键共同作用的结果,pH为4.8时化学吸附达到最大,符合Langmuir等温吸附,建立了等温吸附方程,饱和吸附量为100mg/g.     

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 one-pot synthesis of dextran-based nanoparticles and their application in in-situ fabrication of dextran-magnetite nanocomposites

The dextran-based nanoparticles containing carboxyl groups were synthesized by a one-pot approach, without using any organic solvents and surfactants. The resultant dextran-based nanoparticles was used as a host for the growing and organization of Fe(3)O(4) nanoparticles. The approach consists of the mixture of ferrous/ferric ions aqueous solution and host nanoparticles and subsequent coprecipitation of ferrous/ferric ions in basic medium. The magnetic nanocomposite material obtained was characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), X-ray diffraction techniques (XRD) and vibrating sample magnetometry (VSM). The data demonstrate that the carboxyls which can capture cationic ferrous/ferric by electronic interaction in the dextran-based hosts plays a crucial role in fabricating nanocomposites with a homogeneous spatial distribution of magnetite nanoparticles. The magnetic nanocomposites exhibit comparable saturation magnetizations to that of reported Fe(3)O(4) nanoparticles, and therefore display great potential in a large scope of biomedical fields.     

Fe@Ag core-shell nanoparticles with both sensitive plasmonic properties and tunable magnetism

Monodisperse Fe@Ag core-shell nanoparticles with relatively uniform Fe cores and Ag shells have been successfully fabricated by a seed mediated method in a two-step reducing process, and then characterized by electron microscopy techniques (HRTEM, EDX), X-ray diffraction (XRD), UV-vis spectroscopy,and magnetometry. The results demonstrate unique optical and magnetic properties for Fe@Ag core-shell nanoparticles. The surface plasmon resonance of Fe@Ag core-shell nanoparticles is red shifted as compared with that of pure colloidal nano-silver, while the plasmon band of Fe@Ag core-shell nanoparticles with thinner Ag shells is shifted to a longer wavelength. Fe@Ag core-shell nanoparticles have a narrow plasmon band and therefore sensitive plasmonic properties. The magnetism of Fe@Ag nanoparticles can be tuned from superparamagnetic to ferromagnetic by modifying the proportion between Fe and Ag contents. The multifunctional Fe@Ag core-shell nanoparticles have potential in optoelectronic, spintronic, and biomedicine applications.     

Preparation and characterization of Ni-nitrilotriacetic acid bearing poly(methacrylic acid) coated superparamagnetic magnetite nanoparticles

Stable superparamagnetic magnetite (Fe3O4) nanoparticles were synthesized via co-precipitation in the presence of poly(methacrylic acid) (PMAA) in aqueous solution. The polymer coated Fe3O4 nanoparticles were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thermal analysis, and vibrating sample magnetometry (VSM) techniques. These measurements reveal the presence of magnetite nanoparticles with a size of approximately 8 nm inside the PMAA matrix. The magnetization value of these superparamagnetic nanoparticles at room temperarure and 7 T was measured as about 40 emu/g. PMAA-coated Fe3O4 nanoparticles were further assembled with Ni-chelate through a reaction between a primary amine-bearing NTA (nitrilotriacetic acid) ligand and carboxy-functional groups of PMAA. NTA-PMAA-coated magnetite nanoparticles were then loaded with nickel ions and characterized using FTIR. The average amount of binded Ni on the surface of the NTA-modified PMAA coated Fe3O4 was calculated as 1.65 +/- 0.3 x 10(-6) mol nickel(II) ions per g of the magnetic particles from the inductively coupled plasma optical emission spectroscopy (ICP-OES) measurements.     

Magnetic properties of encapsulated nanoparticles in nitrogen-doped multiwalled cabon nanotubes embedded in SiOx matrices

We report the production, characterization, thermal transformations (400-1000 degrees C), and magnetic properties of nanoparticles encapsulated in nitrogen-doped multiwall carbon nanotubes (CNx-MWNT), which were embedded in silicon oxide (SiOx) matrices via sol-gel techniques. The vapor chemical deposition (CVD) method with ferrocene-benzelamine mixtures was used to synthesize Fe and Fe3C nanoparticles inside CNx-MWNTs. Composites consisting of CNx-MWNTs (filler) and SiOx (matrix) were fabricated and thermally treated to different temperatures and exposure times (t). All samples were characterized using scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), thermogravimetic analysis (TGA), and magnetometry (vibrating sample). We found that upon thermal treatment, the ferromagnetic nanoparticles modify their morphology, composition and aspect ratio, thus resulting in drastic changes in the magnetic and structural properties. In particular, as produced encapsulated nanoparticles mainly consisting of Fe and Fe3C phases were thermally modified into magnetite (Fe3O4). We have also observed that the hysteresis loops are very sensitive to the thermal treatment of the sample. Thus we can control the magnetic properties of the samples using thermal treatments.     

Synthesis and characterization of magnetically active carbon nanofiber/iron oxide composites with hierarchical pore structures

Polyacrylonitrile (PAN) solution containing the iron oxide precursor iron (III) acetylacetonate (AAI) was electrospun and thermally treated to produce electrically conducting, magnetic carbon nanofiber mats with hierarchical pore structures. The morphology and material properties of the resulting multifunctional nanofiber mats including the surface area and the electric and magnetic properties were examined using various characterization techniques. Scanning electron microscopy images show that uniform fibers were produced with a fiber diameter of ～600?nm, and this uniform fiber morphology is maintained after graphitization with a fiber diameter of ～330?nm. X-ray diffraction (XRD) and Raman studies reveal that both graphite and Fe(3)O(4) crystals are formed after thermal treatment, and graphitization can be enhanced by the presence of iron. A combination of XRD and transmission electron microscopy experiments reveals the formation of pores with graphitic nanoparticles in the walls as well as the formation of magnetite nanoparticles distributed throughout the fibers. Physisorption experiments show that the multifunctional fiber mats exhibit a high surface area (200-400?m(2)?g(-1)) and their pore size is dependent on the amount of iron added and graphitization conditions. Finally, we have demonstrated that the fibers are electrically conducting as well as magnetically active.     

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。     

聚乙二醇法在温和条件下制备不同结构的磁性Fe3O4纳米晶

以Fe（acac）3为原料,乙二醇、聚乙二醇1000和聚乙二醇5000为还原剂和溶剂,在温和的溶剂热的条件下制备了不同尺寸的顺磁性Fe3O4纳米颗粒.利用X射线衍射（XRD）、光电子能谱（XPS）、透射电子显微镜（TEM）和磁性测量技术对制备的Fe3O4纳米颗粒的结构、形貌、磁性能进行了表征测试.结果发现,聚乙二醇分子链的长度对Fe3O4纳米颗粒的平均粒径大小、结晶度和饱和磁化强度均有重要影响.以乙二醇、聚乙二醇1000和聚乙二醇5000为还原剂制备的Fe3O4纳米颗粒的尺寸分别为2～3nm、5nm和7～8nm;相应的纳米Fe3O4颗粒饱和磁化强度分别为55.2、61.5和81.3emu/g;同时结晶度也随分子链的增加而增加.随分子链长度的增加,还原剂还原性的逐渐增加是导致Fe3O4纳米颗粒平均粒径大小、结晶度和饱和磁化强度逐渐增大的重要因素.     

磁性荧光纳米复合粒子的制备及其表面生物功能化

用化学共沉淀法制备了四氧化三铁(Fe3O4)纳米粒子,Stober法在其表面包裹SiO2并复合荧光标记物FITC,EDC偶联牛血清白蛋白(BSA)。采用扫描电子显微镜(SEM),傅里叶变换红外光谱仪(FT-IR),荧光分析仪,电子能谱(XPS)等对复合粒子进行了表征。结果表明,复合粒子保留了FITC的荧光特性、Fe3O4的磁响应性并成功接枝蛋白分子。生物功能化磁性荧光复合纳米粒子有望广泛应用于细胞标记、荧光追踪、磁性分离等领域。     

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.     

Synthesis and characterization of Fe/Nd2O3 core-shell nanoparticles by hydrogen plasma-metal reaction

Fe/Nd2O3 core-shell nanoparticles (CSNs) with a mean diameter of 35 nm were produced successfully by using hydrogen plasma-metal reaction (HPMR) method. This core-shell structure was confirmed by high resolution transmission electron microscopy (HRTEM), energy dispersion X-ray spectroscopy (EDS), X-ray photoelectron spectral (XPS), and induction-coupled plasma (ICP) spectroscopy. The magnetic properties were measured by vibrating sample magnetometer (VSM). It was found that the mole ratio of Nd to Fe on the nanoparticle surface is 1.2:1, about 7 times of that of the whole nanoparticle. The saturation magnetization Ms and remanence Mr of Fe/Nd2O3 nanoparticles decrease prominently from Fe nanoparticles, whereas the coercivity Hc drops only less than 5% of Fe nanoparticle. These CSNs have potential applications in magnetic and catalytic fields.     

碳纳米管承载纳米Fe_3O_4颗粒的制备(英文)

采用一种简单又经济的方法将Fe3O4纳米颗粒填充到碳纳米管中。透射电镜(TEM)、扫描电镜(SEM)及其能谱附件(EDX)和X射线多晶衍射(XRD)测试结果表明:Fe3O4纳米颗粒成功地填充到碳纳米管中。材料的磁性能测试结果表明:碳纳米管中填充Fe3O4纳米颗粒后,在常温下具有超顺磁性,其饱和磁化强度由0.35emu/g增大到了13.15emu/g。Fe3O4纳米颗粒填充的碳纳米管可望应用于工程和医学领域。     

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。     

Fabrication of triple-layered magnetite/hydrogel/quantum dots via the molecular linkage of bi-functional diamines

A multifunctional biomedical agent with magnetism, pH-sensitive, fluorescent properties was fabricated as a triple-layered magnetite/hydrogel/quantum dots. First, core-shell magnetic silica nanospheres (Fe3O4@SiO2) were synthesized via the sol-gel reaction of magnetite clusters with tetraethyl orthosilicate (TEOS), and the resuting magnetic particles were encapsulated with poly(N-isopropylacrylamide-co-acrylic acid) hydrogels through a free radical polymerization. The hydrogel-encapsulated magnetic particles were subsequently anchored by quantum dots (QDs) via the molecular linkage of bi-functional diamines. Diamine molecules effecrively induced the crosslinking between magnetic hydrogels and quantum dots. Among diamine linkers with different chain lengths (C-4, C-8, and C-12), C-8 diamine (1,8-diaminooctane) produced the maximal PL intensity for QD-bound hydrogels, indicating that C-8 diamine was an optimal cross-linker between hydrogels and QDs with surface carboxylic acid groups. The characteristic properties of the multifunctional nanocomposites were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), zeta-potential meter, and photoluminescence (PL) spectroscopy.