磁性纳米复合氧化物固体酸催化剂的制备及酯化性能

固体酸催化剂的无腐蚀、环境友好和可循环使用等特点使其成为无机液体酸的最佳替代物.磁性纳米固体酸具有优于常规固体酸催化剂的催化活性及分离简单的特性.用共沉淀法分别合成了一系列三组分TiO2-Al2O3-Fe3O4(TAF)和CeO2-Al2O3-Fe3O4(CAF)及四组分ZrO2--Al2O3-Fe3O4(ZACF)磁性纳米复合氧化物固体酸催化剂,通过电感耦合等离子体原子发射光谱、比表面积测定、X射线衍射、透射电镜、热重分析和红外光谱等对其进行了表征,并利用酯化反应作为探针反应评价了其催化性能.结果表明,合成的磁性纳米固体酸催化剂在酯化反应中表现出很好的催化活性.     

β-环糊精-Fe_3O_4超分子体系的构筑及其应用研究进展

详细综述了目前β-环糊精-Fe3O4超分子体系的构筑及其应用进展,主要包括以共价键键连的β-环糊精-Fe3O4超分子体系在环境污染物吸附、药物分子负载和缓释、传感检测、分离和催化领域中的应用.上述各部分中,根据β-环糊精与Fe3O4纳米粒子之间连接基团的不同,对各类β-环糊精-Fe3O4超分子体系的构筑及其性能进行了系统介绍.指出β-环糊精-Fe3O4超分子体系兼具β-环糊精的包结吸附性能、弱催化性能及底物识别性能和Fe3O4组分的磁性载体作用,易于回收;β-环糊精固载在Fe3O4纳米粒子上,构筑非均相β-环糊精-Fe3O4超分子仿生催化体系,是今后构筑纳米级超分子仿生催化剂的研究热点之一.     

基于二氧化硅荧光纳米颗粒与核酸染料SYBRGreenⅠ的双色显微成像技术用于E.coliO157:H7的检测

将免疫荧光纳米标记技术与激光共聚焦显微成像方法相结合,发展了一种基于二氧化硅荧光纳米颗粒和核酸染料SYBR Green Ⅰ的双色显微成像技术用于大肠杆菌O157:H7的检测.采用联吡啶钌(RuBpy)二氧化硅荧光纳米颗粒对羊抗大肠杆菌O157:H7抗体进行修饰,基于抗体-抗原相互作用实现了其对目标大肠杆菌O157:H7的特异性标记;同时以核酸染料SYBR Green Ⅰ对细菌进行染色,将细菌和纳米颗粒团聚体区分开,实现了对大肠杆菌O157:H7的双色标记,并通过激光共聚焦显微镜进行免分离的荧光成像检测.结果表明,该方法可用于缓冲溶液体系和混合细菌样品中目标大肠杆菌O157:H7的特异性检测,在仅含5％目标菌的混合样品中仍能观察到具有明显黄色荧光的大肠杆菌O157:H7,且整个检测步骤包括样品预处理可在3h内完成.该方法则具有较好的灵敏度,可检出2.6×103 Cell/mL的目标细菌样品.若采用针对其它病原菌细胞壁抗原的特异性抗体,则有望发展成为一种通用技术用于多种病原菌的快速和灵敏检测.     

荧光二氧化硅纳米颗粒的制备、修饰及细胞成像分析

在微乳液体系中合成荧光二氧化硅纳米颗粒(FSNPs),然后对其表面进行氨基修饰,之后再连接抗体,应用高分辨透射电镜(HR-TEM),原子力显微镜(AFM),Zeta-电位分析仪,IR,荧光显微镜及激光共聚焦显微镜等多种表征工具对合成的颗粒和后续的修饰进行了系统分析.研究表明,FSNPs在溶液中呈现单分散状态,但是在表面...     

Fe3O4@YF3:Eu3+双功能复合颗粒的制备与性能研究

采用直接沉淀法合成了Fe3 O4@ YF3:Eu3核壳结构磁性-荧光性双功能纳米复合颗粒,对其结构和性能进行了表征.XRD分析表明,得到了结晶良好的尖晶石型Fe3 O4纳米晶和正交相的YF3纳米晶.TEM照片表明,双功能复合颗粒具有明显的核壳结构.构成核的Fe3 O4纳米颗粒尺寸在40 ～80nm之间.Fe3 O4@ YF3:Eu3+核壳结构复合纳米颗粒的尺寸约为100 ～250 nm,壳层YF3:Eu3+厚度介于20 ～30 nm之间.EDS分析表明样品由Y,F,Eu,O和Fe元素组成.荧光光谱和磁性测试结果表明,复合颗粒同时具有良好的发光性和较强的磁性,使其在生物医学领域具有潜在的应用.     

一步水热法合成三种形貌纳米α-Fe2O3的机理及磁性能研究（摘要）

纳米α-Fe2O3以其优良的生物相容性、环境友好性、稳定性、催化性、以及磁性被广泛的应用于生物医学、颜料、催化、传感以及半导体等领域.为了实现不同形貌纳米α-Fe2O3的工业化可控合成,我们采用一步水热法,通过控制体系的反应时间,依次制备出了纺锤体状、管状和轮胎状的α-Fe2O3纳米结构,并利用X射线衍射仪、扫描电子显微镜和透射电子显微镜对产物进行了表征.体系中磷酸根离子在α-Fe2O3晶面上的特异性吸附是主导α-Fe2O3形貌演进的关键性因素.其作用主要体现在两个方面：一是使α-Fe2O3颗粒产生各向异性生长,形成纳米纺锤体;二是阻止某些晶面参与质子轰击反应,形成α-Fe2O3纳米管,进而促进体系中Fe4（PO4）3（OH）3相的形成与α-Fe2O3相的再结晶,最终形成轮胎状纳米结构.通过超导量子干涉仪对产物的磁性能表征,发现产物的不同形貌以及形状各项异性会对矫顽力、磁化强度以及低温磁性相变温度等磁学参量产生显著的影响.     

高稳定性荧光纳米SiO2的合成及其在磷脂巨型囊泡成像中的应用

在不同类型醇溶剂中,通过改进St?ber法合成了三种不同粒径的荧光纳米SiO2颗粒,并将其应用于磷脂巨型囊泡的成像.荧光光谱法检测数据显示,荧光纳米颗粒的粒径大小对荧光强度影响巨大,纳米颗粒粒径越小的荧光强度及存储稳定性越强;激光共聚焦显微镜检测结果及光漂白实验证实,所合成的荧光纳米SiO2颗粒具有较佳的荧光稳定性.荧...     

NaYF_4:Yb/Er-碳纳米管功能纳米材料的制备、表征及其在肿瘤细胞的靶向检测和治疗中的应用

将叶酸分子(FA)和2,3-二巯基丁二酸(DMSA)修饰的稀土上转换发光纳米粒子NaYF4:Yb/Er通过酰胺键偶联在多壁碳纳米管(MWCNT)的表面,得到NaYF4:Yb/Er-MWCNT-FA功能化复合纳米材料,并通过透射电子显微镜(TEM)、X射线衍射(XRD)、紫外-可见吸收光谱(UV-vis)、荧光光谱(PL)和共聚焦激光扫描显微镜等手段表征了其形貌、结构、发光性能和靶向成像性能.共聚焦激光扫描显微镜结果表明,相对于正常的HLF细胞,所制备的复合材料能够靶向检测叶酸受体高表达的宫颈癌Hela细胞.此外,将阿霉素进一步通过ππ堆垛吸附在此复合材料后,该载药体系具有明显的抗肿瘤活性,能够实现对肿瘤细胞的一步检测和治疗.     

基于二氧化硅荧光纳米颗粒与核酸染料SYBRGreenⅠ的双色显微成像技术用于E.coliO157:H7的检测

将免疫荧光纳米标记技术与激光共聚焦显微成像方法相结合,发展了一种基于二氧化硅荧光纳米颗粒和核酸染料SYBR Green Ⅰ的双色显微成像技术用于大肠杆菌O157:H7的检测.采用联吡啶钌(RuBpy)二氧化硅荧光纳米颗粒对羊抗大肠杆菌O157:H7抗体进行修饰,基于抗体-抗原相互作用实现了其对目标大肠杆菌O157:H7...     

荧光/MRI双模态靶向成像诊疗试剂的制备

在聚乙二醇二胺(NH_2-PEG-NH_2)修饰的石墨烯量子点(GODs)表面以酰胺键偶联二乙基三胺五乙酸(DTPA)分子,之后将Gd~(3+)离子与其进行配合,得到了GODs-Gd(DTPA)复合纳米粒子,然后再通过酰胺键在GODs-Gd(DTPA)的表面修饰叶酸(FA)靶分子,最后进一步将阿霉素(DOX)通过π-π堆垛吸附在造影剂的表面,制备了FA/GODs-Gd(DTPA)/DOX荧光/MRI双模态靶向肺癌细胞成像诊疗试剂,通过透射电子显微镜、紫外可见吸收光谱、荧光光谱和激光共聚焦扫描显微镜等手段表征了其形貌、发光性能和靶向成像性能。MRI、激光共聚焦扫描显微镜和MTT等结果表明,相对于正常的HLF细胞,所制备的FA/GODs-Gd(DTPA)/DOX纳米粒子能够靶向检测FA受体高表达的肺癌H460细胞,并具有明显的抗肿瘤活性。     

Dual-targeted nanoformulation with Janus structure for synergistic enhancement of sonodynamic therapy and chemotherapy

The accurate delivery of nanoparticles and organic small molecule drugs remains a serious challenge in nanoparticle-based tumor therapy. Dual-targeted therapy combining tumor cell targeting and organelle targeting is an effective solution. Here, an anticancer nanoformulation accurate delivery system was prepared using hyaluronic acid (HA) targeting CD44 receptors on the surface of tumor cells and IR780 iodine (IR780) targeting mitochondrial for delivery. The system is based on an ultra-small Janus structured inorganic sensitizer TiO_2-x@NaGdF₄ nanoparticles (TN NPs) prepared by one-step pyrolysis, further loaded with organic small molecule acoustic sensitizer IR780 and mitochondrial hexokinase II inhibitor lonidamine (LND), followed by encapsulation of HA. Ultra-small size nanoparticles exhibit strong tissue penetration, tumor inhibition and in vivo metabolism. Under ultrasound radiation, TN NPs and IR780 could produce a synergistic effect, effectively increased the efficiency of reactive oxygen species (ROS) production. Meanwhile, the released IR780 could smoothly target the mitochondria, and the ROS produced by IR780 can destroy the mitochondrial structure and disrupt the mitochondrial respiration. LND could inhibit the energy metabolism of tumor cells by reducing the activity of hexokinase II (HK II), which further accelerates the process of apoptosis. Furthermore, since the Janus structure allows the integration of multifunctional components into a single system, TN NPs can not only serve as an acoustic sensitizer to generate ROS, but the Gd element contained can also act as the nuclear magnetic resonance (MR) imaging contrast agent, suggesting that the nanoformulation can enable imaging-guided diagnosis and therapy. In conclusion, a new scheme to enhance sonodynamic therapy (SDT) and chemotherapy synergistically is proposed here based on ultra-small dual-targeted nanoformulation with Janus structure in the ultrasound radiation environment.     

Novel nanocomposite of nano fe(3)o(4) and polylactide nanofibers for application in drug uptake and induction of cell death of leukemia cancer cells

Novel nanocomposites of polylactide (PLA) nanofibers and tetraheptylammonium-capped Fe3O4 magnetic nanoparticles have been prepared and utilized to realize the efficient accumulation of anticancer drug daunorubicin in target cancer cells. The observations of optical microscopy and confocal fluorescence microscopy indicate that the PLA nanofibers and Fe3O4 nanoparticles may contribute to their beneficial effects on intracellular drug uptake of leukemia K562 cell lines in which the efficiently enhanced accumulation of anticancer drug daunorubicin on the membrane of cancer cells could be observed. Meanwhile, the electrochemical detection and the microculture tetrazolium studies were also explored to probe the effect of the relevant nanomaterials on the drug uptake of cancer cells. The results illustrate that the nanocomposites could effectively facilitate the interaction of daunorubicin with leukemia cells and remarkably enhance the permeation and drug uptake of anticancer agents in the cancer cells, which could readily lead to the induction of the cell death of leukemia cells. This observation suggests a new perspective for the targeted therapeutic approaches of cancers.     

Microchip-based immunomagnetic detection of circulating tumor cells

Screening for circulating tumor cells (CTCs) in blood has been an object of interest for evidence of progressive disease, status of disease activity, recognition of clonal evolution of molecular changes and for possible early diagnosis of cancer. We describe a new method of microchip-based immunomagnetic CTC detection, in which the benefits of both immunomagnetic assay and the microfluidic device are combined. As the blood sample flows through the microchannel closely above arrayed magnets, cancer cells labeled with magnetic nanoparticles are separated from blood flow and deposited at the bottom wall of the glass coverslip, which allows direct observation of captured cells with a fluorescence microscope. A polydimethylsiloxane (PDMS)-based microchannel fixed on a glass coverslip was used to screen blood samples. The thin, flat dimensions of the microchannel, combined with the sharp magnetic field gradient in the vicinity of arrayed magnets with alternate polarities, lead to an effective capture of labeled cells. Compared to the commercially available CellSearch? system, fewer (25%) magnetic particles are required to achieve a comparable capture rate, while the screening speed (at an optimal blood flow rate of 10 mL h(-1)) is more than five times faster than those reported previously with a microchannel-based assay. For the screening experiment, blood drawn from healthy subjects into CellSave? tubes was spiked with cultured cancer cell lines of COLO205 and SKBR3. The blood was then kept at room temperature for 48 hours before the screening, emulating the actual clinical cases of blood screening. Customized Fe(3)O(4) magnetic nanoparticles (Veridex Ferrofluid?) conjugated to anti-epithelial cell adhesion molecule (EpCAM) antibodies were introduced into the blood samples to label cancer cells, and the blood was then run through the microchip device to capture the labelled cells. After capture, the cells were stained with fluorescent labelled anti-cytokeratin, DAPI and anti-CD45. Subsequent immunofluorescence images were taken for the captured cells, followed by comprehensive computer aided analysis based on fluorescence intensities and cell morphology. Rare cancer cells (from ～1000 cells down to ～5 cells per mL) with very low tumor cell to blood cell ratios (about 1?:?10(7) to 10(9), including red blood cells) were successfully detected. Cancer cell capture rates of 90% and 86% were demonstrated for COLO205 and SKBR3 cells, respectively.     

Three-layer composite magnetic nanoparticle probes for DNA

A method for synthesizing composite nanoparticles with a gold shell, an Fe3O4 inner shell, and a silica core has been developed. The approach utilizes positively charged amino-modified SiO2 particles as templates for the assembly of negatively charged 15 nm superparamagnetic water-soluble Fe3O4 nanoparticles. The SiO2-Fe3O4 particles electrostatically attract 1-3 nm Au nanoparticle seeds that act in a subsequent step as nucleation sites for the formation of a continuous gold shell around the SiO2-Fe3O4 particles upon HAuCl4 reduction. The three-layer magnetic nanoparticles, when functionalized with oligonucleotides, exhibit the surface chemistry, optical properties, and cooperative DNA binding properties of gold nanoparticle probes, but the magnetic properties of the Fe3O4 inner shell.     

Fe3O4-LiMo3Se3 nanoparticle clusters as superparamagnetic nanocompasses

A scaleable chemical approach to functional nanoscale analogues of the magnetic compasses in magnetotactic bacteria is described. LiMo(3)Se(3)-Fe(3)O(4) nanowire-nanoparticle composites were synthesized by a reaction of 3-iodopropionic acid treated LiMo(3)Se(3) nanowire bundles with oleic acid-stabilized Fe(3)O(4) nanoparticles of 2.8, 5.3, and 12.5 nm size in tetrahydrofuran. Transmission electron micrographs show that the composite consists of Fe(3)O(4) nanoparticles attached to the surfaces of the 4-6 nm thick nanowire bundles. UV/vis spectra reveal absorptions from the nanowire (506 nm) and magnetite components (280-450 nm), and IR spectra show characteristic bands for the propionic acid linkers and for the residual oleic acid ligands on the magnetite particles. In the presence of excess oleic acid, the nanocomposites undergo rapid disassembly, suggesting that Fe(3)O(4) nanoparticles are bonded to nanowires via carboxylate groups from the linkers. Ultrasonication of a dispersion of the composite in THF produces individual LiMo(3)Se(3)-Fe(3)O(4) clusters, which are 340 +/- 107 nm long and 20 +/- 5 nm thick, depending on the sonication time and Fe(3)O(4) nanoparticle size. Field cooled and zero-field cooled magnetization measurements reveal that the blocking temperature (T(B) = 100 K) of the clusters with 5.3 nm Fe(3)O(4) is increased as compared to the free nanoparticles (T(B) = 30 K). Directional dipolar interactions in the clusters lead to magnetic anisotropy, which makes it possible to align the clusters in a magnetic field (900 Oe).     

A magnetic MoS2-Fe3O4 nanocomposite as an effective adsorbent for dispersive solid-phase microextraction of lead(II) and copper(II) prior to their determination by FAAS

Microchimica Acta - The authors describe the preparation of a nanocomposite (mag-MoS2-Fe3O4) that was prepared from molybdenum disulfide (MoS2) and magnetic Fe3O4 nanoparticles by a hydrothermal...     

The design of hybrid materials based on magnetic Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles and luminescent CdS nanoparticles for cell visualization

Hybrid nanoparticles based on Fe₃O₄ and CdS combining magnetic and luminescence properties were synthesized. The possibility of visualization of various cells by 3-mercaptopropylsilane-modified CdS nanoparticles and hybrid nanoparticles based on them using a confocal microscope was demonstrated. The synthesized materials did not show a clear-cut cytotoxicity.     

Intracellular spatial control of fluorescent magnetic nanoparticles

We report a facile intracellular manipulation of fluorescent magnetic Fe3O4-CdSe nanoparticles using magnetic force. The growth of CdSe quantum dots on Fe3O4 nanoparticles produces Fe3O4-CdSe nanoparticles with two distinct properties, fluorescence and superparamagnetism. After nonspecific surface modification using glutathione (GSH), the hydrophilic Fe3O4-CdSe@GSH nanoparticles can be easily uptaken by an HEK293T cell line. Confocal images indicate that the uptaken nanoparticles can be manipulated using a small magnet. The successful intracellular manipulation of magnetic nanoparticles may offer a new strategy for studying polarized cells.     

Synthesis of polymer-supported Fe3O4 nanoparticles and their application as a novel route for the synthesis of imidazole derivatives

Research on Chemical Intermediates - Cross-linked poly(4-vinylpyridine) supported Fe3O4 nanoparticles, abbreviated as [P4-VP]-Fe3O4NPs, were easily prepared as a new magnetic polymeric catalyst and...     

Convenient Approach to °-Fe2O3 Nanoparticles: Magnetic and Electrochemical Properties

A convenient approach is reported for the synthesis of spherical maghemite (°-Fe2O3) nanoparticles. The process was realized by the controlled oxidation of Fe3O4 precursor, which originated from a facile partialreduction co-precipitation process. The starting material of hydrosulfurous sodium (Na2S2O4), which can allow reaction to proceed without any deoxygenated protection, was proven to be important in the formation of the precursor. A series of techniques, including X-ray diffraction, transmission electron microscopy and a vibrating sample magnetometer were used to characterize the product. The resultant °-Fe2O3 nanoparticles exhibited ferromagnetism at 300 K and the values of saturation magnetization and coercivity were 70 emu/g and 164 Oe, respectively. The electrochemical properties of lithium ions intercalation into °-Fe2O3 nanoparticles were tested in Te°on cells. A specific capacity of 933 mAh/g was delivered at a current density of 0.2 mA/cm2 (voltage range 3.0-0.3 V vs. Li), corresponding to the reaction of 5.7 Li+ per Fe2O3. A possible mechanism of the reaction of lithium with maghemite spinel was discussed.