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1.
Monodispersed FePt nanoparticles with hydrophobic ligand were chemically synthesized and with controllable surface-functional properties. In order to enhance the saturation magnetization of FePt nanoparticles, the initial mole ratio of Fe to Pt precursors and reaction times were controlled to effectively increase magnetization due to the increased particle size and formation of FePt-Fe3O4 nanocomposites. The surface modification of FePt nanoparticles by using mercaptoacetic acid (C2H4O2S) as a phase transfer reagent through ligand exchange turned the nanoparticles hydrophilic, and the nanoparticles could water-dispersible. The streptavidin-biotin binding pair was used to conjugate with carboxylic acid (COOH) functional group on the surface of FePt nanoparticles that could be further functionalized to provide a biotin moiety for specific interactions with streptavidin protein. 相似文献
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A novel nanoscale catalyst system composed of nanosized Pd catalysts immobilized on Fe(3)O(4)@SiO(2)-PAMAM 总被引:1,自引:0,他引:1
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. 相似文献
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Fe(3)O(4)@SiO(2) core-shell structure nanoparticles were first prepared and characterized by TEM, FTIR, XPS and XRD. Subsequently the widely used anticancer agent doxorubincin (DOX) was successfully grafted to the surface of the core-shell nanoparticles via an amide bond with the aid of a spacer arm we synthesized. The spacer arm met two needs: one end can couple to the core-shell nanoparticles' surface while the other end was the active?-COOH group, which can react with the?-NH(2) group of DOX molecules. The synthesized spacer arm and the conjugation of the drug with nanoparticles through amidation were confirmed by FTIR. The DOX-loading efficiency determined by UV-vis spectrometer was 86.5%. Drug release experiments displayed a pH-dependent behavior that DOX was cleaved from the nanoparticles easily under low pH conditions in the presence of protease and that most of the conjugated doxorubincin were released within the first 12?h. The prepared DOX-grafted Fe(3)O(4)@SiO(2) core-shell structure nanoparticles showed a superparamagnetic property with a saturation magnetization value of 49.3?emu?g(-1), indicating a great potential application in the treatment of cancer using magnetic targeting drug-delivery technology. 相似文献
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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。 相似文献
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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. 相似文献
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Park SI Kwon BJ Park JH Jung H Yu KH 《Journal of nanoscience and nanotechnology》2011,11(2):1818-1821
In this study, we have successfully developed 3-[131I]iodo-tyrosine grafted Fe3O4@SiO2 nanocomposites for dual potential tumor imaging agent for SPECT and MRI. Fe3O4 nanoparticle was synthesized through thermal decomposition and Fe3O4@SiO2 was prepared by reverse microemulsion method. After conjugating aminopropyltriethoxysiliane, L-tyrosine was introduced by amide coupling reaction. Finally, [131I]iodide was labeled on L-tyrosine grafted Fe3O4@SiO2 nanocomposite by aromatic iodination using chloramine-T. 相似文献
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Dong YL Zhang HJ Yan N Zhou L Zhang ZY Rahman ZU Chen XG 《Journal of nanoscience and nanotechnology》2011,11(12):10387-10395
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. 相似文献
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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. 相似文献
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以丙烯酰胺为单体,采用原位聚合法制备了Fe3O4/聚丙烯酰胺纳米磁粒(Fe3O4/PAM);利用胺基与金的相互作用,借助自组装法在Fe3O4/PAM表面组装金胶体制备了草莓型纳米金磁颗粒(Fe3O4/PAM/Au);用TEM、VSM、UV-vis对其进行了表征,并考察了表面修饰核酸探针的金磁颗粒对核酸靶分子的分离能力。结果表明,Fe3O4/PAM/Au粒子的粒径为36~56nm,具有超顺磁性,饱和磁化强度为31.2emu/g,分散在磷酸盐缓冲液中的Fe3O4/PAM/Au完全磁分离的时间为6min。修饰核酸探针的Fe3O4/PAM/Au粒子可以借助核酸杂交作用分离核酸靶分子,分离能力为118pmol/mg。 相似文献
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Magnetite nanoparticles coated by mesoporous silica were synthesized by an alternative chemical route using a neutral surfactant and without the application of any functionalization method. The magnetite (Fe(3)O(4)) nanoparticles were prepared by precipitation from aqueous media, and then coated with mesoporous silica by using nonionic block copolymer surfactants as the structure-directing agents. The mesoporous SiO(2)-coated Fe(3)O(4) samples were characterized by x-ray diffraction, Fourier-transform infrared spectroscopy, N(2) adsorption-desorption isotherms, transmission electron microscopy, (57)Fe M?ssbauer spectroscopy, and vibrating sample magnetometry. Our results revealed that the magnetite nanoparticles are completely coated by well-ordered mesoporous silica with free pores and stable (~8?nm thick) pore walls, and that the structural and magnetic properties of the Fe(3)O(4) nanoparticles are preserved in the applied synthesis route. 相似文献
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In this study, we report the chemical synthesis and functionalization of streptavidin coated gold magnetic nanoparticles (GMNPs) and the immobilization of single-stranded biotinylated oligonucleotides onto these particles. By using covalent interaction or physical adsorption, two kinds of streptavidin coated GMNPs (SA-GMNPs) were prepared. The quantity and stability of streptavidin bound to the GMNPs using different methods were determined by UV-Vis spectrometer. The results indicated that by physical absorption the GMNPs can capture more streptavidin, the SA-GMNPs with either physical adsorption or covalent reaction were both stable in PBS buffer. In contrast, SA-GMNPs with covalent reaction was stable in SDS buffer, while most of the SA-GMNPs by physical adsorption would be eluted from the particles in SDS buffer. Therefore, the SA-GMNPs by covalent immobilization were more suitable for fabrication of bead array. To evaluate the binding efficiency and capacity of DNA on SA-GMNPs, the capture of biotinylated oligonucleotide or PCR products on SA-GMNPs at different concentrations were examined. A magnetic beads array was fabricated by immobilizing DNA-MNPs complexes onto a glass slide using a magnetic field. The synthesized DNA targets with different concentrations were detected with a detection limit of approximately 0.05 nM, indicating the potential application of this MNPs array to high-throughput DNA detection. 相似文献
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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... 相似文献
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A novel cell separation and immobilization method for Cr (VI)-reduction under alkaline conditions was developed by using superparamagnetic Fe(3)O(4) nanoparticles (NPs). The Fe(3)O(4) NPs were synthesized by coprecipitation followed by modification with sodium citrate and polyethyleneimine (PEI). The surface-modified NPs were monodispersed and the particle size was about 15 nm with a saturation magnetization of 62.3 emu/g and an isoelectric point (pI) of 11.5 at room temperature. PEI-modified Fe(3)O(4) NPs possess positive zeta potential at pH below 11.5, presumable because of the high density of amine groups in the long chains of PEI molecules on the surface. At initial pH 9.0, Pannonibacter phragmitetus LSSE-09 cells were immobilized by PEI-modified NPs via electrostatic attraction and then separated with an external magnetic field. Compared to free cells, the coated cells not only had the same Cr (VI)-reduction activity but could also be easily separated from reaction mixtures by magnetic force. In addition, the magnetically immobilized cells retained high specific Cr (VI)-reduction activity over six batch cycles. The results suggest that the magnetic cell separation technology has potential application for Cr (VI) detoxification in alkaline wastewater. 相似文献
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纳米Fe3O4颗粒及磁性液体的制备 总被引:10,自引:0,他引:10
用低温相转化法制备了小粒径的Fe3O4纳米颗粒,用油酸对纳米颗粒进行了表面处理,溶液pH为6.90,80℃下恒温反应50~60min时磁性粉体颗粒的改性效果较好。然后将包覆颗粒分散到载液中制得磁性液体。实验中用XRD、TEM、VSM、IR光谱等对所制的样品进行了相应表征,并将UV光谱分析方法用于油酸包覆的定量评估,从而建立了磁性颗粒表面修饰的表征方法。 相似文献
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首先通过水热法合成了单分散空心Fe3O4磁球,之后利用蒸馏沉淀聚合将P(GMA-DVB)聚合物层包覆在Fe3O4磁球表面形成Fe3O4/P(GMA-DVB)核壳结构,巯基化处理后吸附Au纳米粒子,得到磁性核壳Fe3O4/P(GMA-DVB)-SH-Au复合催化剂。利用TEM,SEM,FTIR,XRD,TGA,VSM及UV-vis对其进行表征,并考察该催化剂在催化还原4-硝基苯酚反应中的催化性能。结果表明合成的材料粒径均匀,球形度规整,核壳结构明显,在催化反应中,Fe3O4/P(GMA-DVB)-SH-Au表现出优异的催化性能,而且经过连续8次循环使用后,催化效率仍可保持80%以上。 相似文献
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Zhou J Zhang R Li X Gutmann S Lv G Wang X 《Journal of nanoscience and nanotechnology》2007,7(8):2942-2947
Fe3O4 nanoparticles are the most commonly used magnetic materials with promising applications in biomedical and biochemical engineering. In this study, a novel application of the tetraheptylammonium capped Fe3O4 nanoparticles in controllable biorecognition process of anticancer drug doxorubicin through combination with external static magnetic field has been demonstrated. Our AFM and electrochemical studies illustrate that the presence of the tetraheptylammonium capped Fe3O4 nanoparticles could promote the binding behavior of doxorubicin to DNA. And the results of the electrochemical contact angle measurements indicate that the controllable biomolecular recognition of doxorubicin could be readily achieved by combining these functionalized Fe3O4 nanoparticles with changing the positions of external magnetic field. 相似文献