设计与制备基于链霉亲和素-生物素接合的铁蛋白-金纳米粒子二聚体

金纳米粒子二聚体在纳米科学技术的诸多领域中展示出引人注目的成就,但金纳米粒子二聚体的制备仍然是一项具有挑战性的工作。文章对基于链霉亲和素-生物素接合的铁蛋白-金纳米粒子二聚体的设计与制备进行了研究,通过混合生物素标记的突变型铁蛋白亚基和野生型铁蛋白亚基包覆金纳米粒子,用链霉亲和素将两个装载了金纳米粒子的铁蛋白连接,透射电子显微镜测试结果证实了上述设计方案的有效性。该方案可广泛应用于制备含有其他金属核的纳米粒子二聚体体系。     

金纳米粒子的制备及自组装

金纳米粒子以它独特的光学、电学和催化性质以及在纳米级电子线路中的应用潜力,受到人们越来越多的关注.本文主要评述了金纳米粒子的合成方法和自组装技术,即对各种制备方法和自组装的特点、纳米粒子的生长机理和自组装机理进行了介绍.展望了金纳米材料未来的研究方向和发展趋势.     

金纳米粒子的最新研究进展

金纳米粒子是最稳定的金属纳米粒子之一，由于其具有优良的稳定性和光学性质，使其在许多领域有着广阔的应用前景。本文主要对金纳米粒子和表面修饰金纳米粒子的制备方法进行分析总结，指出各种方法的制备原理及特点。同时，阐述了金纳米粒子的一些特殊性能，如：表面吸收带效应、荧光效应、量子尺寸效应、单电子跃迁等。并对金纳米粒子的应用进行了展望。     

羟基化SBS模板合成金纳米粒子及表征

以羟基化SBS为模板,N,N-二甲基甲酰胺(DMF)为溶剂,氯金酸为原料,硼氢化钠为还原剂,在一定反应条件下制备得到了金纳米粒子。采用紫外-可见光谱和透射电子显微镜等方法对所合成的纳米金样品进行了表征。结果表明,羟基化SBS可以为金纳米粒子的成核和长大起到较好的模板作用,金纳米粒子可以产生纳米金所具有的表面等离子态的特征吸收峰;改变合成条件,可以控制金纳米粒子特征吸收峰的位置;透射电子显微镜给出金纳米粒子具有球状形貌特征,且具有较窄尺寸分布。     

使用纳米焊接从金纳米粒子自下而上制备三维纳米多孔金（英文）

三维纳米多孔金具有高的比表面积、高的导电性和等离激元特性等众多优异的物理化学性质,可以应用于多个领域.然而,其最常见的制备方法,即脱合金,面临着高能耗、资源浪费、需使用腐蚀性液体和牺牲组分的残留等问题.本文中,我们报道了一种较普适性的自下而上的纳米焊接方法,用于从金纳米粒子制造高纯度三维纳米多孔金.该方法先将化学合成的金纳米粒子在液-液界面自组装成致密的单层金纳米粒子薄膜,随后将其逐层转移到固体基底上形成多层的金纳米粒子膜,最后对该多层金纳米粒子膜在空气中通直流电进行纳米焊接.研究结果表明,直流电纳米焊接工艺可在10 s内在低温下将层状金纳米颗粒薄膜逐渐转变为纳米多孔金,同时不会破坏母体金纳米粒子的球形结构.这是因为在纳米焊接过程中,电子更倾向于聚集在高电阻的粒子/粒子结点处,造成该处的表面原子受到较强的静电排斥作用,从而强化了该处的表面原子扩散并引发温和的固态扩散纳米焊接.此外,当使用不同尺寸的金纳米粒子作为起始构筑单元时,该方法可有效调整纳米多孔金的厚度、韧带尺寸和孔径,从而为构筑功能性多孔纳米材料(如用于甲醇电氧化的电催化剂)提供极大的灵活性.可以预料,该低温纳米焊接方法也可用于...     

不同形貌金纳米粒子的制备及其光谱特性

本文以柠檬酸三钠(Na3C6H5O7.2H2O)保护的小粒径金胶体为晶种,采用晶种法制备了不同形状的金纳米粒子。利用透射电子显微镜(TEM)和紫外可见光谱(UV-Vis)对所制备的金纳米粒子进行了表征。结果表明,随着晶种量的增加,金纳米粒子的形状依次为水滴状、梭状和球状,并且发现梭状金纳米粒子位于850nm处的多极共振吸收峰。基于表征结果分析了不同形貌产物的可能形成机理。     

纳米金粒子的理化性质、制备及修饰技术和应用研究现状及进展

概述了国内外近几年来纳米金粒子的研究新进展,并重点介绍了纳米金粒子的物理、化学、光学等特性,化学法与绿色环境法制备纳米金粒子以及各种分子修饰纳米金技术等,同时指出了纳米金粒子的实际应用情况以及今后的研究发展趋势。     

电纺丝技术制备金纳米粒子/聚合物复合纳米纤维的研究进展

静电纺丝技术是通过高压静电来制备连续的聚合物纳米纤维的重要方法.近年来,在电纺丝研究领域中,人们关注的焦点是利用此技术制备无机/有机纳米复合材料.金纳米粒子/高分子复合物由于具有独特的光、电性能引起了材料工作者的关注,综述了运用电纺丝技术制备金纳米粒子/高分子复合物的研究进展.     

不同形貌CuO纳米粒子的制备与性能

采用CuSO4.5H2O、Cu(NO3)2、(CH2)6N4和NaOH为原料,采用沉淀法分别制备纤维状CuO纳米粒子和纺锤状CuO纳米粒子,用透射电镜和X射线衍射仪对产物的大小﹑形貌和组成进行表征;按质量比为9∶1的比例将黑索金分别与纤维状CuO纳米粒子和纺锤状CuO纳米粒子混合,对样品进行热失重测试分析,根据黑索金热分解温度的变化来衡量催化剂的活性。结果表明,采用沉淀法制备CuO纳米粒子时,反应温度、终点pH值对产物形貌有显著影响;不同形貌的CuO纳米粒子对黑索金的分解催化作用效果不同。     

微乳法制备纳米金及其生物电催化性能研究

纳米金具有特殊的电催化性能。采用水/AOT(2-乙基己基琥珀酸酯磺酸钠)/环己烷微乳体系制备纳米金颗粒,通过改变水与AOT的物质的量比(ω)制备不同尺寸的纳米金,并通过透射电镜、紫外分光光度计、电化学工作站对纳米金颗粒的形貌尺寸、紫外吸收光谱、电化学性能进行分析与研究。结果表明,纳米金呈球形,尺寸均一,单分散性较好。通过对纳米金颗粒电催化析氢性能的测试发现,纳米金粒子分散性较好,形成的是均相溶液,纳米金粒子与Pt/C相比电催化性能稍弱,但是与纳米银、金铁合金和纳米硒化钨相比都显现出较好的电催化活性,说明纳米金粒子具有比较优良的电催化性能,为纳米金颗粒在生物电催化领域的应用奠定理论基础。     

A photochemical method for controlling the size of CdS nanoparticles

The optical and electrical properties of semiconductor nanoparticles are strongly dependent on their size. A flexible control of the size of the nanoparticles is of interest for tuning their properties for different applications. Here we use a coupled method to control the size of CdS nanoparticles. The method involves the photochemical growth of CdS nanoparticles together with the use of a capping agent as an inhibiting factor. CdS nanoparticles were formed through a photoinduced reaction of CdSO(4) and Na(2)S(2)O(3) in an aqueous solution. Mercaptoethanol (C(2)H(6)OS) was used as the capping agent, and we investigated the effect of illumination time, illumination intensity and the concentration of capping agent on the nanoparticle size. Transmission electron microscopy (TEM) shows crystalline nanoparticles with relatively low dispersion. Optical absorption spectroscopy was mainly used to measure the band gap and size of the nanoparticles. Increasing the illumination time or illumination intensity increases the nanoparticle size, while higher capping agent concentration leads to smaller nanoparticle size. A band gap range of 2.75-3.4?eV was possible with our experimental conditions, corresponding to a 3.2-6.0?nm size range.     

Size-dependent magnetic and dielectric properties of Tb-doped BiFeO3 nanoparticles

Pure and Tb-doped BiFeO₃ nanoparticles have been prepared by sol–gel method. The nanoparticles of different size have been obtained by the calcination of synthesized nanoparticles at different temperatures. The effects of Tb doping and size of nanoparticles on the crystal structure, magnetic and electrical properties have been studied. The partial substitution of Tb ions results in a change from rhombohedral (x = 0) to orthorhombic (x = 0.15) structure. The average crystallite size varies from 14 to 40 nm. The synthesized nanoparticles possess ferromagnetic behavior. The saturation magnetization is high for the Tb-doped BiFeO₃ nanoparticles calcined at 450 °C, and it decrease with the increase of size. The dielectric constant and loss improve with Tb doping and size. The relaxation behavior of dielectric loss is of Debye type. The dielectric loss peaks shift to the lower frequencies with increase in the size of Tb-doped BiFeO₃ nanoparticles.     

Liquid-Phase Preparation and Characterization of Zinc Oxide Nanoparticles

Zinc oxide (ZnO) nanoparticles have been prepared by a wet chemical method, from zinc acetate and LiOH ethanol-based solutions. The resulted nanoparticles were dispersed in a solvent. The effect of solvent (ethanol or butanol) and surfactant (polyethylene glycol-PEG 200) on the average size and size distribution of the nanoparticles was investigated by light scattering measurements. Smaller size was observed for ZnO nanoparticles dispersed in butanol and PEG 200. The statistical parameters of the Gaussian size distribution curves were calculated. ZnO nanoparticles have been prepared to be used as seeds on a substrate for the growth of ZnO nanowires. The morphology, surface roughness, crystalline structure, and orientation of the nanoparticles deposed on silicon substrate were characterized by atomic force microscopy and x-ray diffraction, respectively.     

Large scale synthesis and characterization of Ni nanoparticles by solution reduction method

Ni nanoparticles were mass synthesized by solution reduction process successfully. The influence of the parameters on the particle size of Ni nanoparticles were studied and the referential process parameters were obtained. The morphology and structure of the synthesized Ni nanoparticles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis and infrared spectroscopy (IR). The results show that Ni nanoparticles are of high purity and are covered by hydroxyethyl carboxymethyl cellulose (HECMC) layer and the mean size being about 31 nm. The magnetic measurement revealed that Ni nanoparticles are ferromagnetic.     

Effect of SH-containing ligands on the growth of CdS nanoparticles

Cadmium sulfide nanoparticles have been synthesized via precipitation from solution, using thioglycolic acid (TGA) and L-cysteine as stabilizing agents. The nanoparticle size has been evaluated using the absorption spectra of the solutions, dynamic light scattering data, and transmission electron microscopy. The L-cysteine-stabilized nanoparticles are smaller and more uniform in size compared to the TGA-stabilized nanoparticles. The effect of synthesis temperature on nanoparticle growth has been studied. With increasing synthesis temperature, the average radius of the nanoparticles increases, which is accompanied by their aggregation and broadening of their size distribution.     

Synthesis and characterization of CdTe quantum dots embedded gelatin nanoparticles via a two-step desolvation method

Novel CdTe quantum dots (QDs) embedded gelatin nanoparticles (CdTe/gelatin nanoparticles) were synthesized via a two-step desolvation method. The morphology and size distribution of the nanoparticles were characterized by transmission electron microscope (TEM) and laser particle size analyzer. They are presented spherically and relatively uniform with a diameter of 150 nm. The luminescent properties of the nanoparticles were investigated by using fluorescence spectrophotometry and fluorescence microscopy. The fluorescence stability of nanoparticles was tested in vitro. It was found that the nanoparticles were stable in water and phosphate-buffered saline (PBS) solution (pH 7.4) for at least 15 days. A possible formation mechanism of the CdTe/gelatin nanoparticles was also proposed. The inherent stability and biocompatibility indicate that the nanoparticles are expected to be promising candidates for in vivo biological imaging studies.     

自组装制备PEG接枝聚苯乙烯微球的粒径控制

用苯乙烯封端的聚乙二醇(St—PEG)大单体与苯乙烯(St)进行接枝共聚，将得到的双亲性接枝共聚物(PEG—g—PSt)逐步滴加到各种比例的甲醇／水的混合溶剂中，通过该聚合物在混合溶剂中的自组装，制得了PEG—g—PSt微球。用透射电子显微镜(TEM)和激光光散射(LLS)对微球的形态和粒径进行了表征。实验结果表明，改变接枝液组成、接枝液浓度、滴加速度以及混合溶剂组成等反应条件可有效地控制所得微球的粒径及其分布。     

Size- and shape-dependent melting enthalpy and entropy of nanoparticles

A theoretical model free of any adjustable parameter was derived based on the relation between Gibbs energy change and size to describe the size- and shape-dependent behavior of the melting enthalpy and entropy of nanoparticles. For the melting enthalpy and entropy of vanadium (V), silver (Ag), and copper (Cu) nanoparticles, the results of pure theoretical calculation are in good agreement with available molecular dynamic results. The effect of size on the melting enthalpy and entropy of nanoparticles is greater compared to that of shape effect. The melting enthalpy and entropy decrease with particle size decreasing and the smaller the particle size, the greater the size and shape effects. Furthermore, at the same equivalent diameter, the more the shape of nanoparticles deviates from that of the sphere, the smaller the melting enthalpy and entropy. The thermodynamic relations derived herein can quantitatively describe the influence regularities of size and shape on the melting thermodynamic properties of nanoparticles.     

Size-dependent structural and magnetic properties of chemically synthesized Co-Ni-Ga nanoparticles

Phase transitions and magnetic properties of shape-memory materials can be tailored by tuning the size of the constituent materials,such as nanoparticles.However,owing to the lack of suitable synthetic methods for size-controlled Heusler nanoparticles,there is no report on the size dependence of their properties and functionalities.In this contribution,we present the first chemical synthesis of size-selected Co-Ni-Ga Heusler nanoparticles.We also report the structure and magnetic properties of the biphasic Co-Ni-Ga nanoparticles with sizes in the range of 30-84 nm,prepared by a SBA-15 nanoporous silicatemplated approach.The particle sizes could be readily tuned by controlling the loading and concentration of the precursors.The fractions and crystallite sizes of each phase of the Co-Ni-Ga nanoparticles are closely related to their particle size.Enhanced magnetization and decreased coercivity are observed with increasing partide size.The Curie temperature (Tc) of the Co-Ni-Ga nanoparticles also depends on their size.The 84 nm-sized particles exhibit the highest Tc (≈ 1,174 K) among all known Heusler compounds.The very high Curie temperatures of the Co-Ni-Ga nanoparticles render them promising candidates for application in high-temperature shape memory alloy-based devices.     

Influence of anions on the formation and properties of chitosan-DNA nanoparticles

Chitosan-DNA nanoparticles were prepared by using different anions (such as chloride, sulfate, citrate, and tripolyphosphate) as mediation agents. The research suggested that the formation and morphological characteristics of chitosan-DNA nanoparticles largely depended on concentration, molecular size, charge number, and chemical structure of anions, as well as chitosan/DNA ratio. The observation by atom force microscopy showed that chitosan-DNA nanoparticles mediated by four anions (in their appropriate range of concentration) had a spherical shape, narrow size distribution, and good monodispersivity. Especially, nanoparticles mediated by sulfate and TPP had a size distribution of 40-50 nm. Additionally, the nanoparticles presented high encapsulation efficiency and good protection of DNA from DNasel digestion. The zeta-potential of nanoparticles could be adjusted moderately by adding different anions and controlling their concentrations, and DNA encapsulation efficiency was not influenced, which would reduce nonspecific interactions with the cell membrane and nanoparticle toxicity. Smaller size and lower zeta-potential will be beneficial for improving gene therapy. In addition, the anion mediation method has potential for the preparation of cationic polymer nanoparticles as drug or gene vectors.