石英纳米通道单磷脂囊泡的电阻-脉冲分析方法（英文）

本文报告了用于检测单囊泡及其粒径分析的石英纳米通道电阻-脉冲分析方法.采用圆柱形石英纳米通道可检测粒径为100~300 nm的单磷脂囊泡和直径为170~400 nm的聚苯乙烯纳米颗粒.单囊泡和纳米颗粒的迁移可通过检测各自产生的方波电流脉冲信号,并由此确定颗粒尺寸.结果表明,采用石英纳米通道电阻-脉冲分析方法得到的颗粒/囊泡粒径与采用动态光散射法和扫描电子显微法得到的结果完全一致.这种基于电子的分析方法具有快速简单的特点,所用的自制微传感器廉价耐用.石英通道的应用还可与其它分析方法如电流分析法和荧光显微法联用,以获得生物囊泡及人工囊泡更完全的信息.     

纳米ATO颗粒粒度分布的脉冲超声波测量研究

讨论了脉冲超声波测量纳米ATO颗粒粒度分布方法中的3个步骤,即超声波衰减谱测量、严格数学模型的选型以及颗粒粒度分布的反演计算.通过发射脉冲超声波并利用变声程方法测量25 ℃时2%(体积分数)的纳米ATO-H2O分散液的超声衰减谱;选取McClements理论模型叠加BLBL理论模型共同描述纳米ATO颗粒分散液中的超声衰减现象;采用最优正则优化反演算法反演得到纳米ATO颗粒的粒度分布以及平均粒径.脉冲超声法检测结果显示,纳米ATO颗粒的平均粒径为25.6 nm,粒度分布为11.4 ～47.1 nm,CPS离心沉降纳米粒度分析仪测定结果分别为22.1 nm和10.1 ～62.6 nm.脉冲超声法检测结果与透射电镜图像以及离心沉降纳米粒度分析仪检测结果吻合较好,证明了脉冲超声波测量纳米颗粒粒度分布以及平均粒径的可行性与可靠性.     

贵金属纳米颗粒杂化囊泡的制备及拉曼增强效果研究

以超支化聚合物囊泡为模板制备了贵金属纳米颗粒表面功能化的杂化囊泡.模板囊泡通过多巴胺修饰的超支化聚醚HSP-DA在水中自组装形成.在碱性条件下,囊泡表面的多巴胺自聚合生成聚多巴胺,实现囊泡的交联.由于聚多巴胺具有强黏附特性,因此可以将HSP-PDA交联囊泡分别与Au纳米溶胶、Ag纳米溶胶直接混合,得到Au纳米颗粒或Ag纳米颗粒功能化的杂化囊泡.分别测定了2种杂化囊泡的拉曼光谱,发现杂化囊泡产生了明显的表面增强的拉曼光谱(SERS)信号,清晰显示了对应于囊泡模板分子的拉曼信号,表明可以通过SERS来原位检测囊泡的组成.Ag纳米颗粒杂化囊泡展示出更高的SERS灵敏度,可进一步作为探针检测水中浓度为10-7mol/L罗丹明6G分子,得到了显著增强的拉曼光谱,证明所制备的Ag纳米颗粒杂化囊泡可用于目标分子的痕量检测.     

单颗粒-电感耦合等离子体质谱测定金纳米颗粒

单颗粒-电感耦合等离子体质谱法(Single particle-inductively coupled plasma-mass spectrometry,SPICP-MS)是近年出现的一种纳米材料分析方法,可用于表征纳米材料的元素组成、粒径分布以及颗粒物浓度。本研究对比了驻留时间(Dwell time,t_d)和稳定时间(Settling time,t_s)等质谱参数对单颗粒分析结果的影响,分析了金纳米颗粒标准物质(NIST 8012,NIST 8013,GBWE 120127)。结果表明,使用短的驻留时间(0.05 ms)和稳定时间(0 ms),可以获得更高的信噪比,检测到更多的纳米颗粒。利用本方法分析了AuNP标准物质,得到的粒径结果与标准值相符。本方法对金纳米颗粒的数量检出限为1.1×10~5L~(-1),粒径检出限为8 nm。     

单颗粒电化学分析

颗粒因其在基础研究和实际应用中均具有重要的价值,因而得到了广泛的关注.由于颗粒的功能和性质与其形貌、尺寸、电荷密度和表面化学性质等密切相关,因此,发展可用于单个颗粒(简称单颗粒)检测和分析的方法对于了解颗粒结构与性能的关系,进而研究其功能将具有重要的意义.单颗粒电化学(electrochemic alanalysis of single nanoparticle)检测技术是在最近几年发展起来的,由于其可以精确地探测单个纳米颗粒的性质(如表面电荷、几何尺寸、表面化学),因而展现出了诱人的应用前景.本文将对最近发展起来的单颗粒电化学检测方法进行详细介绍,并根据检测原理将单颗粒电化学检测分为3类:基于碰撞原理的微电极技术、基于电阻-脉冲原理的纳米通道技术以及基于电化学和其他方法的联用技术.基于此分类,重点综述单颗粒电化学检测的原理、方法和潜在的应用.     

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...     

脉冲电沉积Pd-Ni合金纳米颗粒及其甲酸电催化氧化

采用方波脉冲方法,在钯镍合金电解液中成功地电化学沉积出镍原子含量分别为12.0%、16.4%和22.6%的钯镍合金纳米颗粒. 钯镍合金纳米颗粒为球状,粒径50 ~ 80 nm. 随钯镍合金生长电位负移,合金的镍含量提高,其纳米颗粒大小基本相似但纳米颗粒数目增多,交联度提高和真实活性面积增大. 钯镍合金纳米颗粒镍含量提高,在硫酸溶液中其氢弱吸附峰电流增大. 钯镍合金纳米颗粒电极的甲酸电催化氧化活性较好,随合金纳米颗粒的镍含量提高和交联度增加,合金纳米颗粒电极的甲酸电催化氧化稳定性更高.     

脉冲电沉积钯镍合金纳米颗粒及其甲酸电催化氧化

采用方波脉冲方法,在钯镍合金电解液中成功地电化学沉积出镍原子含量分别为12.0%、16.4%和22.6%的钯镍合金纳米颗粒.钯镍合金纳米颗粒为球状,粒径50~80 nm.随钯镍合金生长电位负移,合金的镍含量提高,其纳米颗粒大小基本相似但纳米颗粒数目增多,交联度提高和真实活性面积增大.钯镍合金纳米颗粒镍含量提高,在硫酸溶液中其氢弱吸附峰电流增大.钯镍合金纳米颗粒电极的甲酸电催化氧化活性较好,随合金纳米颗粒的镍含量提高和交联度增加,合金纳米颗粒电极的甲酸电催化氧化稳定性更高.     

三层同轴电喷-去模板法制备核壳纳米颗粒用于蛋白质药物输送

分别以聚乙二醇(PEG)、聚(丙交酯-乙交酯)(PLGA)和牛血清白蛋白(BSA)为冠、壳和核层材料,采用三层同轴电喷技术制备得到微米颗粒.激光共聚焦显微镜(LSCM)显示,该方法制备得到的微米颗粒呈现核-壳-冠结构.通过脱去该微米颗粒的PEG冠层(模板),得到包载有BSA的纳米颗粒.研究发现,随着壳层PLGA溶液进样速度的减慢,去模板后纳米颗粒的粒径从约146 nm减小到68 nm.BSA在纳米颗粒中的包埋率可高达78.3%,并且其释放没有显著的药物暴释现象.圆二色谱结果表明,同轴电喷过程对BSA二级结构影响很小.因此,利用三层同轴电喷-去模板法可制备得到粒径可调控的蛋白质纳米载体系统,并且该过程中蛋白质的结构基本维持不变.     

类脂囊泡作为5-氟尿嘧啶药物载体的研究

采用薄膜分散法,以司盘类非离子表面活性剂和胆固醇为主要原料,制备抗肿瘤药物5-氟尿嘧啶(5-FU)类脂囊泡.以包封率为考察指标,对可能影响包封的各种实验条件进行优化.实验表明:药物浓度为1.0 g/L,Span 20与胆固醇比例为4∶3,50℃超声30min,所制得的5-FU类脂囊泡的包封率可达40%以上.透射电镜照片显示所制得的类脂囊泡为球形单室结构,测得平均粒径为393nm,且分布较均匀,表明制得的囊泡粒径符合注射给药的要求.     

Mesoporous silica spheres from colloids

A novel method has been developed to synthesize mesoporous silica spheres using commercial silica colloids (SNOWTEX) as precursors and electrolytes (ammonium nitrate and sodium chloride) as destabilizers. Crosslinked polyacrylamide hydrogel was used as a temporary barrier to obtain dispersible spherical mesoporous silica particles. The influences of synthesis conditions including solution composition and calcination temperature on the formation of the mesoporous silica particles were systematically investigated. The structure and morphology of the mesoporous silica particles were characterized via scanning electron microscopy (SEM) and N2 sorption technique. Mesoporous silica particles with particle diameters ranging from 0.5 to 1.6 microm were produced whilst the BET surface area was in the range of 31-123 m2 g-1. Their pore size could be adjusted from 14.1 to 28.8 nm by increasing the starting particle diameter from 20-30 nm up to 70-100 nm. A simple and cost effective method is reported that should open up new opportunities for the synthesis of scalable host materials with controllable structures.     

Surfactant addition and alternating current electrophoretic oscillation during size fractionation of nanoparticles in channels with two or three different height segments

An array of parallel planar nanochannels containing two or three segments with varying inner heights was fabricated and used for size fractionation of inorganic and biological nanoparticles. A liquid suspension of the particles was simply drawn through the nanochannels via capillary action. Using fluorescently labeled 30 nm polyacrylonitrile beads, different trapping behaviors were compared using nanochannels with 200-45 nm and 208-54-30 nm height segments. Addition of sodium dodecyl sulfate (SDS) surfactant to the liquid suspension and application of an AC electric field were shown to aid in the prevention of channel clogging. After initial particle trapping at the segment interfaces, significant particle redistribution occurred when applying a sinusoidal 8V peak-to-peak oscillating voltage with a frequency of 150 Hz and DC offset of 4V. Using the 208-54-30 nm channels, 30 nm hepatitis B virus (HBV) capsids were divided into three fractions. When the AC electric field was applied to this trapped sample, all of the virus particles passed through the interfaces and accumulated at the channel ends.     

Fine-tuning of catalytic tin nanoparticles by the reverse micelle method for direct deposition of silicon nanowires by a plasma-enhanced chemical vapour technique

The reverse micelle method was used for the reduction of a tin (Sn) salt solution to produce metallic Sn nanoparticles ranging from 85 nm to 140 nm in diameter. The reverse micellar system used in this process was hexane-butanol-cetyl trimethylammonium bromide (CTAB). The diameters of the Sn nanoparticles were proportional to the concentration of the aqueous Sn salt solution. Thus, the size of the Sn nanoparticles can easily be controlled, enabling a simple, reproducible mechanism for the growth of silicon nanowires (SiNWs) using plasma-enhanced chemical vapour deposition (PECVD). Both the Sn nanoparticles and silicon nanowires were characterised using field-emission scanning electron microscopy (FE-SEM). Further characterisations of the SiNW's were made using transmission electron microscopy (TEM), atomic force microscopy (AFM) and Raman spectroscopy. In addition, dynamic light scattering (DLS) was used to investigate particle size distributions. This procedure demonstrates an economical route for manufacturing reproducible silicon nanowires using fine-tuned Sn nanoparticles for possible solar cell applications.     

Synthesis of silica nanoparticles using oil-in-water emulsion and the porosity analysis

A set of silica particles was synthesized in oil–in–water emulsion with particle diameters ranging from ~42?nm to ~115?nm approximately. The porosity of the nanoparticles was analyzed using conventional nitrogen sorption and positron annihilation lifetime spectroscopy (PALS) techniques. The isotherm obtained using nitrogen sorption indicated that the particles were ‘non-porous?? however fitting data with Density Functional Theory model revealed a low concentration pore with diameters from 1.4?nm to 1.7?nm. The pore size was independent of the particle size. In contrast, analysis with PALS revealed a single pore size of ~0.6?nm present in all samples. Difference in results obtained for micropores <4?nm diameter is proposed to be dependent on models used and sample conditions for analysis.     

Extinction coefficient of gold nanoparticles with different sizes and different capping ligands

Extinction coefficients of gold nanoparticles with core size ranging from approximately 4 to 40 nm were determined by high resolution transmission electron microscopy analysis and UV-vis absorption spectroscopic measurement. Three different types of gold nanoparticles were prepared and studied: citrate-stabilized nanoparticles in five different sizes; oleylamide-protected gold nanoparticles with a core diameter of 8 nm, and a decanethiol-protected nanoparticle with a diameter of around 4 nm. A linear relationship between the logarithms of extinction coefficients and core diameters of gold particles was found independent of the capping ligands on the particle surface and the solvents used to dissolve the nanoparticles. This linear relation may be used as a calibration curve to determine the concentration or average size of an unknown nanoparticle or nanoparticle-biomolecule conjugate sample.     

可聚合囊泡体系(烯丙基-二甲基-十二烷基溴化胺和十二烷基硫酸钠)在溶液中的盐效应

高稳定的囊泡广泛用于制作生物模型、药物输送以及合成纳米材料的模板。获得高稳定囊泡结构的重要方法之一是用聚合反应固定囊泡结构。作为可聚合囊泡制备的前期基础工作,研究了一种可聚合的囊泡体系：1-丙烯基－2,2,二甲基－十二烷基溴化胺（ADDB）和ADDB与十二烷基磺酸钠（SDS）的等摩尔比混合体系。该囊泡体系即使在高浓度盐水中也能够自发地形成均相的囊泡溶液。在聚合之前,采用动态激光光散射（DLS）、冷冻蚀刻透射电镜（FF-TEM）技术研究了可聚合囊泡的盐效应。DLS测试发现没有盐存在时,囊泡大小为83 nm,盐的浓度增加到250 mmol/L时,囊泡尺寸增大到250 nm。然而继续增大盐浓度到1000 mmol/L, 囊泡尺寸减小到180nm. FF-TEM结果发现盐浓度小于150 mM时, 单个囊泡为70 nm左右,然而明显存在囊泡的絮凝与融合;当盐浓度增加到400 mM时,单个囊泡尺寸减小到20 nm. 因此DLS 观测到囊泡尺寸增大的原因是由于囊泡的絮凝与融合;而尺寸减小的原因是由于在高盐浓度下,盐屏蔽了带电颗粒之间的静电相互作用,在熵增的驱使下,大囊泡变成小囊泡。     

Fabrication and characterization of homogeneous surface-enhanced Raman scattering substrates by single pulse UV-laser treatment of gold and silver films

The fabrication of SERS-active substrates, which offer high enhancement factors as well as spatially homogeneous distribution of the enhancement, plays an important role in the expansion of surface-enhanced Raman scattering (SERS) spectroscopy to a powerful, quantitative, and noninvasive measurement technique for analytical applications. In this paper, a novel method for the fabrication of SERS-active substrates by laser treatment of 20, 40, and 60 nm thick gold and of 40 nm thick silver films supported on quartz glass is presented. Single 308 nm UV-laser pulses were applied to melt the thin gold and silver films. During the cooling process of the noble metal, particles were formed. The particle size and density were imaged by atomic force microscopy. By varying the fluence, the size of the particles can be controlled. The enhancement factors of the nanostructures were determined by recording self-assembled monolayers of benzenethiol. The intensity of the SERS signal from benzenethiol is correlated to the mean particle size and thus to the fluence. Enhancement factors up to 10(6) with a high reproducibility were reached. Finally we have analyzed the temperature dependence of the SERS effect by recording the intensity of benzenethiol vibrations from 300 to 120 K. The temperature dependence of the SERS effect is discussed with regard to the metal properties.     

Adsorption energetics of CO on supported Pd nanoparticles as a function of particle size by single crystal microcalorimetry

The heat of adsorption and sticking probability of CO on well-defined Pd nanoparticles were measured as a function of particle size using single crystal adsorption microcalorimetry. Pd particles of different average sizes ranging from 120 to 4900 atoms per particle (or from 1.8 to 8 nm) and Pd(111) were used that were supported on a model in situ grown Fe(3)O(4)/Pt(111) oxide film. To precisely quantify the adsorption energies, the reflectivities of the investigated model surfaces were measured as a function of the thickness of the Fe(3)O(4) oxide layer and the amount of deposited Pd. A substantial decrease of the binding energy of CO was found with decreasing particle size. Initial heat of adsorption obtained on the virtually adsorbate-free surface was observed to be reduced by about 20-40 kJ mol(-1) on the smallest 1.8 nm sized Pd particles as compared to the larger Pd clusters and the extended Pd(111) single crystal surface. This effect is discussed in terms of the size-dependent properties of the Pd nanoparticles. The CO adsorption kinetics indicates a strong enhancement of the adsorbate flux onto the metal particles due to a capture zone effect, which involves trapping of adsorbates on the support and diffusion to metal clusters. The CO adsorption rate was found to be enhanced by a factor of ～8 for the smallest 1.8 nm sized particles and by ～1.4 for the particles of 7-8 nm size.     

Preparation of crystalline gold nanoparticles at the surface of mixed phosphatidylcholine-ionic surfactant vesicles

The formation of gold nanoparticles and the crystal growth at the surface of mixed phosphatidylcholine (PC)-ionic surfactant vesicles was investigated. The PC-bilayer surface was negatively charged by incorporating sodium dodecyl sulfate (SDS) and positively charged by adding hexadecyltrimethylammonium chloride (CTAB). The mass ratio phosphatidylcholine:surfactant was fixed in both cases at 1:1. The gold nanoparticle formation was studied by using transmission electron microscopy (TEM) combined with dynamic light scattering (DLS) and UV-vis absorption spectroscopy. TEM micrographs confirm that the particle formation occurs on the vesicle surface. However, the reduction process depends on the ionic surfactant incorporated into the vesicles, the vesicle size distribution, as well as the temperature used for the reduction process. Thereby, it becomes possible to control the crystal growth of the individual spherical gold nanoparticles in a characteristic way. Red colored colloidal dispersions consisting of monodisperse spherical nanoparticles with an average particle size between 2 and 8 nm (determined by dynamic light scattering) can be obtained by using a monodisperse SDS-modified vesicle phase. When the temperature is increased to 45 degrees C, a crystallization in rod-like or triangular structures is observed. In the CTAB-based template phase in general larger gold particles of about 35 nm are formed. In similarity to the anionic vesicles a temperature increase leads to the crystallization in triangular structures.     

Influence of nanotopography on phospholipid bilayer formation on silicon dioxide

We have investigated the effect of well-defined nanoscale topography on the 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid vesicle adsorption and supported phospholipid bilayer (SPB) formation on SiO2 surfaces using a quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). Unilamellar lipid vesicles with two different sizes, 30 and 100 nm, were adsorbed on pitted surfaces with two different pit diameters, 110 and 190 nm, as produced by colloidal lithography, and the behavior was compared to results obtained on flat surfaces. In all cases, complete bilayer formation was observed after a critical coverage of adsorbed vesicles had been reached. However, the kinetics of the vesicle-to-bilayer transformation, including the critical coverage, was significantly altered by surface topography for both vesicle sizes. Surface topography hampered the overall bilayer formation kinetics for the smaller vesicles, but promoted SPB formation for the larger vesicles. Depending on vesicle size, we propose two modifications of the precursor-mediated vesicle-to-bilayer transformation mechanism used to describe supported lipid bilayer formation on the corresponding flat surface. Our results may have important implications for various lipid-membrane-based applications using rough or topographically structured surfaces.