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1.
Dark‐Field‐Based Observation of Single‐Nanoparticle Dynamics on a Supported Lipid Bilayer for In Situ Analysis of Interacting Molecules and Nanoparticles 下载免费PDF全文
Observation of single plasmonic nanoparticles in reconstituted biological systems allows us to obtain snapshots of dynamic processes between molecules and nanoparticles with unprecedented spatiotemporal resolution and single‐molecule/single‐particle‐level data acquisition. This Concept is intended to introduce nanoparticle‐tethered supported lipid bilayer platforms that allow for the dynamic confinement of nanoparticles on a two‐dimensional fluidic surface. The dark‐field‐based long‐term, stable, real‐time observation of freely diffusing plasmonic nanoparticles on a lipid bilayer enables one to extract a broad range of information about interparticle and molecular interactions throughout the entire reaction period. Herein, we highlight important developments in this context to provide ideas on how molecular interactions can be interpreted by monitoring dynamic behaviors and optical signals of laterally mobile nanoparticles. 相似文献
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Aila Jimenez‐Ruiz Prof. Pilar Perez‐Tejeda Prof. Elia Grueso Dr. Paula M. Castillo Prof. Rafael Prado‐Gotor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9596-9609
Since Faraday first described gold sol synthesis, synthetic routes to nanoparticles, as well as their applications, have experienced a huge growth. Variations in synthesis conditions such as pH, temperature, reduction, and the stabilizing agent used will determine the morphology, size, monodispersity, and stability of nanoparticles obtained, allowing for modulation of their physical and chemical properties. Although many studies have been made about the synthesis and characterization of individual nanosystems of interest, to our knowledge the common, general traits that all those synthesis share have not been previously compiled. In this review, we aim to offer a global vision of some of the most relevant synthetic procedures reported up to date, with a special focus on nonfunctionalized gold nanoparticle synthetic routes in aqueous media, and to display a broad overview of the influence that synthesis conditions have on the shape, stability, and reactivity of nanoparticle systems. 相似文献
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Assessing the Role of Capping Molecules in Controlling Aggregative Growth of Gold Nanoparticles in Heated Solution 下载免费PDF全文
This report describes findings of an investigation of the role of capping molecules in the size growth in the aggregative growth of pre‐formed small‐sized gold nanoparticles capped with alkanethiolate monolayers toward monodispersed larger sizes. The size controllability depends on the thiolate chain length and concentration in the thermal solution. The size evolution in solution at different concentrations of alkanethiols is analyzed in relation to adsorption isotherms and cohesive energy. The size dependence on thiolate chain length is also analyzed by considering the cohesive energy of the capping molecules, revealing the importance of cohesive energy in the capping structure. Theoretical and experimental comparisons of the surface plasmonic resonance optical properties have also provided new insights into the mechanism, thus enabling the exploitation of size‐dependent nanoscale properties. 相似文献
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纳米材料特有的尺寸效应、量子效应和表面效应使其具有许多异于常规材料的性质 ,在催化、生物传感器、微电子器件和磁性材料等诸多领域都有广泛的应用前景 [1] .已有专家预言 ,与纳米材料相关的技术将在新世纪经济发展中起主导作用 ,对其研究是目前科学研究中的热点 .金纳米颗粒是目前研究得最多的金属纳米材料体系 .传统的金纳米颗粒的制备方法以溶胶 -凝胶法为主 [2~ 4 ] ,所制备的金纳米颗粒的粒径较大 (一般大于 1 0 nm) ,粒径分布不均匀 ,易于团聚 ,因而限制了其应用 .为了解决上述问题 ,Brust等 [5]将硫醇化合物在金属表面的自组装… 相似文献
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甲烷氧化菌素(methanobactin,mb)是具有过氧化氢还原酶活性的荧光肽.从甲基弯菌Methylosinus trichospo-rium IMV3011限铜培养介质中分离mb,采用紫外可见全波长扫描法观察mb催化对苯二酚还原氯金酸合成纳米金的作用和影响,当mb/氯金酸/对苯二酚反应液中mb的浓度分别是2.5×10-5mol/L、5.0×10-5mol/L和1.0×10-4mol/L时,形成的纳米金溶液的特征峰分别是561.5 nm(OD561=0.158)、548.0 nm(OD5 48=0.426)、536.5 nm(OD5 36=0.541),特征峰波长减小,对应的吸光值增大,表明mb能够催化对苯二酚还原氯金酸合成纳米金,并且可以通过调控mb的浓度控制纳米金的合成量及粒径大小. 相似文献
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Size‐Dependent Electrocatalytic Activity of Free Gold Nanoparticles for the Glucose Oxidation Reaction 下载免费PDF全文
Dr. Seydou Hebié Dr. Teko W. Napporn Dr. Cláudia Morais Prof. Dr. K. Boniface Kokoh 《Chemphyschem》2016,17(10):1454-1462
Understanding the fundamental relationship between the size and the structure of electrode materials is essential to design catalysts and enhance their activity. Therefore, spherical gold nanoparticles (GNSs) with a mean diameter from 4 to 15 nm were synthesized. UV/Vis spectroscopy, transmission electron microscopy, and under‐potential deposition of lead (UPDPb) were used to determine the morphology, size, and surface crystallographic structure of the GNSs. The UPDPb revealed that their crystallographic facets are affected by their size and the growth process. The catalytic properties of these GNSs toward glucose electrooxidation were studied by cyclic voltammetry, taking into account the scan rate and temperature effects. The results clearly show the size‐dependent electrocatalytic activity for glucose oxidation reactions that are controlled by diffusion. Small GNSs with an average size of 4.2 nm exhibited high catalytic activity. This drastic increase in activity results from the high specific area and reactivity of the surface electrons induced by their small size. The reaction mechanism was investigated by in situ Fourier transform infrared reflectance spectroscopy. Gluconolactone and gluconate were identified as the intermediate and the final reaction product, respectively, of the glucose electrooxidation. 相似文献
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Voltage‐Driven Reversible Insertion into and Leaving from a Lipid Bilayer: Tuning Transmembrane Transport of Artificial Channels 下载免费PDF全文
Wen Si Prof. Zhan‐Ting Li Prof. Jun‐Li Hou 《Angewandte Chemie (International ed. in English)》2014,53(18):4578-4581
Three new artificial transmembrane channel molecules have been designed and synthesized by attaching positively charged Arg‐incorporated tripeptide chains to pillar[5]arene. Fluorescent and patch‐clamp experiments revealed that voltage can drive the molecules to insert into and leave from a lipid bilayer and thus switch on and off the transport of K+ ions. One of the molecules was found to display antimicrobial activity toward Bacillus subtilis with half maximal inhibitory concentration (IC50) of 10 μM which is comparable to that of natural channel‐forming peptide alamethicin. 相似文献
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David A. Giljohann Dr. Dwight S. Seferos Dr. Weston L. Daniel Matthew D. Massich Pinal C. Patel Chad A. Mirkin Prof. 《Angewandte Chemie (International ed. in English)》2010,49(19):3280-3294
Gold colloids have fascinated scientists for over a century and are now heavily utilized in chemistry, biology, engineering, and medicine. Today these materials can be synthesized reproducibly, modified with seemingly limitless chemical functional groups, and, in certain cases, characterized with atomic‐level precision. This Review highlights recent advances in the synthesis, bioconjugation, and cellular uses of gold nanoconjugates. There are now many examples of highly sensitive and selective assays based upon gold nanoconjugates. In recent years, focus has turned to therapeutic possibilities for such materials. Structures which behave as gene‐regulating agents, drug carriers, imaging agents, and photoresponsive therapeutics have been developed and studied in the context of cells and many debilitating diseases. These structures are not simply chosen as alternatives to molecule‐based systems, but rather for their new physical and chemical properties, which confer substantive advantages in cellular and medical applications. 相似文献
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Jian‐Qin Gu Dr. Ling‐Dong Sun Prof. Dr. Zheng‐Guang Yan Dr. Chun‐Hua Yan Prof. Dr. 《化学:亚洲杂志》2008,3(10):1857-1864
This work demonstrates luminescence resonance energy transfer (LRET) sensors based on lanthanide‐doped nanoparticles as donors (D) and gold nanoparticles as acceptors (A), combined through electrostatic interactions between the oppositely charged nanoparticles. Negatively charged lanthanide‐doped nanoparticles, YVO4:Eu and LaPO4:Ce,Tb, with high luminescence quantum yield and good water‐solubility, are synthesized through a polymer‐assisted hydrothermal method. Positively charged polyhedral and spherical gold nanoparticles exhibit surface plasmon resonance (SPR) bands centered at 623 and 535 nm, respectively. These bands overlap well with the emission of the Eu3+ and Tb3+ ions within the lanthanide nanoparticles. Herein, the gold nanoparticles are synthesized through a seed‐mediated cetyltrimethylammonium bromide (CTAB)‐assisted method. The assemblies of the oppositely charged donors and acceptors are developed into LRET‐based sensors exhibiting a donor quenching efficiency close to 100 %. 相似文献
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Size of Gold Nanoparticles Driving Selective Amide Synthesis through Aerobic Condensation of Aldehydes and Amines 下载免费PDF全文
Dr. Hiroyuki Miyamura Hyemin Min Dr. Jean‐François Soulé Prof. Dr. Shū Kobayashi 《Angewandte Chemie (International ed. in English)》2015,54(26):7564-7567
Metal nanoparticles (NPs) have attracted much attention in many fields due to their intrinsic characteristics. It is generally accepted that smaller NPs (1.5–3 nm) are more active than larger NPs, and reverse cases are very rare. We report here the direct aerobic oxidative amide synthesis from aldehydes and amines catalyzed by polymer‐incarcerated gold (Au) NPs. A unique correlation between imine/amide selectivity and size of NPs was discovered; Au‐NPs of medium size (4.5–11 nm) were found to be optimal. High yields were obtained with a broad range of substrates, including primary amines. Au‐NPs of medium size could be recovered and reused several times without loss of activity, and they showed good activity and selectivity in amide formation from alcohols and amines. 相似文献
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Sheng Wang Prof. Dr. Wei Chen Prof. Dr. Ai‐Lin Liu Lei Hong Hao‐Hua Deng Prof. Xin‐Hua Lin 《Chemphyschem》2012,13(5):1199-1204
The origin of the peroxidase‐like activity of gold nanoparticles and the impact of surface modification are studied. Furthermore, some influencing factors, such as fabrication process, redox property of the modifier, and charge property of the substrate, are investigated. Compared to amino‐modified or citrate‐capped gold nanoparticles, unmodified gold nanoparticles show significantly higher catalytic activity toward peroxidase substrates, that is, the superficial gold atoms are a contributing factor to the observed peroxidase‐like activity. The different catalytic activities of amino‐modified and citrate‐capped gold nanoparticles toward 3,3′,5,5′‐tetramethylbenzidine (TMB) and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt (ABTS) show that the charge characteristics of the nanoparticles and the substrate also play an important role in the catalytic reactions. 相似文献
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Dr. Alice Boccia Dr. Fabio D'Orazi Dr. Elena Carabelli Dr. Rocco Bussolati Prof. Arturo Arduini Prof. Andrea Secchi Dr. Andrea G. Marrani Prof. Robertino Zanoni 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(24):7999-8006
The assembly of gold nanoparticles (AuNPs) on a hydrogenated Si(100) surface, mediated by a series of hierarchical and reversible complexation processes, is reported. The proposed multi‐step sequence involves a redox‐active ditopic guest and suitable calix[n]arene‐based hosts, used as functional organic monolayers of the two inorganic components. Surface reactions and controlled release of AuNPs have been monitored by application of XPS, atomic force microscopy (AFM), field‐emission scanning electron microscopy (FESEM) and electrochemistry. 相似文献
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Dr. Jianxiu Du Yadi Wang Weimin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(27):8540-8546
A label‐free, non‐derivatization chemiluminescence resonance energy transfer (CRET) detection platform has been developed for the detection of the non‐fluorescent small molecule 6‐mercaptopurine. This CRET process arose from a chemiluminescent (CL) donor–acceptor system in which the reaction of bis(2,4,6‐trichlorophenyl)oxalate (TCPO)–H2O2–fluorescein (maximum emission at 521.6 nm) served as the donor and gold nanoparticles (AuNPs, maximum absorption at 520.0 nm) served as the acceptor. This process caused a significant decrease in the CL signal of the TCPO–H2O2–fluorescein reaction. The presence of 6‐mercaptopurine induced an aggregation of AuNPs with the assistance of Cu2+ ions through cooperative metal–ligand interactions that was accompanied by a distinct change in color and optical properties. The maximum absorption band of the AuNPs was red‐shifted to 721.0 nm and no longer overlapped with the CL spectrum of the reaction; as a result, the CL signal was restored. This CRET system exhibited a wide linear range, from 9.0 nmol L?1 to 18.0 μmol L?1, and a low detection limit (0.62 nmol L?1) for 6‐mercaptopurine. The applicability of the proposed CRET system was evaluated by analysis of 6‐mercaptopurine in spiked human plasma samples. 相似文献
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金纳米颗粒是近年研究的一种热门材料。介绍了金纳米颗粒主要的制备方法,包括化学还原法,两相法,晶种生长法以及模板法,并总结了金纳米粒子在生物医学、传感器、催化剂、电化学等领域的应用进展。 相似文献
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Dr. Kouta Sugikawa Tatsuya Kadota Dr. Kazuma Yasuhara Prof. Atsushi Ikeda 《Angewandte Chemie (International ed. in English)》2016,55(12):4059-4063
The behavior of self‐assembly processes of nanoscale particles on plasma membranes can reveal mechanisms of important biofunctions and/or intractable diseases. Self‐assembly of citrate‐coated gold nanoparticles (cAuNPs) on liposomes was investigated. The adsorbed cAuNPs were initially fixed on the liposome surfaces and did not self‐assemble below the phospholipid phase transition temperature (Tm). In contrast, anisotropic cAuNP self‐assembly was observed upon heating of the composite above the Tm, where the phospholipids became fluid. The number of self‐assembled NPs is conveniently controlled by the initial mixing ratio of cAuNPs and liposomes. Gold nanoparticle protecting agents strongly affected the self‐assembly process on the fluidic membrane. 相似文献
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Thathan Premkumar Dongsik Kim Kyungjae Lee Kurt E. Geckeler 《Macromolecular rapid communications》2007,28(7):888-893
The preparation of metal nanoparticles generally requires the use of mostly toxic reducing agents according to state‐of‐the‐art procedures. Here, we report that polysorbate 80, a polymeric nonionic surfactant, when reacted with a gold salt in water at room temperature, yields well‐dispersed gold nanoparticles. Furthermore, we could control the particle size by simply altering concentration or temperature. The synthetic procedure presented here is easy, inexpensive, straightforward, and user‐friendly.
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Hao Qi Brandy Kinkead Vanessa M. Marx Huai R. Zhang Dr. Torsten Hegmann Dr. 《Chemphyschem》2009,10(8):1211-1218
Against the rule: Liquid crystal hosts ( 5CB and 8CB ) are doped with different thiol decorated gold nanoparticles (see figure). The “simple” hexanethiol and dodecanethiol capped nanoparticles ( Au1 and Au2 ) are more compatible to the nematic cyanobiphenyl liquid crystals than nanoparticles capped simultaneously with alkylthiols and a nematic cyanobiphenyl thiol ( Au3 and Au4 ).
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Local Geometric Effects on Stability and Energy Gap of Thiolate‐Protected Gold Nanoparticles 下载免费PDF全文
YiFan Bu Prof. Dr. Ming Zhao Prof. Dr. Yuquan He Prof. Dr. Wang Gao Prof. Dr. Qing Jiang 《Chemphyschem》2016,17(19):2998-3003
Thiolate‐protected gold nanoclusters, Aum(SR)n, have potential applications in many fields due to their high stability and remarkable electronic properties. However, the controlling factors in determining the stability and HOMO–LUMO gap of Aum(SR)n remain controversial, despite decades of work on the topic. Through DFT calculations, including nonlocal many‐body dispersion (MBD) interactions, the geometric and electronic properties of Aum(SR)n clusters are investigated. Calculations demonstrate that the MBD interactions are essential for correctly describing the geometry and energy of the clusters. Greater anisotropic polarization and more atoms distributed in the shell of the clusters lead to more pronounced MBD interactions and higher stability of the clusters. Furthermore, the HOMO–LUMO gap of the clusters strongly depends on the gold core. These results provide critical clues for understanding and designing Aum(SR)n clusters. 相似文献