基于金纳米结构的光谱探针在传感器中的应用

近年来,金纳米结构因为具有高比表面积、表面易于修饰、优良的生物相容性以及表面等离子体共振等独特性质而备受研究者们的青睐,基于金纳米结构独特的光学特性,可以作为优良的光学探针应用于化学和生物传感。为了更好的了解金纳米结构在现代科学中的重要作用,总结金纳米结构在传感器中的应用十分必要,因此本文主要综述了近几年金纳米结构作为光学探针在生物和化学传感方面的应用,并对金纳米结构未来的发展前景进行了展望。     

金纳米棒表面修饰技术及其功能化的研究进展

各向异性的金纳米棒由于具有独特的光学性质、较好的生物适应性,在生物医学领域得到了日益广泛的应用。本文系统评述了金纳米棒的表面修饰技术及其功能化的研究进展,内容包括:①金纳米棒的无机材料修饰,表面活性剂修饰、有机小分子及有机大分子修饰、金属材料修饰及其功能化;②金纳米棒在生物标记与识别、生物成像、癌症诊断和光热治疗等领域中的应用。     

金纳米棒合成与自组装的研究进展

与球形金颗粒相比,各向异性的金纳米棒同时具有化学和光学上的各向异性,其更为特殊的表面等离子共振（SPR）特性和基于表面SPR的强吸收和发光特性,在材料科学和生物医学领域中存在着巨大的应用前景。本文主要评述了金纳米棒合成与组装的最新研究进展,具体内容包括：金纳米棒的合成、模板诱导的金纳米棒的自组装、表面张力诱导的金纳米棒的自组装及应用。     

金纳米棒的合成及应用研究进展

金纳米材料具有特殊的物理、化学性质。与其他形状的金纳米材料相比,金纳米棒同时具有化学和光学方面的备向异性,在材料科学、局域表面等离子体共振（LSPR）传感、生物医学等领域存在着巨大的应用前景。文章系统的评述了金纳米棒的合成及应用进展。具体内容包括金纳米棒的合成、金纳米棒的光学特性、金纳米棒在LSPR传感分析方面的应用以及金纳米棒在生物医学方面的应用。     

金纳米结构表面形貌对吸收-发光特性调控研究

贵金属纳米结构的光学性质是近年来微纳光学领域的研究热点之一,其中,金纳米棒表面等离激元共振局域特性,由于其易于调控,越来越受到人们的广泛关注。利用种子水热法合成制备了金纳米棒结构,通过不同温度的二次水热生长处理,改变了其表面结构形貌,实现了其表面等离激元共振吸收峰峰位的调控,并且通过进一步光致发光光谱以及时间分辨光谱的测试,分析了其形貌结构对表面等离激元与外界光场能量耦合效率的影响,这不仅对小尺寸金属纳米结构等离激元共振模式进行了初步的探索,也为后续微纳光学纳米器件的开发利用提供了理论及实验参考依据。     

金纳米粒子的研究进展

纳米科学是一个正在蓬勃发展的学科,它的发展对其他科学领域都有重要的影响,其中有一大领域的纳米粒子已经近被人们广泛研究,金纳米粒子就是其中较为典型的一个代表。它在生物标记、传感器构建、光学探针、电化学探针、组织修复、DNA、葡萄糖传感器等领域都有重要应用。     

纳米金-寡核苷酸探针的制备及其应用

纳米金-寡核苷酸探针正引起科学家们越来越多的兴趣，文章综述了影响纳米金表面DNA组装的因素以及纳米金-寡核苷酸探针在生物检测中的应用。     

金纳米的制备及其应用研究进展

介绍了金纳米的光学性质及制备的研究进展,总结了空心金纳米球、金纳米棒及金纳米簇在食品检测、催化、有毒有害物质的检测及生物医学领域的显著应用。并对今后的研究重点进行了展望。     

上海应物所在DNA分子介导的金属等离子体纳米结构研究方面取得进展

正金属纳米结构在与光相互作用时会产生特定的表面等离子体共振。这种基于金属纳米结构的表面等离子体光学(plasmonics)在生物传感、生物成像、光催化和太阳能电池等领域具有广泛的应用前景。近期,上海应用物理研究所物理生物学研究室樊春海课题组和上海光源陈刚课题组利用DNA分子实现了对金纳米等     

局域表面等离子体共振辅助的金纳米棒/聚合物纳米复合材料的双光子聚合

本文研究了金纳米棒的局域表面等离子体共振效应在双光子聚合过程中的作用,即当激发光与金纳米棒表面等离子体共振波长相匹配时,会在金纳米棒表面产生很强的局域电磁场,从而引发双光子聚合。通过采用与金纳米棒表面等离子体共振波长相同的飞秒激光,在低于光刻胶聚合阈值的功率下照射舍有金纳米棒的光刻胶,制备聚合物包覆金纳米棒的纳米复合材料。透射电子显微镜结果表明,当飞秒激光功率为0.6 W、光斑直径为1.6 cm、照射时间为0.3 s时,金纳米棒表面成功聚合上厚度为5 nm左右的聚合物。本研究在制备聚合物/金属纳米粒子方面提供了一种简单可行的方法,有望在纳米光子学、纳米传感器等新兴领域得到应用。     

Conversion of rod-shaped gold nanoparticles to spherical forms and their effect on biodistribution in tumor-bearing mice

Gold nanorods that have an absorption band in the near-infrared region and a photothermal effect have been used as nanodevices for near-infrared imaging and thermal therapy. Choice of the optimal shape of gold nanorods which relates optical properties and in vivo biodistribution is important for their applications. In the present study, to investigate the relationship between the shape of gold nanorods and their biodistribution after intravenous injection, we first prepared two types of gold nanorods that had distinct aspect ratios but had the same volume, zeta potential, and PEG density on the gold surface. Biodistributions of the two types of gold nanorods after intravenous injection into tumor-bearing mice were then compared. Although a slight difference in accumulation in the spleen was observed, no significant difference was observed in the liver, lung, kidney, and tumors. These results suggest that biodistribution of the gold nanorods in the aspect ratio range of 1.7 to 5.0, diameter of 10 to 50 nm, and volume of approximately 4 × 10³ nm³ was dependent mainly on surface characteristics, PEG density, and zeta potential.     

Noble metals on the nanoscale: optical and photothermal properties and some applications in imaging, sensing, biology, and medicine

Noble metal nanostructures attract much interest because of their unique properties, including large optical field enhancements resulting in the strong scattering and absorption of light. The enhancement in the optical and photothermal properties of noble metal nanoparticles arises from resonant oscillation of their free electrons in the presence of light, also known as localized surface plasmon resonance (LSPR). The plasmon resonance can either radiate light (Mie scattering), a process that finds great utility in optical and imaging fields, or be rapidly converted to heat (absorption); the latter mechanism of dissipation has opened up applications in several new areas. The ability to integrate metal nanoparticles into biological systems has had greatest impact in biology and biomedicine. In this Account, we discuss the plasmonic properties of gold and silver nanostructures and present examples of how they are being utilized for biodiagnostics, biophysical studies, and medical therapy. For instance, taking advantage of the strong LSPR scattering of gold nanoparticles conjugated with specific targeting molecules allows the molecule-specific imaging and diagnosis of diseases such as cancer. We emphasize in particular how the unique tunability of the plasmon resonance properties of metal nanoparticles through variation of their size, shape, composition, and medium allows chemists to design nanostructures geared for specific bio-applications. We discuss some interesting nanostructure geometries, including nanorods, nanoshells, and nanoparticle pairs, that exhibit dramatically enhanced and tunable plasmon resonances, making them highly suitable for bio-applications. Tuning the nanostructure shape (e.g., nanoprisms, nanorods, or nanoshells) is another means of enhancing the sensitivity of the LSPR to the nanoparticle environment and, thereby, designing effective biosensing agents. Metal nanoparticle pairs or assemblies display distance-dependent plasmon resonances as a result of field coupling. A universal scaling model, relating the plasmon resonance frequency to the interparticle distance in terms of the particle size, becomes potentially useful for measuring nanoscale distances (and their changes) in biological systems. The strong plasmon absorption and photothermal conversion of gold nanoparticles has been exploited in cancer therapy through the selective localized photothermal heating of cancer cells. For nanorods or nanoshells, the LSPR can be tuned to the near-infrared region, making it possible to perform in vivo imaging and therapy. The examples of the applications of noble metal nanostructures provided herein can be readily generalized to other areas of biology and medicine because plasmonic nanomaterials exhibit great range, versatility, and systematic tunability of their optical attributes.     

关于金纳米棒应用的研究进展

介绍了金纳米棒的物理和化学性质及应用新进展,重点综述了金纳米棒在自组装、金属离子检测、DNA检测、小分子及生物小分子检测方面的研究。展望了其广阔的发展和应用前景,对以后的研究重点和发展方向进行了讨论。     

Creation and luminescence of size-selected gold nanorods

Fluorescent metal nanoparticles have attracted great interest in recent years for their unique properties and potential applications. Their optical behaviour depends not only on size but also on shape, and will only be useful if the morphology is stable. In this work, we produce stable size-selected gold nanorods (aspect ratio 1-2) using a size-selected cluster source and correlate their luminescence behaviour with the particle shape. Thermodynamic modelling is used to predict the preferred aspect ratio of 1.5, in agreement with the observations, and confirms that the double-icosahedron observed in experiments is significantly lower in energy than the alternatives. Using these samples a fluorescence lifetime imaging microscopy study observed two photon luminescence from nanoparticle arrays and a fast decay process (<100 ps luminescence lifetime), which are similar to those found from ligand stabilized gold nanorods under the same measurement conditions, indicating that a surface plasmon enhanced two-photon excitation process is still active at these small sizes. By further reducing the nanoparticle size, this approach has the potential to investigate size-dependent luminescence behaviour at smaller sizes than has been possible before.     

Gold nanoparticles in biology: beyond toxicity to cellular imaging

Gold, enigmatically represented by the target-like design of its ancient alchemical symbol, has been considered a mystical material of great value for centuries. Nanoscale particles of gold now command a great deal of attention for biomedical applications. Depending on their size, shape, degree of aggregation, and local environment, gold nanoparticles can appear red, blue, or other colors. These visible colors reflect the underlying coherent oscillations of conduction-band electrons ("plasmons") upon irradiation with light of appropriate wavelengths. These plasmons underlie the intense absorption and elastic scattering of light, which in turn forms the basis for many biological sensing and imaging applications of gold nanoparticles. The brilliant elastic light-scattering properties of gold nanoparticles are sufficient to detect individual nanoparticles in a visible light microscope with approximately 10(2) nm spatial resolution. Despite the great excitement about the potential uses of gold nanoparticles for medical diagnostics, as tracers, and for other biological applications, researchers are increasingly aware that potential nanoparticle toxicity must be investigated before any in vivo applications of gold nanoparticles can move forward. In this Account, we illustrate the importance of surface chemistry and cell type for interpretation of nanoparticle cytotoxicity studies. We also describe a relatively unusual live cell application with gold nanorods. The light-scattering properties of gold nanoparticles, as imaged in dark-field optical microscopy, can be used to infer their positions in a living cell construct. Using this positional information, we can quantitatively measure the deformational mechanical fields associated with living cells as they push and pull on their local environment. The local mechanical environment experienced by cells is part of a complex feedback loop that influences cell metabolism, gene expression, and migration.     

基于相转化的金纳米棒表面修饰

利用种子生长法,以CTAB为表面活性剂制备的金纳米棒具有生物毒性.本研究利用相转化的方法修饰金纳米棒,修饰后金纳米棒的理化性质稳定,生物相容性更好,有更广的应用前景.     

Gold supported on thin oxide films: from single atoms to nanoparticles

[Figure: see text]. Historically, people have prized gold for its beauty and the durability that resulted from its chemical inertness. However, even the ancient Romans had noted that finely dispersed gold can give rise to particular optical phenomena. A decade ago, researchers found that highly dispersed gold supported on oxides exhibits high chemical activity in a number of reactions. These chemical and optical properties have recently prompted considerable interest in applications of nanodispersed gold. Despite their broad use, a microscopic understanding of these gold-metal oxide systems lags behind their application. Numerous studies are currently underway to understand why supported nanometer-sized gold particles show catalytic activity and to explore possible applications of their optical properties in photonics and biology. This Account focuses on a microscopic understanding of the gold-substrate interaction and its impact on the properties of the adsorbed gold. Our strategy uses model systems in which gold atoms and clusters are supported on well-ordered thin oxide films grown on metal single crystals. As a result, we can investigate the systems with the rigor of modern surface science techniques while incorporating some of the complexity found in technological applications. We use a variety of different experimental methods, namely, scanning probe techniques (scanning tunneling microscopy and spectroscopy, STM and STS), as well as infrared (IR), temperature-programmed desorption (TPD), and electron paramagnetic resonance (EPR) spectroscopy, to evaluate these interactions and combine these results with theoretical calculations. We examined the properties of supported gold with increasing complexity starting from single gold atoms to one- and two-dimensional clusters and three-dimensional particles. These investigations show that the binding of gold on oxide surfaces depends on the properties of the oxide, which leads to different electronic properties of the Au deposits. Changes in the electronic structure, namely, the charge state of Au atoms and clusters, can be induced by surface defects such as color centers. Interestingly, the film thickness can also serve as a parameter to alter the properties of Au. Thin MgO films (two to three monolayer thickness) stabilize negatively charged Au atoms and two-dimensional Au particles. In three dimensions, the properties of Au particles bigger than 2-3 nm in diameter are largely independent of the support. Smaller three-dimensional particles, however, showed differences based on the supporting oxide. Presumably, the oxide support stabilizes particular atomic configurations, charge states, or electronic properties of the ultrasmall Au aggregates, which are in turn responsible for this distinct chemical behavior.