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、光学特性、修饰及其在生物学中的应用

由于具有独特的光学和电子特性,金纳米棒受到人们越来越多的关注。金纳米棒的这些性质主要取决于它自身的形状、大小和长径比。尤其金纳米棒独特的、可调的表面等离子体共振特性,使其在生物标记、生物成像及生物医学等领域有非常广阔的应用前景。本论文详细介绍了金纳米棒的几种合成方法及其光学特性和金纳米棒的表面修饰手段,综述和比较了金纳米棒在生物分子探针技术、荧光探针和癌症诊断和光热治疗领域的研究进展,对其存在的问题做了具体分析并对金纳米棒在生物学中的应用方向进行了展望。     

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。     

晶种子生长法制备金纳米棒

发展绿色、高效、可控的制备方法来合成金纳米材料是纳米领域研究的热点,本文利用改良晶种子生长法制备了金纳米棒(Au NRs),对其形貌进行了表征。该方法具有简单、绿色等突出优点,对合成金纳米棒有一定的参考价值。     

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。     

软质纤维状纳米材料研究取得突破

<正>近日,中科院青岛生物能源与过程研究所的仿生智能材料团队在软质纤维状纳米材料方面有了新的研究进展。该课题组利用一种独特的蛋白质自组装结构——淀粉样纳米纤丝合成了边长接近半毫米的二维单晶金片。这种二维金单晶表面积超过104平方微米,厚度超过100纳米。该二维金单晶所具有的超过纳米尺度的几何形貌,对进一步拓展金单晶的应用空间具有重要价值。此外,这种肉眼可见的二维材料也可应用于光学及电子纳米器件、纳米天线1、传感和成像等领域。另外,通过与聚氨酯复合,他们制备了一种独特的柔性导电薄膜,具有应变应力传感行为。     

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。     

金纳米复合材料在催化环境污染物中的应用

金纳米作为贵金属纳米材料,在生物医学、传感、催化等领域都有广泛应用。尤其在催化领域,金纳米材料既可以催化偶氮染料、硝基化合物等水污染物,也可以催化CO、甲醛等空气污染物,是良好的环境污染物的催化剂。但是金纳米材料制作成本较高且溶液稳定性较差,需要与其他材料复合提高其催化应用性。因此,利用金纳米与其他材料复合形成新的金纳米复合材料用于催化环境污染物成为研究热点。     

金属纳米粒子修饰的碳纳米管研究进展

多壁和单壁碳纳米管（CNT）是被广泛研究的纳米材料之一,可以用作良好的金属或其它纳米粒子的载体。金属纳米粒子-碳纳米管复合材料在催化、传感、贮氢、及各种光学电学方面有广泛的应用前景,文章就近期各种碳纳米管负载的金属纳米材料（主要集中在贵金属）的合成做一小结。     

生物法介导纳米金合成研究进展

在纳米技术及纳米材料领域,既重要又具有挑战性的是金属纳米粒子的合成。纳米金作为金属纳米粒子中的一员,由于其具有独特的光学、电学和催化性质而在许多领域有着极其广泛的应用,因此,开发简单、经济、环境友好型的合成方法变得愈来愈重要,而控制特定尺寸、形状、结构将是一个巨大的挑战。综述了近年来利用生物法合成纳米金的进展,并对其将来的合成进行了展望。     

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.     

Induced pH-dependent shift by local surface plasmon resonance in functionalized gold nanorods

Localized surface plasmon resonance (LSPR) spectroscopy of metallic nanoparticles is a powerful tool for chemical and biological sensing experiments. In this study, we observed LSPR shifts of 11-mercaptoundecanoic acid modified gold nanorods (GNR-MUA) for the pH range of 6.41 to 8.88. We proposed a mechanism involving changes of the dipole moment after protonation/deprotonation carboxylic groups of 11-mercaptoundecanoic acid (MUA) which plays an important role by modulating LSPR around the functionalized GNR. Such a stable and easily prepared GNR-MUA has potential to become one of the most efficient and promising pH nanosensors to study intra- or extra-cellular pH in a wide range of chemical or biological systems.     

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.     

Mesoporous silica-coated gold nanorods: towards sensitive colorimetric sensing of ascorbic acid via target-induced silver overcoating

This article describes a nonaggregation-based colorimetric assay of ascorbic acid by tailoring the optical properties of mesoporous silica-coated gold nanorods (MS GNRs) via silver overcoating. The colorimetric measurement of ascorbic acid (AA) concentration strongly relies on the fact that the blue shift effect of localized surface plasmon resonance (LSPR) peak of MS GNRs is gradually enlarged with the increase of AA amount. The limit of detection is determined to be 49 nM, which is comparable to that of quantum dots (QDs)-based fluorimetric methods.     

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。     

Ultrahigh refractive index sensing performance of plasmonic quadrupole resonances in gold nanoparticles

The refractive index sensing properties of plasmonic resonances in gold nanoparticles (nanorods and nanobipyramids) are investigated through numerical simulations. We find that the quadruple resonance in both nanoparticles shows much higher sensing figure of merit (FOM) than its dipolar counterpart, which is attributed mainly to the reduction in resonance linewidth. More importantly, our results predict that at the same sensing wavelength, the sensing FOM of the quadrupole mode can be significantly boosted from 3.9 for gold nanorods to 7.4 for gold nanobipyramids due to the geometry-dependent resonance linewidth, revealing a useful strategy for optimizing the sensing performance of metal nanoparticles.     

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.     

Localized Surface Plasmon Resonance Biosensing with Large Area of Gold Nanoholes Fabricated by Nanosphere Lithography

Localized surface plasmon resonance (LSPR) has been extensively studied as potential chemical and biological sensing platform due to its high sensitivity to local refractive index change induced by molecule adsorbate. Previous experiments have demonstrated the LSPR generated by gold nanoholes and its biosensing. Here, we realize large uniform area of nanoholes on scale of cm² on glass substrate by nanosphere lithography which is essential for mass production. The morphology of the nanoholes is characterized using scanning electron microscope and atomic force microscope. The LSPR sensitivity of the nanoholes to local refractive index is measured to be 36 nm/RIU. However, the chip has demonstrated high sensitivity and specificity in biosensing: bovine serum albumin adsorption is detected with LSPR peak redshift of 27 nm, and biotin-streptavidin immunoassay renders a LSPR redshift of 11 nm. This work forms a foundation toward the cost-effective, high-throughput, reliable and robust chip-based LSPR biosensor.