荧光金纳米团簇在小分子化合物检测中的应用

金纳米团簇(gold nanoclusters,Au NCs)是一种新型的荧光纳米材料,由几个到几百个原子组成,尺寸接近于电子的费米波长。由于量子尺寸效应,金纳米团簇显示出独特的光学特性。荧光金纳米团簇具有尺寸小、水溶性好、光物理性质好、比表面积大、表面易于修饰以及荧光性质随尺寸可调等优点,是近年来的研究热点。通过改变配体或者生物支架合成的各种荧光金纳米团簇,在传感检测、纳米标记、医学成像和光电子学等领域具有潜在的应用前景。作为新型荧光探针,荧光金纳米团簇已成功用于对阳离子、阴离子及重要的生物活性物质如过氧化氢、葡萄糖、谷胱甘肽、三磷酸腺苷、氨基酸等小分子化合物的检测。本文结合当前的研究现状,介绍了金纳米团簇在小分子化合物荧光检测中的应用,并简要评述了金纳米团簇研究中所面临的挑战及应用前景。     

金团簇的荧光性质及其生物应用

金纳米团簇作为一类新型纳米材料具有独特的光学特性。当金纳米团簇颗粒的尺寸小到与电子的费米波长（〈1nm）相当时,由于量子尺寸效应,金颗粒会受激发射出荧光。作为一种新型荧光材料,金纳米团簇具有发光颜色随团簇尺寸可调、荧光不易猝灭等许多优势。本文主要综述了金纳米团簇的荧光性质及其在生物标记、生物成像以及生物检测等方面的应用...     

牛血清白蛋白介导合成的金纳米簇用于活细胞荧光成像

以牛血清白蛋白介导合成金纳米簇, 并利用荧光分光光度计、纳米粒度及zeta电位仪以及非变性聚丙烯酰胺蛋白质电泳对其进行了表征. 结果表明, 该金纳米簇不仅荧光信号较强, 而且在不同pH值溶液中荧光稳定性好. 在此基础上进一步考察了金纳米簇与宫颈癌细胞(HeLa)间的相互作用. 结果表明, 该金纳米簇可成功进入活细胞内, 在最佳的培育时间和金纳米簇浓度条件下可达到较好的活细胞荧光标记效果, 且在经过细胞固定化处理后仍保持其标记形态.     

基于蛋白和多肽为模板的贵金属纳米簇合成研究

贵金属(Au, Ag, Pt等)纳米簇通常指的是由几个到约一百个原子组成的分子聚集体, 具有生物相容性好、超小尺寸(<2 nm)以及优异的物理化学性质, 尤其是能发出较强荧光等特点引起了人们的广泛关注. 目前多种贵金属纳米簇的合成方法已相继被报道, 且已应用于生物荧光成像、电化学发光、生物传感器以及细胞标记等多个领域. 本文共分为五部分, 首先重点介绍近几年兴起的以蛋白和多肽为模板来合成纳米簇的方法及优点, 并随后总结列举了文献中所采用的蛋白以及自主设计的多肽组分序列的类别, 随后探索了蛋白和多肽中的特定氨基酸与合成的贵金属纳米簇的荧光波长、量子产率、粒径之间的联系. 本文最后总结阐述了蛋白和多肽为模板成功合成贵金属纳米簇的先决条件并对其生物医学应用前景进行了展望.     

金纳米棒——从可控制备与修饰到纳米生物学与生物医学应用

金纳米棒因其独特的光学活性(纵向和横向两个等离子体共振吸收峰,可调范围从可见光区到近红外区)、长径比可调,表面易于修饰,生物相容性良好而使得其在纳米生物学和生物医学等领域具有广泛的应用前景。金纳米棒的合成及表面修饰直接决定着其物理化学性质,进而影响其生物相容性及其在生物医学中的应用。本文综述了金纳米棒的可控制备方法(包括模板法、电化学法、光化学法和晶种法)、表面可控修饰方法及其在纳米生物学和生物医学中的应用新进展,重点总结了金纳米棒的表面可控修饰及其在分子探针、生物传感、生物成像、药物载体、基因载体和光热疗法的最新研究进展。最后针对金纳米棒在生物应用过程中的一些瓶颈问题(如:特异性识别能力需要增强和荧光量子产率尚待提高等)提出了将手性分子或智能聚合物引入到金纳米棒表面进行可控修饰,以期增强其特异性识别能力并提高荧光量子产率,为金纳米棒的发展提供了新的思路。     

铜纳米簇的制备、聚集诱导荧光增强性能及应用研究进展

铜纳米簇不仅具有金属纳米簇的特异性,还有前驱体价格便宜等优点,因此有广泛的应用前景。从配体辅助法、模板法、微波法、电化学法和刻蚀法等综述了铜纳米簇的制备方法。从离子诱导聚集、pH诱导聚集、组装诱导聚集和溶剂诱导聚集增强发射等方面综述了铜纳米簇聚集诱导荧光发射增强性能。从离子检测、小分子检测、酶活性检测、生物大分子检测和生物成像等方面综述了铜纳米簇的应用,并对铜纳米簇的制备、性能优化和应用等方面作了展望。     

金纳米棒的光学性质研究进展

金纳米棒在紫外-可见-近红外(UV-Vis-NIR)波段具有独特的可调节表面等离子体共振(SPR)光学特性,其良好的稳定性、低生物毒性、亮丽的色彩和在催化、信息存储、生物医学等领域广阔的应用前景受到相关研究领域的广泛关注.结合已有的研究基础,本文主要综述了金纳米棒光学性质的研究进展,包括表面等离子体共振、局域场增强效应、共振耦合效应及荧光特性,并对金纳米棒的应用做了展望.     

超小金纳米簇用于荧光及CT双模态成像的研究

基于金纳米簇强烈的量子限制效应（strong quantum confinement effect,SQCE）,采用一步合成法,制备了同时具有高效近红外荧光与CT双模态成像能力的超小金纳米簇.实验表明,通过优化合成比例以及合成条件,所合成的超小金纳米簇具有很大的斯托克斯（Stokes）位移、较高的荧光强度和X射线吸收效率.除此之外,该超小金纳米簇具有良好的单分散性、稳定性和生物相容性.4T1肿瘤细胞荧光成像实验结果表明,该纳米粒子可被肿瘤细胞快速、高效地摄取.     

手性金纳米团簇:一种新型近红外荧光探针

近红外荧光成像具有低背景荧光干扰、强组织穿透力和对生物机体无光损伤等优点, 因此发展具有良好生物相容性、量子产率高、化学及光稳定性好的水溶性长波段近红外荧光探针成为目前的研究热点. 与有机近红外荧光染料相比, 无机纳米近红外荧光探针因其具有较高的摩尔消光吸光系数和荧光量子产率、抗光漂白能力强、发射光谱集中且可调等特点而备受重视. 采用N-异丁酰基-L(D)-半胱氨酸(N-isobutyryl-L(D)-cysteine, L(D)-NIBC)手性对映异构体作为还原剂和稳定剂一步法直接制备得到两种平均粒径小于2 nm的水溶性手性金纳米团簇(L-NIBC-AuNCs和D-NIBC-AuNCs). CD光谱显示二者在230~360 nm波段的圆二色性完美对称, 荧光光谱显示二者均在900~1000 nm的近红外波段具有较强的荧光发射峰, 且二者的荧光量子产率分别达到6.9% (L-NIBC-AuNCs)和8.2% (D-NIBC-AuNCs), 细胞毒性实验表明这两种手性金纳米团簇均无细胞毒性. 上述结果表明两种手性金纳米团簇不仅符合成为近红外荧光探针的基本要求, 而且还具有不对称光学活性和潜在的手性识别能力等独特性质. 手性金纳米团簇具有成为一类全新的近红外荧光探针的潜力, 为将来实现对特定分子通过手性识别来进行体内近红外荧光示踪和成像提供了全新的思路.     

金纳米颗粒制备及应用研究进展

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。     

Cytidine-stabilized gold nanocluster as a fluorescence turn-on and turn-off probe for dual functional detection of Ag and Hg

In this study, we have developed a label-free, dual functional detection strategy for highly selective and sensitive determination of aqueous Ag⁺ and Hg²⁺ by using cytidine stabilized Au NCs and AuAg NCs as fluorescent turn-on and turn off probes, respectively. The Au NCs and AuAg NCs showed a remarkably rapid response and high selectivity for Ag⁺ and Hg²⁺ over other metal ions, and relevant detection limit of Ag⁺ and Hg²⁺ is ca. 10 nM and 30 nM, respectively. Importantly, the fluorescence enhanced Au NCs by doping Ag⁺ can be conveniently reusable for the detection of Hg²⁺ based on the corresponding fluorescence quenching. The sensing mechanism was based on the high-affinity metallophilic Hg²⁺–Ag⁺ interaction, which effectively quenched the fluorescence of AuAg NCs. Furthermore, these fluorescent nanoprobes could be readily applied to Ag⁺ and Hg²⁺ detection in environmental water samples, indicating their possibility to be utilized as a convenient, dual functional, rapid response, and label-free fluorescence sensor for related environmental and health monitoring.     

A label-free and sensitive fluorescent assay for one step detection of protein kinase activity and inhibition

In this paper, a label-free, highly sensitive and simple assay for one step detection of protein kinase (PKA) activity and inhibition that avoids the fluorescent dye process has been established. The detection was based on the fluorescence (FL) quenching of peptide-Ag nanoclusters (Ag NCs) caused by antibody modified Au nanoparticles (anti-Au NPs) via fluorescence resonance energy transfer (FRET). With PKA and adenosine 5′-triphosphate (ATP) introduced, the substrate peptide of Ag NCs could react with PKA via targeted phosphorylation, and followed by the linking interactions between peptide-Ag NCs and anti-Au NPs. According to the fluorescence quenching of Ag NCs, the activity of protein kinase can be facilely monitored in the range of 0.1–2000 mU/μL with high sensitivity. The detection limit for PKA is 0.039 mU/μL. We further explored the inhibitory effect of H-89 for protein kinase activity. The developed method was also applied to the investigation of drug-induced PKA activation in HeLa cells, which provides a promising means for screening of kinase-related drugs and the clinical diagnosis of disease.     

Metal‐Enhanced Fluorescence of CdTe Nanocrystals in Aqueous Solution

Metal‐enhanced fluorescence of semiconductor nanocrystals (NCs) is investigated. There is very little attention paid to the metal‐enhanced fluorescence in aqueous solution, which has great potential applications in bioscience. In this work, we directly observe metal‐enhanced fluorescence of CdTe NC solution by simply mixing CdTe NCs and Au nanoparticles, both of which are negatively charged. In order to study this kind of photoluminescence enhancement in aqueous solutions, we propose a calibration method, which takes into account the light attenuation in solutions. After consideration of the light weakening in transmission, the maximal PL enhancement is about 3 times as large as the ones without Au NPs. Some factors related to the enhanced magnitude of fluorescence, for instance, the concentration and the molar feed ratio of CdTe NCs and Au NPs, are studied in detail. Furthermore, the decreased lifetimes of CdTe NCs induced by Au NPs are also obtained, which are in accord with the enhancement of the photoluminescence.     

High‐Level Incorporation of Silver in Gold Nanoclusters: Fluorescence Redshift upon Interaction with Hydrogen Peroxide and Fluorescence Enhancement with Herbicide

High‐level incorporation of Ag in Au nanoclusters (NCs) is conveniently achieved by controlling the concentration of Ag⁺ in the synthesis of bovine serum albumin (BSA)‐protected Au NCs, and the resulting structure is determined to be bimetallic Ag₂₈Au₁₀‐BSA NCs through a series of characterizations including energy‐dispersive X‐ray spectroscopy, mass spectroscopy, and X‐ray photoelectron spectroscopy, together with density functional theory simulations. Interestingly, the Ag₂₈Au₁₀ NCs exhibit a significant fluorescence redshift rather than quenching upon interaction with hydrogen peroxide, providing a new approach to the detection of hydrogen peroxide through direct comparison of their fluorescence peaks. Furthermore, the Ag₂₈Au₁₀ NCs are also used for the sensitive and selective detection of herbicide through fluorescence enhancement. The detection limit for herbicide (0.1 nm ) is far below the health value established by the U.S. Environmental Protection Agency; such sensitive detection was not achieved by using AuAg NCs with low‐level incorporation of Ag or by using the individual metal NCs.     

Ni(2+)-modified gold nanoclusters for fluorescence turn-on detection of histidine in biological fluids

In this work, Ni(2+)-modified gold nanoclusters were fabricated for fluorescence turn-on detection of histidine. The fluorescence of Au NCs was first quenched by Ni(2+). Then, the addition of histidine can restore the fluorescence of Au NCs by binding with Ni(2+) and removing it from the surface of the Au NCs. This architecture ensured non-toxic, cost-effective, label-free and sensitive detection of histidine. The developed Au NCs-based fluorescent sensor offered high selectivity for histidine over other amino acids. The relative standard deviation (RSD) for eleven replicate detections was 2.7%. The detection limit for histidine is 30 nM. The recovery of spiked histidine in human urine samples ranges from 95 to 104%.     

Cancer Cell Imaging Using in Situ Generated Gold Nanoclusters

In situ generated fluorescent gold nanoclusters (Au‐NCs) are used for bio‐imaging of three human cancer cells, namely, lung (A549), breast (MCF7), and colon (HCT116), by confocal microscopy. The amount of Au‐NCs in non‐cancer cells (WI38 and MCF10A) is 20–40 times less than those in the corresponding cancer cells. The presence of a larger amount of glutathione (GSH) capped Au‐NCs in the cancer cell is ascribed to a higher glutathione level in cancer cells. The Au‐NCs exhibit fluorescence maxima at 490–530 nm inside the cancer cells. The fluorescence maxima and matrix‐assisted laser desorption ionization (MALDI) mass spectrometry suggest that the fluorescent Au‐NCs consist of GSH capped clusters with a core structure (Au_8‐13). Time‐resolved confocal microscopy indicates a nanosecond (1–3 ns) lifetime of the Au‐NCs inside the cells. This rules out the formation of aggregated Au–thiolate complexes, which typically exhibit microsecond (≈1000 ns) lifetimes. Fluorescence correlation spectroscopy (FCS) in live cells indicates that the size of the Au‐NCs is ≈1–2 nm. For in situ generation, we used a conjugate consisting of a room‐temperature ionic liquid (RTIL, [pmim][Br]) and HAuCl₄. Cytotoxicity studies indicate that the conjugate, [pmim][AuCl₄], is non‐toxic for both cancer and non‐cancer cells.     

Uptake and imaging of glycine functionalized gold nanoclusters in Spodoptera frugiperda (Sf9) cells

Journal of Cluster Science - Fluorescent gold nanoclusters (Au NCs) have attracted considerable interest in biological application. Here, we reported a novel Au NCs with blue fluorescence,...     

11-Mercaptoundecanoic acid functionalized gold nanoclusters as fluorescent probes for the sensitive detection of Cu2+ and Fe3+ ions

Metal ions are physiologically essential,but excessive metal ions may cause severe risk to plants and animals.Here,we prepared gold nanoclusters(Au NCs) protected by 11-mercaptoundecanoic acid(11-MUA),which have excellent fluorescence properties for the detection of metal ions.The results showed that the copper ions(Cu~(2+)) and iron ions(Fe~(3+)) in the solution have obvious quenching effect on the fluorescence intensity of Au NCs.The detection range of Fe~(3+) was 0.8–4.5 mmol/L(R~2= 0.992) and 4.5–11.0 mmol/L(R~2= 0.997).And Cu~(2+) has a lower linear range(0.1–1.0 mmol/L,R2= 0.993).When EDTA was added into the reaction system,it was observed that the quenching effect of Cu~(2+) and Fe~(3+)on Au NCs showed different phenomenon.Then,the effect of metal ions on the fluorescence of Au NCs was investigated.The selective detection of Cu~(2+) was achieved by EDTA masking of Fe~(3+).In addition,we realized the metal ions detection application of Au NCs in the serum     

以DNA为模板的银纳米簇荧光检测及逻辑门的构建

以DNA为模板, 合成了具有荧光性质的银纳米簇(DNA-Ag NCs), 利用荧光光谱、 紫外光谱和红外光谱等手段对其进行了表征. 基于DNA-Ag NCs与离子相互作用时产生的荧光变化可实现对离子浓度的检测. 实验结果表明, 在最佳实验条件下, Ni ²⁺及Hg ²⁺的浓度与DNA-Ag NCs荧光强度呈线性关系; 并验证了该荧光探针用于检测自来水样品中汞离子和镍离子的实用性. 由于以DNA为模板的DNA-Ag NCs能够响应多种刺激, 如Ni ²⁺, S ^2-, Hg ²⁺和pH等, 利用相应的荧光强度可构建多输入的DNA-Ag NCs逻辑门及其组合逻辑门. 当荧光输出强度(I_output)>初始荧光强度(I_origin)时, 设定输出为1, 采用各种刺激及其组合作为输入, 构建了YES, INH和组合的NOR与INH逻辑门. 而只有当I_output≥I_origin时定义为输出为1, 可建立NOT, NOR, 组合的IMP加上NOR与AND逻辑门. 基于DNA-Ag NCs可以构建响应多元输入的复杂逻辑门, 实现化学信息的转变和传输, 在构建新的分子器件方面有较大应用前景.     

脯氨酸保护的铜纳米团簇的制备及其在三硝基苯酚检测中的应用

以脯氨酸(Pro)为保护剂,盐酸羟胺为还原剂,通过一步化学还原法制备脯氨酸稳定的铜纳米团簇(Cu NCs).采用分子荧光仪和紫外可见吸收仪对Cu NCs的光学性质进行分析,通过透射电子显微镜(TEM)、X射线光电子能谱(XPS)和傅里叶变换红外波谱仪(FTIR)对Cu NCs的结构进行表征.TEM图像显示Cu NCs的...