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...     

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.     

银纳米簇在生物成像及生物检测中的研究进展

由于银纳米簇的尺寸接近电子的费米能级,其能级不连续而发生能带分裂。通过与光的相互作用,能级之间发生不连续的电子跃迁,使银纳米簇表现出强烈的荧光性质。银纳米簇凭借其易合成、荧光量子产率高、可调荧光发射波长(从可见光区到近红外区)、光稳定性和生物相容性良好等优势在生物成像及生物检测等领域引起了越来越多的关注。本文结合近年来关于银纳米簇的研究,详述了其在这两方面的以下几个部分的应用研究进展:DNA调控或标记的银纳米簇的生物成像、有其他金属掺杂的银纳米簇的生物成像、以蛋白为模板合成的银纳米簇的生物成像、利用银纳米簇的荧光特性对生物酶、蛋白、肽、氨基酸、基因、DNA、腺苷、细菌以及抗菌活性等的检测,并对银纳米簇的应用所面临的挑战和发展趋势进行了展望。     

纳米团簇的超分子自组装

在纳米材料的应用过程中, 纳米团簇或纳米粒子的组装将是非常关键的一步。纳米团簇的超分子化学组装方法可分为两类, 即胶态晶体法和模板法。胶态晶体法是利用胶体溶液的自组装特性将纳米团簇组装成超晶格, 可得到二维或三维有序的超晶格。模板法是利用纳米团簇与组装模板间的识别作用来带动团簇的组装, 可应用的模板有固体膜、单分子膜、有机分子、生物分子等。其中, 单分子膜模板是研究最多也是最为成熟的一种; 生物分子间严密的分子识别功能使其成为非常有发展前途的组装模板, 而且用生物分子模板有可能实现不同纳米团簇间的组装。     

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。     

金属纳米团簇(MNCs)的性能与应用*

金属纳米团簇(metal nanoclusters,MNCs)是由几个到几百个金属原子组成的内核被单层配体保护而形成的一类新型材料。MNCs的结构可在原子级精度的水平上进行调控,因其具有超小的尺寸、独特的电子能级以及大的比表面积等性质而获得了广泛的应用。主要基于ds区金属铜、银、金的纳米团簇 (CuNCs、AgNCs、AuNCs) 的相关研究介绍MNCs的概念、结构特征、主要性能、合成策略以及它们在催化、生物传感、生物成像和肿瘤治疗中的应用。     

Au25纳米团簇合成与应用研究进展

综述了新型金属纳米材料Au25纳米团簇的合成机理和合成工艺改进,结合Au纳米团簇荧光作用机理说明其特有的荧光特性,利用Au纳米团簇荧光性质在离子检测、生物小分子检测、蛋白质检测和生物成像方面的应用,为Au纳米团簇的研究提供参考。     

基于局域表面等离子体共振效应的光学生物传感器*

贵金属纳米粒子表现出许多常规块体材料所不具备的优异性能,其中局域表面等离子体共振 (LSPR) 特性是研究热点之一。LSPR 的形状和位置与纳米粒子的组成、大小、形状、介电性质以及局域介质环境密切相关。基于这一特性,贵金属纳米粒子已广泛应用于光学生物传感器、光过滤器和表面增强光谱等领域。本文对各种结构的贵金属纳米粒子的制备方法及其在光学生物传感器中的应用进行了综述,并对 LSPR 纳米传感器的未来发展前景做了展望。     

原子精确的金纳米团簇在催化中的配体效应

正金纳米团簇具有确定的组成和结构,作为模型化合物有助于理解物质结构与性能之间的关系。量子尺寸效应使金纳米团簇具有一些特殊的物理化学性质,因此在催化、生物、传感、光电等方面具有广泛的应用价值~(1,2)。目前国际上报道的结构确定的金纳米团簇主要包括硫醇、膦配体、炔配体以及混合配体保护的金纳米团簇~(3–7)。这些金纳米团簇可以作为模型催化剂来研究催化剂的结构与性能关     

基于金属纳米簇的荧光传感平台的最新研究进展

荧光纳米生物传感平台由于具有灵敏度高、选择性好、操作简单、成本低、实时监测等特点,吸引了广泛的关注。近年来,随着纳米技术的飞速发展,具有纳米结构的材料(纳米材料)在生物传感领域显示出独特的优势。与传统材料相比,纳米材料显示出独特的物化性质,如光学、电学、机械、催化和磁性等。金属(如Au、Ag、Cu及其合金)纳米簇(MNCs)是纳米科学和纳米技术领域中一种新颖的多功能纳米材料,其通常由几个到几十个金属原子组成,其核的尺寸通常小于2 nm。由于其发光能力强、易于合成和进行表面功能化、生物相容性好、尺寸超小、毒性低等优点,金属纳米簇在能源催化、医学诊断、电子器件、生物传感等领域得到了广泛的应用。此外,金属纳米簇的荧光性能极佳(如大的斯托克斯位移、可调节的荧光、高的光学稳定性和荧光量子产率等),因此被作为荧光纳米探针广泛应用于生物传感领域。该综述介绍了近年来基于不同构建机制的金属纳米簇基的传感平台的研究进展,及其在检测离子、生物分子、pH和温度传感等方面的应用。相信该综述能为从不同传感机理构建更具前景的生物传感器提供一些新见解和理论指导。     

A novel and sensitive method for recognition and indirect determination of Al(III) in biological fluid based on the quenching of resonance Rayleigh scattering intensities of "Al(III)-EV-DNA" complexing system

A novel method for recognition and indirect determination of Al(III) by using biological molecules has been established based on the quenching of RRS intensity. In the weak acidic medium, the reaction of ethyl violet (EV) and DNA would result in great enhancement of RRS intensity. However, the presence of Al(III) would lead to the decrease of the RRS intensity owing to the competition coordination of Al with DNA. The decreased intensity of RRS is directly proportional to the concentration of Al(III) in the range of (0.1-2.5)x10(-6) and (0.30-4.5)x10(-5)M, respectively. The method has high sensitivity and its detection limit (3sigma) is 3.6x10(-8)M. The characteristics of RRS spectra of the system, the optimum conditions of the reaction, and the reaction mechanism have been investigated. The method can recognize Al(III) selectively owing to its strong binding to the phosphate backbone of DNA, and has been applied to the determination of Al(III) concentration in synthetic biological samples with satisfactory results. Therefore, the proposed method is promising as an effective means for selective recognition and sensitive determination in situ of Al(III). Furthermore, this study would contribute to further understanding of the biological significance of Al neurotoxicity.     

A review of advances and new developments in the analysis of biological volatile organic compounds

Biological volatile organic compounds (VOCs) are interlinked to biological metabolism and bacterial populations localized on the surfaces of biological samples. The characteristics of biological VOCs at different physiological status or metabolism phases are various, which contain crucial bio-information. In this review, the significance of the study of biological VOCs was introduced, and crucial techniques greatly influencing the investigation were summarized and reviewed including efficient sampling, suitable analytical and bio-information distillation techniques. From the preliminary identification of biological VOC components to the interpretation of biological VOC characteristics is a great improvement in this field, which would provide more abundant bio-information during biological metabolism. Owing to complicated biological VOC compositions, any single sampling or bio-information distillation method could not obtain complete biological VOCs and interpret the biological VOC characteristics, and would result in the loss of effective bio-information. The combination of some suitable sampling and bio-information distillation techniques for the study of biological VOCs and the related bio-information will be a novel trend in the future.     

Lyophilised Platelet-Rich Fibrin: Physical and Biological Characterisation

Background: Platelet-rich fibrin (PRF) has gained popularity in craniofacial surgery, as it provides an excellent reservoir of autologous growth factors (GFs) that are essential for bone regeneration. However, the low elastic modulus, short-term clinical application, poor storage potential and limitations in emergency therapy use restrict its more widespread clinical application. This study fabricates lyophilised PRF (Ly-PRF), evaluates its physical and biological properties, and explores its application for craniofacial tissue engineering purposes. Material and methods: A lyophilisation method was applied, and the outcome was evaluated and compared with traditionally prepared PRF. We investigated how lyophilisation affected PRF’s physical characteristics and biological properties by determining: (1) the physical and morphological architecture of Ly-PRF using SEM, and (2) the kinetic release of PDGF-AB using ELISA. Results: Ly-PRF exhibited a dense and homogeneous interconnected 3D fibrin network. Moreover, clusters of morphologically consistent cells of platelets and leukocytes were apparent within Ly-PRF, along with evidence of PDGF-AB release in accordance with previously reports. Conclusions: The protocol established in this study for Ly-PRF preparation demonstrated versatility, and provides a biomaterial with growth factor release for potential use as a craniofacial bioscaffold.     

The first synthesis of an epidiselenodiketopiperazine

Epidithiodiketopiperazines (ETPs) are natural products (e.g., gliotoxin) with varied and important biological activity, which often is attributed to the redox properties of the disulfide moiety. As such, analogs with altered redox properties and similar structural characteristics would be of value to biological investigations. The use of an ETP as the point of departure in the first synthesis of an epidiselenodiketopiperazine (ESeP) and its activity against Mycobacterium tuberculosis (MTB) is reported.     

纳米金属有机骨架材料及其载药应用

金属有机骨架材料(MOFs)是指由含氮、氧等多齿有机配体与金属离子通过自组装形成的配位聚合物。由于金属有机骨架材料的大比表面积和高孔隙率等优点使其在药物负载领域有广泛应用。近年来,纳米金属有机骨架材料(NMOFs)因既具有MOFs的特点,又具有纳米材料独特的理化性能,使其兼具药物负载量高、目标靶向性好、表面易改性和生物相容性优良等特点,已成为一种优异的纳米级载药系统。本文介绍了NMOFs的常用制备方法,主要包括溶剂热法、反相微乳液法与超声波法,并对其优缺点进行了讨论;详细阐述了载药NMOFs的特性及其不同类型对于各类药物的负载能力;指出今后其主要的研究方向是改善生物相容性、实现更有效的表面功能化、扩展生物NMOFs及其负载药物的种类,使其应用到更多疾病的治疗上。     

Probing cell chemistry with time-of-flight secondary ion mass spectrometry: development and exploitation of instrumentation for studies of frozen-hydrated biological material

Imaging static secondary ion mass spectrometry (SIMS) offers a powerful method of obtaining molecular information from biological systems with good spatial resolution. However, the technique needs further development to make it suitable for routine analysis of cells. We report here the development of a new freeze-facture device to facilitate the manipulation and analysis of biological cell material, with the cell chemistry preserved intact by rapid freezing. We illustrate performance characteristics with high-contrast images of freeze-fractured, frozen-hydrated liposomes with the drug clofazamine constrained within the lipid bilayer providing a marker to determine the fracture plane across the liposome structure. By monitoring and imaging clofazamine on the surface of yeast cells in the frozen-hydrated state, and demonstrating its absence within molecular information from a cell fractured to reveal the cell ultrastructure, we demonstrate that the molecule does not penetrate the cell wall.     

Spectral-isotopic method of determination of gas-forming elements in organic and inorganic substances

A review is given of the latest papers on the application of the spectral-isotopic method of determination of gas-forming impurities in organic and inorganic materials. Main attention is paid to a new kind of investigation, i.e. the development of spectroscopic methods for isotopic analyses of nitrogen, carbon, oxygen, and hydrogen in biological objects for use in analytical monitoring in biological experiments with “tracers”. A universal method is described for the preparation of natural samples, for the separation of the gases to be analyzed from the sample, and for their purification from the impurities. The main characteristics are given of the methods for individual determination of the above elements and for joint analyses of some elements (N¹⁵-C¹³-H²) in one analytical cycle (spectrum excitation conditions, isotope concentration calculations, etc.). The characteristics of the methods have been compared with the results of other researches and the scope of our method for applications in biological investigations with tracers has been defined. The main results of spectral-isotopic method development in the traditional direction, i.e. for quantitative analysis of impurities in solid inorganic materials and for gas analysis, are produced.     

LC Method for the Determination of NPC1161, Primaquine and their Metabolites in Various Biological Systems

NPC1161 is an 8-aminoquinoline anti-malarial analog, which has a favorable toxicity profile relative to primaquine and other 8-aminoquinolines. High-performance liquid chromatographic method was developed for the determination of NPC1161, primaquine and their metabolites in biological samples in order to facilitate metabolic and pharmacokinetic studies. The method includes extraction of the unchanged drugs and their metabolites from the biological samples. Separation was achieved by reversed-phase chromatography on a C18 column with water–acetonitrile both containing 0.025% trifluoroacetic acid as the mobile phase. Recoveries of NPC1161 and its metabolites were greater than 60% in various biological samples tested. No interference with the components of the biological material was observed. The detector response was linear with concentrations of NPC1161 and its metabolites (desalkyl NPC1161 and carboxy NPC1161) in the ranges from 0.5 to 80.0, 0.4–60.0 and 0.4–70.0 μg mL⁻¹, respectively. A mass spectrometry coupled with electrospray ionization (ESI) interface method is described for the identification of NPC1161 and its metabolites in biological samples. This method involved the use of the [M + H]⁺ions of NPC1161, C3 analog (internal std. for the assay), desalkyl NPC1161 and carboxy NPC1161 at m/z 434, 406, 349 and 449 in the positive ion mode with extractive ion monitoring (EIM). This method will have an important application in pharmacokinetic studies of NPC1161 and in understanding the mechanism of metabolism of this novel 8-aminoquinoline analog in more detail.     

解吸电喷雾电离技术

本文介绍了一种新近发展起来的质谱离子化方法——解吸电喷雾电离（desorption electrospray ionization, DESI）及其最新研究进展。该方法首次于2004年提出后,由于其具有样品无需前处理就可以在常压条件下从各种载物表面直接分析固相,或凝固相样品等优势而得到了迅速的发展。本文描述了DESI的基本原理、离子源的结构和相关优化的参数,并对该离子化方法中所用的载物表面进行了总结。在实际应用方面,本文综述了DESI技术在常压气相化学反应产物监测,合成高聚物表征,爆炸物和化学战毒剂检测,以及在药品,生物代谢产物和生物组织表面分析方面的应用成果,同时对DESI的基础应用研究方向进行了分析和展望。     

体液中铝形态的HPLC分析

体液中铝浓度的升高能够导致严重的神经性疾病如阿尔茨海默症和帕金森氏症等。铝的毒性及生物效应与其存在形式有关,因此迫切需要建立可靠的分析体液中实际铝形态的方法。近十年来各种分离模式的HPLC在这方面使用最多。实验证明,血清中的铝主要与转铁蛋白(Tf)以AlN-Tf和AlN-Tf-Fec的方式结合,而余下的部分则与柠檬酸(Citrate)、磷酸(Phosphate)形成Al-citrate,Al-phosphate和Al-citrate-phosphate。