两种不同光谱类型的R-藻红蛋白的荧光性质研究

红藻中的R-藻红蛋白(R-PE)依照其吸收光谱可分为两种不同的光谱类型,即“双峰型”和“三峰型”。本文通过对不同pH条件下的R-PE的荧光光谱及荧光寿命的研究,发现“三峰型”R-PE的pH稳定范围较“双峰型”R-PE大。在R-PE浓度对荧光光谱的影响实验中,随着蛋白浓度的增加,荧光峰位置逐渐红移。荧光寿命逐渐增大,荧光强度先行增加而后减弱。用碘离子对其荧光进行猝灭,随着碘离子浓度的增大,荧光强度逐渐降低,荧光寿命逐渐缩短,并服从Stem-Volmer规则。     

Correcting for Spectral Cross‐Talk in Dual‐Color Fluorescence Cross‐Correlation Spectroscopy

Dual‐color fluorescence cross‐correlation spectroscopy (dcFCCS) allows one to quantitatively assess the interactions of mobile molecules labeled with distinct fluorophores. The technique is widely applied to both reconstituted and live‐cell biological systems. A major drawback of dcFCCS is the risk of an artifactual false‐positive or overestimated cross‐correlation amplitude arising from spectral cross‐talk. Cross‐talk can be reduced or prevented by fast alternating excitation, but the technology is not easily implemented in standard commercial setups. An experimental strategy is devised that does not require specialized hardware and software for recognizing and correcting for cross‐talk in standard dcFCCS. The dependence of the cross‐talk on particle concentrations and brightnesses is quantitatively confirmed. Moreover, it is straightforward to quantitatively correct for cross‐talk using quickly accessible parameters, that is, the measured (apparent) fluorescence count rates and correlation amplitudes. Only the bleed‐through ratio needs to be determined in a calibration measurement. Finally, the limitations of cross‐talk correction and its influence on experimental error are explored.     

Laser-induced Fluorescence Spectroscopy of NiO between 510 and 650 nm

Laser-induced fluorescence excitation spectra of NiO have been recorded in the wavelength region of 510-650 nm under supersonic molecular beam conditions. More than fifty bands have been observed and rotationally analyzed to determine the molecular constants. The excited states exhibit highly irregular variations in terms of isotopic shifts, vibrational intervals, and rotational constants. Twenty-six bands attributed to [Ω=0, 1]-X3∑o transitions have been tentatively grouped into five vibrational progressions. Furthermore, dispersed fluorescence and lifetimes of the strong bands have also been measured.     

芳杂环推拉型大分子的多光子上转换荧光性质

用Wittig反应和Heck反应制备了2个新的芳杂环推-拉型荧光大分子聚[(2,5-二苯撑-1,3,4-噁二唑)-4,4'-乙烯撑-交替-N,N'-二(4-苯乙烯撑)]苯胺(P1)和聚[(2,5-二苯撑-1,3,4-噁二唑)-4,4'-乙烯撑-交替-N-乙基-3,6-咔唑乙烯撑](P2). P1和P2的分解温度分别为373和412 ℃, 热稳定性良好. 电化学性能用循环伏安法测定. P1和P2的最高占有分子轨道(HOMO)能级分别为-5.39和-5.81 eV, 最低未占有分子轨道(LUMO)能级分别为-2.81和-3.09 eV. 用飞秒Ti:Sapphire激光器测定了P1和P2的三光子和双光子上转换荧光光谱. 在1250 nm波长激发下, 在四氢呋喃溶液中P1和P2的三光子荧光发射峰分别位于510和491 nm. 在800 nm波长激发下, 在四氢呋喃溶液中P1和P2的双光子荧光发射峰分别位于511和495 nm. 在四氢呋喃溶液中大分子P1和P2单光子荧光发射峰分别位于503 和475 nm, P1和P2的荧光量子产率分别为0.80和0.31. 研究了多光子荧光发射过程的溶剂效应. 结果表明, 溶剂极性增大, P1和P2的多光子荧光发射波长明显红移.     

两种新型F-荧光化学传感器的合成及其性质研究

本文设计合成了N⁶-对甲苯磺酰胺腺嘌呤(I)和邻苯二对甲苯磺酰胺(Ⅱ)两种主体化合物.通过对其与阴离子物种之间相互作用的研究发现,它们在乙腈溶液中和Cl^-、Br^-、NO₃^-、NO₂^-、HSO₄^-、Ac^-、F^-几种阴离子相互作用时,仅对F^-具有专一的选择性识别作用.F^-离子可使I和Ⅱ主体的荧光吸收猝灭并发生红移.通过试验证明,F^-离子和I、Ⅱ主体的识别作用机理是因形成了激基缔合物.     

荧光共轭聚合物在生物大分子检测中的应用*

共轭聚合物因其具有π-电子体系及共轭离域结构,一般都具有优异的发光性能,其发光强度和发射波长会随被检测化合物结构的不同而发生特异性响应,特别是在与被检测物相互作用过程中所产生电荷和能量能够沿共轭分子链进行有效传递,成倍放大这种作用,从而有效提高了检测灵敏度,这比相应的小分子化合物更具有优越性。目前共轭聚合物已被用于开发新型化学、生物传感器,尤其是在生物分子检测方面的应用得到迅速的发展。本文总结了近年来荧光共轭聚合物在生物传感方面的研究进展,主要讨论共轭聚合物在蛋白质、核酸及毒素检测中的应用。     

Circumvention of fluorophore photobleaching in fluorescence fluctuation experiments: a beam scanning approach.

Photobleaching is a fluorophore-damaging process that commonly afflicts single-molecule fluorescence studies. It becomes an especially severe problem in fluorescence fluctuation experiments when studying slowly diffusing particles. One way to circumvent this problem is to use beam scanning to decrease the residence time of the fluorophores in the excitation volume. We report a systematic study of the effects of circular beam scanning on the photobleaching of fluorescent particles as observed in single-photon excitation fluorescence fluctuation experiments. We start by deriving a simple expression relating the average detected fluorescence to the photobleaching cross section of the fluorophores. We then perform numerical calculations of the spatial distribution of fluorescent particles in order to understand under which conditions beam scanning can prevent the formation of a photobleaching hole. To support these predictions, we show experimental results obtained for large unilamellar vesicles containing a small amount of the fluorescent lipophilic tracer DiD. We establish the required scanning radius and frequency range in order to obtain sufficient reduction of the photobleaching effect for that system. From the detected increase in fluorescence upon increase in scanning speed, we estimate the photobleaching cross section of DiD.     

含羧基中药成分荧光标记方法的建立及优化

用荧光标记技术对含羧基类中药成分进行标记,探索中药成分荧光标记方法,提高其检测灵敏度、为中药药代动力学研究奠定基础。以荧光试剂8-氨基芘-1,3,6-三磺酸三钠盐(APTS)和绿原酸组成研究体系,对标记条件进行优化。反应体系中加入1-乙基-3-(3-二甲氨丙基)碳二亚胺盐酸盐(EDC.HCl)与N-羟基丁二酰亚胺(NHS)可使衍生反应在室温下进行。APTS标记绿原酸的较优反应条件为:绿原酸与APTS的浓度比为1∶5,EDC的浓度为5 mmol/L,NHS的浓度为0.33 mmol/L。以0.1mol/L、pH5.50的NaH2PO4-Na2HPO4为缓冲溶液,绿原酸首先与EDC、NHS避光反应4 h,再与APTS反应4h,即可达到较好的标记效果。此标记方法操作简便,灵敏度高,可以用于含羧基类中药成分的荧光标记研究。     

The use of naphthalene fluorescence probes to study the binding sites on cyclodextrin polymers formed from reaction of cyclodextrin monomers with epichlorohydrin

Three naphthalene-based fluorescence probes were used as guest molecules to study host/guest binding with cyclodextrin (CD) polymer hosts prepared by treating -,-, or -cyclodextrin monomers with epichlorohydrin. The fluorescence data indicate that the binding interaction is much stronger for the probes with the CD polymers than with the CD monomers. Moreover, the fluorophore binding site on the CD polymers is also more hydrophobic than that on the CD monomers. Fluorescence lifetime data from one of the bound probes (2-(N-methylanilino) naphthalene-6-sulfonic acid) suggest that more than one type of binding site may exist on the CD polymers with this probe. A comparison of fluorescence data using different molecular weight ranges of the CD polymers appear to rule out the possibility of a 12 host/guest complex, where the two CD units come from the same polymer chain.     

中草药有效成分橙皮甙的固体表面延迟荧光法研究

本文以层析聚配角安膜为基质，用乙酸锂作增强剂，建立了测定痕量中草药有效成分橙皮甙的固体表面延荧光法。该法取样量少，线性范围宽，灵敏度高，操作简便快速。     

A simple light-emitted diode-induced fluorescence detector using optical fibers and a charged coupled device for direct and indirect capillary electrophoresis methods

We constructed a simple fluorescence detector for both direct and indirect CE methods using a blue light-emitted diode (470 nm) as excitation source, a bifurcated optical fiber as a waveguide, and a CCD camera as a detector. The connection of all the components is fairly easy even for nonexperts and the use of a CCD camera improves the applicability of this detector compared to the others using PMTs because it permits the recording of 2-D electropherograms or phosphorescence measurements. This detector provides a compact, low cost, and rapid system for the determination of native fluorescence compounds which have high quantum yields by CE with direct fluorescence detection, showing an LOD of 2.6 x 10(-6) M for fluorescein; the determination of fluorescence derivative compounds by CE with direct fluorescence detection, showing an LOD of 1.6 x 10(-7) M for FITC-labeled 1,6-diaminohexane; and nonfluorescence compounds by CE with indirect fluorescence detection with an LOD of 2.7 x 10(-6) M for gallic acid.     

可固定性荧光探针:线粒体成像的可靠工具

线粒体是一种具有双层膜结构的细胞器,参与细胞新陈代谢过程的能量循环以及离子平衡过程,在细胞生理过程中具有极其重要的意义。一些小分子荧光染料/探针结构中带有正电荷,因受到线粒体内膜负电势的牵引而标记在线粒体上,为研究线粒体的形态或功能提供了重要的可视化成像工具。然而,大多数线粒体染料/探针对线粒体的靶向标记稳定性仍不够理想,因为线粒体电势处于不断的动态变化中,当电势降低时,对染料的亲和力相应降低。尤其在病理条件下(比如细胞凋亡)细胞代谢受到阻滞时,线粒体膜电势显著降低,阳离子染料将扩散离开线粒体,造成非特异性荧光。最近,Kim团队和本人课题组提出可固定线粒体探针的新概念,用活性基团将荧光分子探针通过共价键固定在线粒体中,开发了稳定靶向线粒体中的定量探测微环境p H值、粘度、膜电势荧光探针。我们认为,对于追踪和探测具有高度动态变化特性的线粒体而言,开发可固定的线粒体荧光分子探针是必然趋势,因此本文进行评述和展望。     

Amphiphilic copolymers with pendant ­carbazolylalkyl groups. ­Effect of polymer structure on ­retardation of self‐quenching

A series of amphiphilic polyanions containing (9‐carbazolyl)alkyl methacrylamide or acrylamide were prepared and their fluorescence properties were compared in organic and aqueous solution. In organic solution, all copolymers exhibited a monomer emission which decayed exponentially, indicating no self‐quenching. Decreasing the length of the methylene spacer in the side chain induced the spectral broadening and sharpening, depending on the carbazolyl content in the copolymer. This may be related to the interchromophore interactions and the mobility of chromophores. In H ₂O, by contrast, quenched fluorescence was observed for the copolymers. It should be however noted that acrylamide‐type of amphiphilic copolymers, poly(9‐carbazolylmethyl‐acrylamide‐co‐sodium 2‐acrylamido‐2‐methylpropanesulfonate), are the least quenched polymers among those reported so far. Copyright © 2001 John Wiley & Sons, Ltd.     

实用型简易激光诱导荧光检测器的研制及性能测试

基于正交型结构,研制了一种简易实用的高效液相色谱激光诱导荧光检测器。以930荧光光度计为骨架,用岛津RF-535荧光检测池,配以自制可调稳压电源,分别以波长532am和405nm的自制激光器为激发光源,以罗丹明B和荧光素为荧光试剂评价体系的性能。罗丹明B的检出限为2．0×10^-8mol／L（S／N〉10）,荧光素的检出限为3．0×10^-10mol／L（S／N〉10）。测试结果表明该检测器达到了设计要求,具有足够的实用灵敏度和较宽的线性范围。     

The synthesis and fluorescence of a methoxy-phenyl substituted C_60-pyrrolidine derivative

A new 4-methoxyphenyl substituted C60-pyrrolidine derivative, C60(C10H13NO) (1), was prepared and its room-temperature fluorescence was studied. Its fluorescence intensity is three times stronger than that of C60. Its singlet energy was estimated to be 25 kJ/mol lower than that of C60. The fluorescence lifetime was determined to be 2.1+0.3 ns by using the frequency domain method. The fluorescence quenching by concentration and aromatic electron donor: N, N-dimethyl aniline (DMA) was investigated. Data show that its fluorescence could not be quenched by DMA.     

萘普生和酵母DNA相互作用的荧光光谱研究

使用紫外和荧光光谱法研究了萘普生和酵母DNA之间的相互作用。酵母DNA对萘普生的荧光存在强烈的猝灭作用，其作用方式随DNA浓度的变化而发生转变。用Stern-Volmer方程与Scatchard方程两种方法得到相同结果：在较低的DNA浓度下，萘普生与DNA间的作用较弱，而在较高DNA浓度时，萘普生与DNA的作用较强，键合位点数也随着酵母DNA浓度的升高而在临界酵母DNA浓度100 mmol/L附近出现转变。紫外光谱、离子强度的影响和I^-猝灭等研究表明，DNA浓度的变化并不改变两者间的作用方式，它们之间始终是一种沟槽作用模式。     

超痕量分析中的激光诱导荧光检测

本文对激光诱导荧光检测器(LIF-D)及其主要器件激光器、滤光片、透镜、光电检测器、荧光探针及扫描装置的现状和发展趋势作了综述,介绍了LIF在单分子检测中的应用.     

长白山白眉蝮蛇蛇毒磷脂酶A2的荧光光谱

利用荧光光谱系统研究了长白山白眉蝮蛇蛇毒磷脂酶Ａ２的荧光特性。研究结果表明：当发射波长与激发波长差为２０ｎｍ和７５ｎｍ时,ＰＬＡ２的同步荧光分别主要由酷氨酸（Ｔｙｒ）残基和色氨酸（Ｔｒｐ）残基所贡献。缓冲溶液的酸度变化能够明显影响ＰＬＡ２氨基酸侧链的电荷分布,从而改变ＰＬＡ２的荧光发射强度。了子Ｃａ＾２＋一方面能增强ＰＬＡ２的荧光强度,另一方面也能够加快ＰＬＡ２与底物二棕樟酰磷脂酰胆碱（ＤＰＰＣ）     

中氮茚腈类化合物的合成及其荧光性质的研究

合成了一系列中氮茚化合物,研究了化合物3a～3k,4a～4b,5～6分子中不同取代基对其荧光光谱和荧光量子效率的影响.发现中氮茚环上的氰基具有较好的荧光助色作用,中氮茚环上的COPh,COMe或CHO对分子的荧光具有猝灭作用;发现中氮茚类有机化合物的分子结构与荧光性质之间的某些关系.化合物3a～3b,3g～3i具有较高的荧光量子效率,可以作为比较好的有机荧光分子用于探针化合物的结构修饰.     

空间分辨荧光分析技术

空间分辨荧光分析技术突破了传统荧光分析的局限,为获得空间定位信息提供了技术保障。系统地综述了构成该技术的共焦荧光法、全内反射荧光法、多光子荧光法以及近场荧光法等4种方法的原理、特点、发展及其应用,并且强调了其在单分子测定中的作用。引用文献64篇。