环糊精衍生物及包合物构建荧光探针的研究进展

环糊精是超分子化学中的一类重要主体化合物,在药物缓释、化学传感、对映体分离以及新型材料等众多领域都得到了广泛的应用.由于环糊精具有外亲水内疏水的桶形结构,其空腔内可以插入具有识别功能的受体分子或荧光染料,可通过螯合或置换方式实现对目标分子的识别,因此基于环糊精衍生物及包合物构建荧光探针也受到了人们的极大关注.总结了基于环糊精设计合成的荧光探针在检测金属离子、阴离子和分子等方面的应用,重点描述了识别性能和识别机制,为环糊精衍生物及包合物在荧光检测领域的应用提供理论依据.     

基于DPA识别基团的锌离子荧光传感器

锌离子在生物体系中扮演着重要角色,其分析和检测在疾病诊断和医疗检测等方面具有重要价值。用于 Zn²⁺ 检测的荧光传感器具有检测方便、灵敏度高等优点,引起了广泛关注。典型的荧光传感器通常是由识别基团和作为报告单元的荧光团通过间隔基团或直接连接而组成的。识别基团是荧光传感器的作用核心,在高选择性识别过程中起着至关重要的作用。自 1996 年第一次接在荧光素上以来,DPA (N,N-二(2-吡啶甲基)胺, di-2-picolylamine) 基团在锌离子传感器的设计中得到了广泛应用。本文综述了近年来文献中报道的基于 DPA 识别基团的锌离子传感器,介绍了锌离子荧光传感器的合成方法与识别原理,最后简单介绍了锌离子传感器中其它几种常见的识别基团。     

金属离子响应型荧光传感分子的设计原理及研究进展

荧光传感凭借其高灵敏度、可实现远程监测和实时性等优越性而广受关注,在离子识别中常被用于离子识别信号的输出.随着主客体化学的迅速发展,许多具有良好性能的离子响应型荧光探针相继被报道,从分子内电荷转移(ICT)、光诱导的电子转移(PET)、荧光共振能量转移(FRET)、激发态分子内质子转移(ESIPT)、激基缔合物的生成/消失、螯合作用导致的荧光增强(CHEF)等不同机理对荧光传感型离子识别受体的设计思路进行了理论阐释,归纳总结了近5年来相关文献报道,阐述了其研究现状和研究进展,并展望了该领域的研究方向.     

5,5-二乙烯基-2,2-联吡啶:可能的新型锌离子荧光探针(英文)

生物体系里微量元素锌在发育、新陈代谢和疾病的发生等多个领域扮演了重要的角色,定性和定量测量锌的含量将帮助我们理解锌的生物学意义。我们偶然发现5,5-二乙烯基-2,2-联吡啶(DVBP)在二氧六环里对锌离子呈现出类似比例计量型荧光探针的特性:即有2个荧光发射峰而且长波长峰随锌离子的增加按比例增长。但DVBP难溶于水而且2个荧光发射峰距离太近从而相互干扰,我们尝试利用硅氢反应将DVBP固定在多孔硅上制备感应锌离子的光极,我们发现多孔硅固相载体上的联吡啶通过与锌离子的螯合后荧光增强约8倍,比DVBP在溶液里与锌离子螯合后的荧光增强(约4.5倍)还要多,联吡啶对锌离子的荧光响应是一个值得继续探索的领域。     

钯离子荧光探针的研究进展

钯是一种重要的贵金属,在制药、燃料电池、电子电气和珠宝等行业得到广泛的应用。 然而,它的大量使用不可避免会造成其在环境中的残留,产生毒害,因此对钯的检测与识别具有重要的意义。 荧光探针具有较高的选择性、较高灵敏度、对设备依赖小、操作简单、检测限低等优点。 本文综述了近年应用于低浓度检测钯离子荧光分子探针的设计方法及作用机制。 按照荧光探针检测钯离子的响应模式,主要分为淬灭型、增强型、比率型3种方式进行评述。 尽管钯离子探针的研究在分子设计上取得了重要进展,但荧光染料与钯离子的响应时间尚且不能人为控制,尤其对于复杂体系中钯离子的检测效果尚待进一步改进。 因此,开发钯离子响应时间短、灵敏度高、专一识别性高并能应用于复杂体系的荧光探针,可能是今后主要发展方向。     

基于小分子的铜离子与汞离子双识别荧光探针

铜离子在不同细胞生理过程中作为催化辅助因子起着很重要的作用,但是体内铜离子浓度出现异常也会导致疾病甚至死亡。与铜离子相比,汞离子是各种重金属污染物中最普遍、最危险的一种。因此,对它们高灵敏度、高选择性检测具有非常重要的意义。荧光探针法由于具有灵敏度高、快速便捷、可视化和原位无损检测等优点而成为Cu²⁺与Hg²⁺离子重要的检测手段之一。本文总结了近几年基于小分子Cu²⁺和Hg²⁺离子双识别荧光探针的设计合成、性能及其在分析方面的研究与最新进展,并展望了此类荧光探针未来的研究与发展方向。     

萘酰亚胺类荧光分子探针的研究进展

荧光分子探针作为一种有效的金属离子检测手段,不仅使用方便,而且具有高灵敏度,高选择性等突出的优点.作者综述了萘酰亚胺类荧光分子探针的最新研究进展;指出萘酰亚胺化合物具有独特的荧光化学性质(如荧光量子产率高、荧光发射波长适中、斯托克斯位移大、光稳定性好、结构易于修饰等),因此被广泛应用于荧光探针研究领域,并且在合成、离子识别、检测及细胞成像等方面不断取得新的应用.     

一种具有聚集荧光增强性质苯并咪唑化合物的合成及其对Zn2+的识别

利用5-甲基水杨醛和2-氨基苯并咪唑合成了一种结构简单的席夫碱荧光探针L,通过氢谱和碳谱表征了其结构。在乙醇-水混合溶液中对其进行了聚集荧光性能的测试,结果表明在混合体系下,随着水含量的升高探针L的荧光强度逐渐增强,表明探针L具有AIE性质。在乙醇体系中,L对锌离子具有高选择性识别,表现出明显的荧光增强,检测限可达到4.11×10~(-6 )M,表明了探针L对锌离子的检测有较高的灵敏度。     

铜离子荧光探针的研究进展

高选择性、超灵敏性铜离子荧光探针的设计和开发,在环境检测、食品安全及人体内微量铜元素探测等领域具有重要意义。本文根据荧光分子探针对铜离子的识别机制和化学结构特点,从罗丹明、香豆素、芘基团、萘酰亚胺、氟硼吡咯及其他荧光基团等发色团出发,综述了近年来铜离子荧光探针的研究进展。参考文献27篇。     

一种基于铜配合物的高灵敏硫化氢荧光探针

作为继NO和CO之后的第三个气体信号分子,硫化氢在生物体内具有许多重要的生理功能,因此发展灵敏度高、选择性好的硫化氢荧光探针以实现其实时跟踪和检测成为研究的热点。本文利用NBD荧光配体构建了一个基于其铜配合物的硫化氢荧光探针。铜离子的荧光猝灭作用使得该配合物探针的荧光很弱,而Na2S(硫化氢供体)的加入可显著增强其荧光。研究表明其他阴离子对配合物探针的荧光影响很小,共存时也不会干扰探针对硫化氢的增强响应。研究认为S2-对铜离子(Cu2+)的高亲和能力促使配合物脱铜可能是其实现荧光增强识别的机制。该探针在1～20μmol·L-1的范围内对H2S具有线性响应能力,而且检测限可达到0.2μmol·L-1,是目前检测限较低的少数探针之一。     

Nucleic acid-based fluorescent probes and their analytical potential

It is well known that nucleic acids play an essential role in living organisms because they store and transmit genetic information and use that information to direct the synthesis of proteins. However, less is known about the ability of nucleic acids to bind specific ligands and the application of oligonucleotides as molecular probes or biosensors. Oligonucleotide probes are single-stranded nucleic acid fragments that can be tailored to have high specificity and affinity for different targets including nucleic acids, proteins, small molecules, and ions. One can divide oligonucleotide-based probes into two main categories: hybridization probes that are based on the formation of complementary base-pairs, and aptamer probes that exploit selective recognition of nonnucleic acid analytes and may be compared with immunosensors. Design and construction of hybridization and aptamer probes are similar. Typically, oligonucleotide (DNA, RNA) with predefined base sequence and length is modified by covalent attachment of reporter groups (one or more fluorophores in fluorescence-based probes). The fluorescent labels act as transducers that transform biorecognition (hybridization, ligand binding) into a fluorescence signal. Fluorescent labels have several advantages, for example high sensitivity and multiple transduction approaches (fluorescence quenching or enhancement, fluorescence anisotropy, fluorescence lifetime, fluorescence resonance energy transfer (FRET), and excimer-monomer light switching). These multiple signaling options combined with the design flexibility of the recognition element (DNA, RNA, PNA, LNA) and various labeling strategies contribute to development of numerous selective and sensitive bioassays. This review covers fundamentals of the design and engineering of oligonucleotide probes, describes typical construction approaches, and discusses examples of probes used both in hybridization studies and in aptamer-based assays.     

激发态分子内质子转移荧光探针的研究进展

荧光探针凭借其选择性好、灵敏度高、响应时间快、易于操作和检测限低等优点得到了广泛的关注。 激发态分子内质子转移(ESIPT)化合物具有特殊的激发态光物理过程,其显著的光物理性质是有较高的荧光量子产率及大的斯托克斯位移。 对于荧光分子而言,较大的斯托克斯位移可以减少自吸收和由内滤效应产生的干扰,增强分子的耐光性,有利于荧光的发射。 本文对ESIPT荧光探针检测离子(包括金属阳离子和阴离子)、中性小分子和生物大分子的研究进展进行阐述,并对ESIPT荧光分子的存在问题和应用前景进行评述。     

Correlations of structure and rates of energy transfer for through-bond energy-transfer cassettes

Fluorescent DNA-labeling cassettes are designed to have a common absorbing chromophore matched to a single exciting laser wavelength, but up to four different emitters. Experiments reported here have examined the energy-transfer rates and fluorescence polarization characteristics for two different types of cassette, involving three distinct relative orientations of the donor and acceptor transition moments and the axis of the rigid linker. Energy-transfer times range from <200 fs to approximately 20 ps, the fastest transfer times occurring when the transition moments of the donor and acceptor species are aligned parallel to the linker axis. Experimental evidence is presented that supports a through-bond energy-transfer mechanism, in contrast with a commercial DNA-labeling agent, which exhibits much slower transfer times controlled by FRET. These rigid cassettes also exhibit polarized fluorescence from the acceptor species, so that this particular type of DNA-labeling probe has some of the advantages of single-molecule probes such as rhodamine and coumarin dyes.     

Ratiometric Zn2+ sensor and strategy for Hg2+ selective recognition by central metal ion replacement

Strategies of both self-assembly and metal ion replacement were adopted in the development of new metal ion sensors for Zn2+ and Hg2+. Ligand BPBA, phenylene-bridged bis(pyrrol-2-ylmethyleneamine), could self-assemble to form a molecular square in the presence of Zn2+, which showed strong emission in solution. The fluorescent emission of formed BPBA-Zn2+ dropped with the addition of Hg2+. BPBA could be a good Zn2+ sensor candidate and BPBA-Zn2+ could be a good Hg2+ sensor candidate based on the mechanisms of the chelation-enhanced fluorescence effect and the replacement of central metal ion induced chelation-enhanced fluorescence quenching effect, respectively.     

Rational design of novel photoinduced electron transfer type fluorescent probes for sodium cation

We have developed novel fluorescence probes for sodium cation based on photoinduced electron transfer (PeT). In this study, we rationally designed new probes and succeeded in achieving fluorescence enhancement upon sodium ion binding by reducing the HOMO energy level of the chelator group within the probe molecule. Our new probes show low pH dependency, possibly because of their simple structures. Our results confirm the value of rational probe design based on PeT.     

苯乙烯类菁染料pH探针的合成与活细胞成像

合成了一个以苯乙烯类菁染料为母体的含胺类基团的pH荧光探针, 合成方法简单, 产物收率高, 提纯方便. 在乙醇-水体系中的性能测试结果表明, 随着pH值的降低, 其非质子化形态的吸收峰强度逐渐降低, 而质子化形式的长波长吸收峰强度逐渐升高, 长、短波长相差(Δλ)130 nm, 颜色由黄色变成粉红色, 利于可视观察; 探针在氨基呈非质子化形式时没有荧光, 氨基质子化后探针的荧光强度显著增强. 活细胞实验表明, 探针可以穿透细胞膜, 在细胞质内pH值偏低区域显示红色荧光, 可以用来定性探测酸性细胞器.     

Nanoprobes for super-resolution fluorescence imaging at the nanoscale

Compared with other imaging techniques,fluorescence microscopy has become an essential tool to study cell biology due to its high compatibility with living cells.Owing to the resolution limit set by the diffraction of light,fluorescence microscopy could not resolve the nanostructures in the range of<200 nm.Recently,many techniques have been emerged to overcome the diffraction barrier,providing nanometer spatial resolution.In the course of development,the progress in fluorescent probes has helped to promote the development of the high-resolution fluorescence nanoscopy.Here,we describe the contributions of the fluorescent probes to far-field super resolution imaging,focusing on concepts of the existing super-resolution nanoscopy based on the photophysics of fluorescent nanoprobes,like photoswitching,bleaching and blinking.Fluorescent probe technology is crucial in the design and implementation of super-resolution imaging methods.     

Detection of zinc ions by differential circularly polarized fluorescence excitation

A new chiroptical spectroscopic approach, differential circularly polarized fluorescence excitation (CPE), can be used to provide a selective method for detecting the presence of zinc ions. The approach utilizes the same instrumentation as fluorescence-detected circular dichroism and provides strong contrast in metal detection due to response to both chelation-enhanced fluorescence and circular dichroism upon metal ion binding. The observed contrast is therefore better than either of the parent spectroscopic detection methods. CPE also provides a strategy to reduce interference from background such as protein-based tryptophan fluorescence.     

Pathways for fluorescence quenching in 2-aminopurine π-stacked with pyrimidine nucleobases

Fluorescent analogues of nucleobases are very useful as probes to study DNA dynamics, because natural DNA does not fluoresce significantly. In many of these analogues, such as 2-aminopurine (2AP), the fluorescence is quenched when incorporated into DNA through processes that are not well understood. This work uses theoretical studies to examine fluorescence quenching pathways in 2AP-containing dimers. The singlet excited states of π-stacked dimer systems containing 2AP and a pyrimidine base, thymine or cytosine, have been studied using ab initio computational methods. Computed relaxation pathways along the excited-state surfaces reveal novel mechanisms that can lead to fluorescence quenching in the π-stacked dimers. The placement of 2AP on the 5' or 3' terminus of the dimers has different effects on the excitation energies and the relaxation pathways on the S(1) excited state. Conical intersections between the ground and first excited states exist when 2AP is placed at the 3' side, whereas the placement of 2AP at the 5' side leads to the switching of a bright state to a dark state. Both of these processes can lead to fluorescence quenching and may contribute to the fluorescence quenching observed in 2AP when incorporated in DNA.