一例喹喔啉酰腙荧光探针对锌离子的选择性高灵敏识别及细胞成像应用

通过缩合反应制备了一例席夫碱荧光探针2-喹喔啉甲醛缩2-吡啶酰肼(1),使用核磁共振氢谱和碳谱及质谱等手段表征了探针的结构。荧光光谱分析表明,探针1自身无荧光,而Zn²⁺能够导致其在500 nm处出现强发射峰。该荧光增强能够在常见阳离子中选择性检测 Zn²⁺,检测限低至 0.16 μmol·L^-1。通过核磁、质谱和紫外等手段推测了探针 1与 Zn²⁺可能的配位模式。通过单晶X射线衍射解析了1-Zn²⁺配合物的晶体结构,进一步确认了探针的配位行为。1-Zn²⁺晶体中探针分别采取ONN和NN配位模式螯合2个Zn²⁺,并由桥联CH₃O^-和Cl^-连接形成一维链状结构。此外,该探针还可用于活细胞中Zn²⁺的检测。     

一种同时分辨识别Zn2+和F-离子的双功能探针

由8-甲酰基-7-羟基香豆素与碳酰肼经一步缩合反应可制得探针1。研究发现,探针1对Zn²⁺和F^-离子均呈现荧光增强和比率比色的高灵敏和高选择性响应,检出限低至10^-8 mol·L^-1。通过光谱、ITC、¹H NMR滴定及质谱分析,详细地研究了探针与离子形成的配合物性质。在不同的介质中,探针不仅同时表现出对金属阳离子Zn²⁺和对阴离子F^-的识别,而且吸收和发射波长均有显著的差异：1-Zn²⁺配合物的最大吸收波长为360 nm,而1-F^-配合物为400 nm;1-Zn²⁺配合物的荧光激发和发射波长分别为360和454 nm,而1-F^-配合物分别为400和475 nm。此外,探针1还能应用于活体PC3细胞中Zn²⁺的荧光成像。     

一种同时分辨识别Zn2+和F-离子的双功能探针

由8-甲酰基-7-羟基香豆素与碳酰肼经一步缩合反应可制得探针1。研究发现,探针1对Zn²⁺和F^-离子均呈现荧光增强和比率比色的高灵敏和高选择性响应,检出限低至10^-8 mol·L^-1。通过光谱、ITC、¹H NMR滴定及质谱分析,详细地研究了探针与离子形成的配合物性质。在不同的介质中,探针不仅同时表现出对金属阳离子Zn²⁺和对阴离子F^-的识别,而且吸收和发射波长均有显著的差异：1-Zn²⁺配合物的最大吸收波长为360 nm,而1-F^-配合物为400 nm;1-Zn²⁺配合物的荧光激发和发射波长分别为360和454 nm,而1-F^-配合物分别为400和475 nm。此外,探针1还能应用于活体PC3细胞中Zn²⁺的荧光成像。     

核酸适体修饰纳米金共振散射光谱探针快速检测痕量Pb2＋

以柠檬酸三钠做稳定剂, 用硼氢化钠还原氯金酸制备了粒径为5 nm的纳米金. 用铅离子核酸适体aptamer保护纳米金获得了检测铅离子的适体纳米金(aptamer-NG)共振散射光谱探针. 在pH 7.0的Na₂HPO₄-NaH₂PO₄缓冲溶液中及30 mmol•L^－1 NaCl存在下, aptamer-NG稳定而不聚集. Pb^2＋可与该探针中的aptamer形成非常稳定的G-四分体结构, 并释放出纳米金. 在NaCl作用下纳米金聚集形成较大的微粒, 导致552 nm处共振散射峰强度增大. Pb^2＋浓度在0.07～42 nmol•L^－1范围内与552 nm处共振散射强度增大值ΔI成线性关系, 其回归方程为ΔI＝12.0c＋9.2, 线性相关系数为0.9965, 方法检出限为0.03 nmol•L^－1 Pb^2＋. 该方法用于水样中铅离子检测, 结果与石墨炉原子吸收光谱法结果一致.     

一种用于活细胞中检测Zn2+的萘酚席夫碱类荧光探针

设计合成了1种基于C=N异构化和螯合荧光增强机理（CHEF）的Zn²⁺荧光探针BMO和NBMO,其结构经¹H NMR,¹³C NMR,¹H-¹H COSY,HSQC,IR和HRMS进行了表征。光谱分析实验结果显示,探针对Zn²⁺均具有较好的选择性和灵敏度,检出限分别为30和21 nmol·L^-1。在0~20 μmol·L^-1浓度的范围内,BMO和NBMO的荧光强度与Zn²⁺浓度可呈良好的线性关系。NBMO-Zn²⁺配合物单晶结构和Job曲线证实该探针与Zn²⁺以1：1配位。NBMO被成功应用于活细胞中Zn²⁺的检测。     

基于席夫碱的四种Zn2+荧光探针的合成及其性能

以乙二胺与水杨醛及其衍生物为原料,构建了4种席夫碱Zn²⁺荧光探针,其结构均由¹H NMR、¹³C NMR和IR进行了表征。光谱分析实验结果表明,相比于其他探针,探针L2对Zn²⁺具有更好的选择性和灵敏度,检出限为92.15 nmol·L^-1。在0~30μmol·L^-1的浓度范围内,探针L2的荧光强度与Zn²⁺浓度可呈良好的线性关系,在紫外灯下可用肉眼观察到明显颜色变化。通过Job曲线、核磁滴定实验、密度泛函理论计算和L2-Zn²⁺配合物单晶结构对识别机理进行了研究,结果表明探针L2与Zn²⁺以物质的量之比1∶1配位。此外,探针L2还可用于检测实际水样中的Zn²⁺。     

1,8-萘酰亚胺为发色团的Zn2+荧光探针的合成及性能研究

合成了以1,8-萘酰亚胺为发色团,以联吡啶为离子受体的Zn²⁺荧光探针,并进行了表征及离子识别性能的研究。研究表明该化合物对Zn²⁺具有良好的识别性能,同时相对于Ca²⁺, Cd²⁺, Co²⁺, Cu²⁺, Hg²⁺, Fe³⁺, Mn²⁺, Ni²⁺, Pb²⁺等金属离子具有良好的选择性。     

M(EDTA)2－ (M＝Co, Ni, Cu, Zn, Cd)电子结构和性质的密度泛函理论研究

在B3LYP/LanL2DZ水平上, 计算研究了Co^2＋, Ni^2＋, Cu^2＋, Zn^2＋, Cd^2＋与乙二胺四乙酸(EDTA)六配位模式下配合物的结构和性质. 除Cu(EDTA)^2－的M—O(5)受Jahn-Teller效应影响明显拉长外, 配位键长M—N(1)和M—O(5)按 Cu^2＋＜Ni^2＋＜Co^2＋＜Zn^2＋＜Cd^2＋的顺序依次增长, 配位键长M—O(3)按Cu^2＋＜Zn^2＋＜Ni^2＋＜Co^2＋＜Cd^2＋的次序依次增长. 自然键轨道(NBO)分析表明, 氮、氧的非键电子与金属空轨道的相互作用是配体与金属离子配位的主要作用方式. 通过对N(1)—C(7), N(1)—C(9), N(1)—C(15)键长和NAO键级的分析, 在分子水平上阐明了EDTA在与金属离子配位前后发生首步降解, 其产物存在差异的实验事实. 依据热力学原理并兼顾自洽反应场(SCRF)的IEFPCM模型, 我们设计了金属离子与EDTA在水溶液中的反应途径和热力学循环. 结果表明, 金属离子与EDTA的结合能(即配位稳定性)依次为: Cd^2＋＜Zn^2＋＜Co^2＋＜Ni^2＋＜Cu^2＋, 金属离子的水合吉布斯自由能计算值与实验值大致吻合, 而且上述目标金属配合物的络合吉布斯自由能的递变规律与实验一致. 基于气相优化结构进行了振动频率计算, 并对部分重要的振动峰作了归属指认. 结果表明, 随着配位稳定性的减弱, M(EDTA)^2－具有红外活性的金属敏感性振动峰ν(M—N)和ν(M—O)的峰位依次红移.     

基于苯并噻唑Zn2+荧光探针及其细胞造影应用

设计合成基于苯并噻唑Zn²⁺荧光增强型探针BHP,在HEPES缓冲液中测其对Zn²⁺识别性能。实验结果表明,BHP对Zn²⁺有较高的选择性,对其他金属离子如Cd²⁺,Fe²⁺,Ni²⁺,Pb²⁺,Hg²⁺,Al³⁺,Mn²⁺,Ag⁺,Cu²⁺,Co²⁺,Na⁺,K⁺,Mg²⁺和Ca²⁺无明显荧光增强响应。BHP与Zn²⁺按1：1计量比配位,在生理条件下荧光强度不受pH值影响。在HeLa细胞中对Zn²⁺的造影表明BHP可用于生物体Zn²⁺检测。     

含磷酰杂菲苯甲酸对苯二酯的聚集诱导发光增强性能及其在检测过渡金属离子中的应用

有机化合物因成膜以后荧光淬灭而使其应用受到很大限制, 所以研究、开发能在聚集状态下呈现优异发光性能的新材料就尤为重要. 由于分子间π-π和极性共同相互作用, 使得磷酰杂菲环的转动受到限制, 从而使苯甲酸-2-[6-氧化-6-氢-二苯基(c,e)＜1,2＞氧杂磷酰基]-1,4-二羟基苯二酯(OP)在达到一定规整聚集程度时, 荧光强度成倍增加, 具有了聚集诱导发光增强(AIEE)性质. 实验结果表明: 浓度低于1×10^－6 mol•L^－1 的OP会失去AIEE性质; 浓度为1×10^－4 mol•L^－1的Hg^2＋, Fe^2＋和 Fe^3＋会分别淬灭浓度为1×10^－5 mol•L^－1 OP荧光强度的26%, 34%, 74%, 而Pb^2＋, Zn^2＋, Cd^2＋, Co^2＋, Mn^2＋, Cu^2＋, Ni^2＋, Ag^＋等离子的淬灭效率却很低, 这一性质表明该化合物可以用作过渡金属离子的特异性检测材料.     

Ratiometric and turn-on monitoring for heavy and transition metal ions in aqueous solution with a fluorescent peptide sensor

A novel fluorescent peptide sensor containing tryptophan (donor) and dansyl fluorophore (acceptor) was synthesized for monitoring heavy and transition metal (HTM) ions on the basis of metal ion binding motif (Cys-X-X-X-Cys). The peptide probe successfully exhibited a turn on and ratiometric response for several heavy metal ions such as Hg²⁺, Cd²⁺, Pb²⁺, Zn²⁺, and Ag⁺ in aqueous solution. The enhancements of emission intensity were achieved in the presence of the HTM ions by fluorescent resonance energy transfer (FRET) and chelation enhanced fluorescence (CHEF) effects. The detection limits of the sensor for Cd²⁺, Pb²⁺, Zn²⁺, and Ag⁺ were lower than the EPA's drinking water maximum contaminant levels (MCL). We described the fluorescent enhancement, binding affinity, and detection limit of the peptide probe for HTM ions.     

An NBD-based colorimetric and fluorescent chemosensor for Zn and its use for detection of intracellular zinc ions

A new 7-nitrobenz-2-oxa-1,3-diazole (NBD) based colorimetric and fluorescence chemosensor for Zn²⁺, an ion involved in many biological processes, was designed and synthesized. The NBD-probe 1 displays a red-to-yellow color change and an enhancement of fluorescent intensity in the presence of an aqueous solution of Zn²⁺ ions (pH 7.2). Internal charge transfer (ICT) and photoinduced electron transfer (PET) mechanisms are responsible for these changes. The practical use of this probe was demonstrated by its application to the biologically relevant detection of Zn²⁺ ions in pancreatic β-cells.     

High-Affinity Ratiometric Fluorescence Probe Based on 6-Amino-2,2′-Bipyridine Scaffold for Endogenous Zn2+ and Its Application to Living Cells

Zinc is an essential trace element involved in many biological activities; however, its functions are not fully understood. To elucidate the role of endogenous labile Zn²⁺, we developed a novel ratiometric fluorescence probe, 5-(4-methoxyphenyl)-4-(methylsulfanyl)-[2,2′-bipyridin]-6-amine (6 (rBpyZ)) based on the 6-amino-2,2′-bipyridine scaffold, which acts as both the chelating agent for Zn²⁺ and the fluorescent moiety. The methoxy group acted as an electron donor, enabling the intramolecular charge transfer state of 6 (rBpyZ), and a ratiometric fluorescence response consisting of a decrease at the emission wavelength of 438 nm and a corresponding increase at the emission wavelength of 465 nm was observed. The ratiometric probe 6 (rBpyZ) exhibited a nanomolar-level dissociation constant (K_d = 0.77 nM), a large Stokes shift (139 nm), and an excellent detection limit (0.10 nM) under physiological conditions. Moreover, fluorescence imaging using A549 human lung adenocarcinoma cells revealed that 6 (rBpyZ) had good cell membrane permeability and could clearly visualize endogenous labile Zn²⁺. These results suggest that the ratiometric fluorescence probe 6 (rBpyZ) has considerable potential as a valuable tool for understanding the role of Zn²⁺ in living systems.     

Synthesis and photophysical properties of a fluorescent TREN-type ligand incorporating the coumarin chromophore and its zinc complex

A new, UV-excited fluorescent Zn²⁺ indicator was synthesized and the spectral profile of its free and Zn²⁺ bound forms were studied. The fluorescent properties of this probe are due to the 7-amino-4-methylcoumarin fluorophore, which is conjugated with the tris(2-aminoethyl)amine (TREN) that functions as the zinc-chelating moiety. The compound exhibits a Zn²⁺ dissociation constant of 18.0 μM. The fluorescence spectra of the probe showed a clear shift in excitation wavelength maxima upon Zn²⁺ binding, indicating its potential use as ratiometric Zn²⁺ indicator.     

A FRET fluorescent chemosensor SPAQ for Zn based on a dyad bearing spiropyran and 8-aminoquinoline unit

A novel FRET fluorescent sensor SPAQ containing 8-aminoquinoline (donor) and spiropyran derivative (acceptor) was designed and synthesized for detecting Zn²⁺. The probe successfully exhibited a fluorescence turn on and ratiometric response for Zn²⁺ in ethanol solution with high selectivity. Upon excitation at 370 nm, the modulation of the emission intensity of SPAQ at 645 and 470 nm was achieved in the presence of Zn²⁺ by fluorescent resonance energy transfer (FRET) and chelation-enhanced fluorescence (CHEF) effects.     

FRET based selective and ratiometric ‘naked-eye’ detection of CN in aqueous solution on fluorescein–Zn–naphthalene ensemble platform

We have developed a FRET-based ratiometric fluorescent probe for the detection of CN⁻ using a fluorescein–Zn–naphthalene ensemble (NFH·Zn²⁺). The sensing mechanism was ascribed by displacement approach. The chemosensor exhibits high selectivity and sensibility for CN⁻. The speculation was supported by fluorescence emission spectra, UV–vis spectrum, ¹H NMR titration experiments, and mass spectra. The interconversion of probe NFH and NFH·Zn²⁺ via the complexation/decomplexation by the modulation of Zn²⁺/CN⁻ mimics INHIBIT gate. In addition, it also shows an excellent performance in ‘dip stick’ method.     

A dual-response fluorescent probe for Zn and Al detection in aqueous media: pH-dependent selectivity and practical application

A Schiff base-type fluorescent probe (1) consist of 2-hydroxynaphthaldehyde and glutamide moieties has been designed and synthesized for detection Zn²⁺ and Al³⁺. The probe shows pH dependent dual-selectivity for Zn²⁺ and Al³⁺ in Tris-HCl buffer, viz. that can selectively recognized Zn²⁺ at pH 7.4 and Al³⁺ at pH 6.0, respectively. From Job's plots and MS data, the stoichiometric ratios of the probe with Zn²⁺ and Al³⁺ appeared to be 1:1 and 2:1, respectively. The probe can detect as low as 5.5 × 10⁻⁸ M⁻¹ Zn²⁺ and 1.27 × 10⁻⁷ M⁻¹ Al³⁺, whereas respective association constants are 4.27 × 10⁴ M⁻¹ and 3.50 × 10⁹ M⁻¹. Furthermore, it is also confirmed that the probe has good cell-permeability and could thus be used to selectively sense intracellular Zn²⁺ and Al³⁺ by bioimaging in different pH environment. Finally the probe has been used successfully for determination of the analytes in real drug samples.     

一种近红外发射荧光探针的合成及其荧光增强识别Hg2+

汞离子(Hg~(2+))由于高毒性以及容易对环境和人体造成损害,其检测越来越受到人们的重视。本文基于4-(二乙氨基)水杨醛设计合成了一种近红外发射荧光探针L,该探针可在MeCN/HEPES(体积比2/8,pH=7.4)缓冲溶液中高选择性地荧光增强识别Hg~(2+),其具有合成简便、抗干扰能力强、适用pH范围宽等特点。进一步研究表明,探针L可用于真实水样中Hg~(2+)的检测。