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.     

基于锰掺杂量子点的噁喹酸荧光共振能量转移检测研究

基于噁喹酸对锰掺杂硫化锌量子点的荧光猝灭作用,建立了一种噁喹酸荧光共振能量转移检测方法.噁喹酸对量子点的荧光猝灭是由于生成了新的复合物而造成的静态猝灭,二者相互作用过程中焓变ΔH ＜ 0,熵变ΔS ＜ 0,分子间作用力为氢键或范德华力.在0～65 μg/L线性范围内,噁喹酸质量浓度与量子点荧光抑制率呈现良好的线性关系(...     

基于1,8-萘酰亚胺与罗丹明B间荧光共振能量转移的高选择性Hg2+比率荧光探针

以罗丹明B与1,8-萘二甲酰亚胺反应合成了1个高选择性Hg²⁺比率荧光探针(RN). 在甲醇/乙腈/4-羟基哌嗪乙磺酸缓冲溶液(pH=7.2, 体积比8:1:1)中, RN对Hg²⁺具有比色和比率荧光双重响应. 加入Hg²⁺后, RN的紫外-可见光谱在约556 nm处产生强吸收, 溶液由浅绿色变为橙色, 其它金属离子对RN的紫外-可见光谱几乎无影响. 无Hg²⁺存在时, RN的荧光光谱在540 nm处出现萘二甲酰亚胺荧光团的特征峰; 加入Hg²⁺后, 540 nm处的发射带逐渐消失, 同时在580 nm附近产生强荧光, 荧光颜色从绿色变为橙色. 这归因于从萘酰亚胺到开环罗丹明B的荧光共振能量转移(FRET), 探针RN对Hg²⁺的比率荧光响应具有高选择性, 不受其它共存金属离子的干扰.     

吲哚啉螺萘并噁嗪在异丙醇中的酸致变色研究

在异丙醇溶剂中,1,3,3-三甲基螺[吲哚啉-2,3＇-[2H]萘并[2,1-b][1,4](口恶)嗪](SP1)和1,3,3-三甲基-9’-甲氧基螺[吲哚啉-2,3＇-[2H]萘并[2,1-b][1,4](口恶)嗪](SP2)与盐酸在室温下可以形成复合物,复合物的最大吸收分别为440nm和463nm.酸性介质中,螺(口恶)嗪的开环体以两性离子形式与酸相互作用形成了近似于以离子键相结合的复合物(PMC·HCI),其吸收光谱与中性溶液中螺(口恶)嗪环体相比显著蓝移,稳定性增加. 测定了开环体酸致变色产物的消色动力学.在20℃时,有色体的寿命分别为180s和200s.     

新型萘酰亚胺-氟硼二吡咯荧光分子的合成、荧光共振能量转移及细胞成像

通过Click反应合成了萘酰亚胺-氟硼二吡咯复合结构荧光分子1-(2-(4-(1,3,5,7-四甲基氟硼二吡咯基)苯氧基)乙基)-4-(4-N-正丁基-1,8-萘酰亚胺)-1,2,3-三唑(NP-BODIPY),化合物结构经核磁共振氢谱、核磁共振碳谱以及高分辨质谱确征.NP-BODIPY存在从萘酰亚胺能量给体到氟硼二吡咯能量受体之间的分子内荧光共振能量转移.制备了负载萘酰亚胺-氟硼二吡咯荧光染料NP-BODIPY的二氧化硅荧光纳米粒子NP-BODIPY/Si O_2,粒径为50 nm,测定了NP-BODIPY的紫外可见吸收及荧光光谱.NP-BODIPY的固体在暗室中紫外灯下呈紫红色荧光;NP-BODIPY的THF溶液呈明亮的绿色荧光,荧光发射在430和510 nm呈双峰结构,荧光量子产率为0.67,紫外吸收位于366和500 nm;NP-BODIPY在含水量为80%H_2O/THF混合溶液中的荧光较强,荧光量子产率为0.39,最大荧光峰位于510 nm.将其与人乳腺癌细胞(MCF-7)共同孵化,荧光染料纳米粒子进入MCF-7细胞内并清晰成像.NP-BODIPY/Si O_2荧光纳米粒子亲水性好,尺寸可控,细胞毒性低,生物相容性优,可广泛应用于生物标记及荧光成像.     

基于上转换荧光共振能量转移的ClO~-纳米探针

以"核-内壳-外壳"三层夹心结构上转换纳米材料(Sandwich Structure Upconversion Nanoparticles,SWUCNPs)为能量供体,异硫氰酸荧光素(FITC)为能量受体,构建了一种基于上转换荧光共振能量转移(UC-FRET)的纳米探针,其荧光猝灭效率高达95%。将该纳米探针用于水溶液中ClO~-的检测,ClO~-对配体的氧化使得能量供受体之间距离增大,上转换荧光恢复程度与ClO~-的浓度呈线性关系,线性范围为0.02~3.4mmol/L,检出限为0.008mmol/L。实验结果表明该纳米探针特异性强、灵敏度高、结构灵活。     

基于纳米银-曙红Y-DNA的荧光共振能量转移探针

以曙红Y-DNA为荧光探针,运用紫外可见光谱法、荧光光谱法和电泳法研究了纳米银与曙红Y-DNA之间的共振能量转移,并应用能量共振转移的原理解释了纳米银及曙红Y与DNA之间的相互作用。结果表明,曙红Y与DNA的作用方式为嵌插作用,纳米银与DNA的作用方式为静电作用,曙红Y和纳米银结合到DNA上以后,导致了DNA结构的改变。     

两种萘酰亚胺类化合物及其聚合物荧光性质的研究

本文以1,8萘酰亚胺为原料,合成了两种萘酰亚胺类型的化合物,系统地研究了它们在不同溶剂中的吸收光谱和荧光光谱.并以这两种化合物单体为基础,通过共聚合成了它们与甲基丙烯酸甲酯和N 乙烯基咔唑的嵌段共聚物.研究了聚合物在溶液和薄膜中的荧光性质.研究结果证明,所得共聚物不但保持了单体的基本荧光特性,其溶解性、成膜性、热稳定性等都得到了大大改善,是一种有应用前景的有机发光半导体材料.此外,本文还利用荧光猝灭的手段研究了萘酰亚胺类化合物与C₆₀之间的相互作用.     

Development of a new fluorescent probe for transition metal cations based upon fluorescence resonance energy transfer

A novel fluorescent probe for metal cations, which has a large Stokes shift, was synthesized from the reaction of N-(3-carboxy-2-naphthyl)-ethylenediamine-N,N′,N′-triacetic acid (CNEDTA) with 4-(N,N-dimethylaminosulfonyl)-7-(2-aminoethylamino)-2,1,3-benzoxadiazole (DBD-ED). The large Stokes shift is due to the FRET phenomenon between a donor (CNEDTA) and an acceptor (DBD-ED) fluorophore. When the fluorescent probe, DBD-ED-CNEDTA, was excited at 240, 340 and 440 nm, an emission maximum was observed only at 560 nm. However, the fluorescence (FL) at 480 nm, based upon the CNEDTA moiety, was not detected with excitation at 340 nm. The FL intensity of DBD-ED-CNEDTA was dependent upon the acidity of the medium and highest at pH 4.1. DBD-ED-CNEDTA reacted with metal cations, i.e., Zn, Cd, Al, Y, and La, in aqueous medium to form chelates. The spectral change of FL excitation and emission was small before and after the addition of the metal ions. However, the FL intensity was dependent upon the concentrations of the metal ions. In the case of Zn²⁺, the molar ratio bound with DBD-ED-CNEDTA was calculated as 1:1. The FL intensities after chelate formation of Zn/DBD-ED-CNEDTA (1:1) were enhanced by 3.8-fold (excitation at 340 nm, emission at 560 nm), 4.2-fold (excitation at 440 nm, emission at 560 nm), and 5.9-fold (excitation at 240 nm, emission at 560 nm), respectively. The FL probe was applied to the determination of Zn in a food supplement.     

Sensitive turn-on fluorescent detection of tartrazine based on fluorescence resonance energy transfer

We introduce a sensitive, rapid, label-free and general fluorescent method for the determination of tartrazine by competitive binding to reduced graphene oxide (rGO) against fluorescein, and the fluorescence recovery upon fluorescein desorption from rGO provides a quantitative readout for tartrazine, giving a detection limit of 0.53 ng mL(-1).     

Sensitive turn-on fluorescent detection of melamine based on fluorescence resonance energy transfer

We here report a novel fluorescent method for the detection of melamine based on the high fluorescence quenching ability of gold nanoparticles. The fluorescence was significantly quenched via fluorescence resonance energy transfer when fluorescein molecules were attached to the surface of gold nanoparticles by electrostatic interaction. Upon addition of melamine, the fluorescence was enhanced due to the competitive adsorption of gold nanoparticles between melamine and fluorescein. Under the optimum conditions, the fluorescence enhancement efficiency [(I-I(0))/I(0)] showed a linear relationship with the concentration of melamine in the range of 1.0 × 10(-7) mol L(-1)~4.0 × 10(-6) mol L(-1), and the detection limit was calculated to be 1.0 × 10(-9) mol L(-1). The proposed method showed several advantages such as high sensitivity, short analysis time, low cost and ease of operation.     

A novel Cr turn-on probe based on naphthalimide and BINOL framework

Naphthalimide and BINOL framework based fluorescent probe NP-B was rationally designed and synthesized. NP-B exhibited ‘turn-on’ fluorescence for Cr³⁺ and high selectivity over other metal ions. 1:1 binding mode between NP-B and Cr³⁺ was proposed and the mode was verified through MALDI-TOF mass spectrum. The detection limit was calculated to be 0.20 μM, which indicated the good sensitivity for Cr³⁺.     

Donor-conformation-dependent energy transfer for dual-color fluorescent probe with high-resolution imaging

Herein, we presented a brand-new concept to construct the Forster resonance energy transfer(FRET) based cassette by integrating a vibration-induced emission(VIE) chromophore as the donor. Different from traditional donors only with a single emission, the VIE donor possessed well-separated dual emission bands by altering the excited state molecular configuration from the bent state to the planar state. By linking an acceptor such as a cyanine dye(Cy5), a novel VIE-FRET cassette(PPCy5) was prepared. The planar emission profile of the VIE donor moiety could fully cover the absorption of Cy5, and thus the complete FRET process enabled the excellent bimodal spectra difference of 142 nm and ultra-large pseudo-Stokes shift of up to 300 nm.Benefiting from the viscosity-dependent characteristic of the VIE donor, PPCy5 could clearly and intuitively reveal the different viscosity regions in vivo by dual-color and high-resolution imaging. The VIE-FRET paradigm provides an optional platform for developing donor-acceptor-based dual-color fluorescent probes with high-resolution imaging ability.     

A ratiometric fluorescent probe based on boron dipyrromethene and rhodamine Förster resonance energy transfer platform for hypochlorous acid and its application in living cells

We have developed a ratiometric fluorescent probe BRT based on boron dipyrromethene (BODIPY) and rhodamine-thiohydrazide Förster resonance energy transfer (FRET) platform for sensing hypochlorous acid (HOCl) with high selectivity and sensitivity. The probe can detect HOCl in 15 s with the detection limit of 38 nM. Upon mixing with HOCl the fluorescence colour of probe BRT changed from green to orange. Moreover, probe BRT was applied to successfully monitor HOCl in living RAW 264.7 cells.     

Cation-mediated energy transfer in G-quadruplexes revealed by an internal fluorescent probe

A single pyridine unit incorporated into G-quadruplex DNA has revealed efficient energy transfer reactions in cation-containing G-quadruplexes. 8-(2-Pyridyl)-2'-deoxyguanosine, "2PyG", is a highly sensitive internal fluorescent probe of G-quadruplex folding and energy transfer. 2PyG was minimally disruptive to G-quadruplex folding and exhibited intense fluorescence, even when it was base-stacked with other guanine residues. Using 2PyG we have quantified energy transfer efficiencies within G-quadruplex structures prepared under conditions of excess Na(+)/K(+) (110 mM) or in 40% polyethylene glycol (PEG) under salt deficient conditions. G-quadruplex structures containing coordinated cations exhibited efficient DNA-to-probe energy transfer reactions (η(t) = 0.11-0.41), while PEG-folded G-quadruplexes exhibited very little energy transfer (η(t) = 0.02-0.07). Experiments conducted using unmodified G-quadruplexes suggest that cation coordination at the O(6) position of guanine residues results in enhanced quantum yields of G-quadruplex nucleobases that, in turn, serve as efficient energy donors to 2PyG. Given the growing interest in G-quadruplex-based devices and materials, these results will provide important design principles toward harnessing the potentially useful photophysical properties of G-quadruplex wires and other G-rich structures.     

A novel design method of ratiometric fluorescent probes based on fluorescence resonance energy transfer switching by spectral overlap integral

A ratiometric measurement, namely, simultaneous recording of the fluorescence intensities at two wavelengths and calculation of their ratio, allows greater precision than measurements at a single wavelength, and is suitable for cellular imaging studies. Here we describe a novel method of designing probes for ratiometric measurement of hydrolytic enzyme activity based on switching of fluorescence resonance energy transfer (FRET). This method employs fluorescent probes with a 3'-O,6'-O-protected fluorescein acceptor linked to a coumarin donor through a linker moiety. As there is no spectral overlap integral between the coumarin emission and fluorescein absorption, the fluorescein moiety cannot accept the excitation energy of the donor moiety and the donor fluorescence can be observed. After cleavage of the protective groups by hydrolytic enzymes, the fluorescein moiety shows a strong absorption in the coumarin emission region, and then acceptor fluorescence due to FRET is observed. Based on this mechanism, we have developed novel ratiometric fluorescent probes (1-3) for protein tyrosine phosphatase (PTP) activity. They exhibit a large shift in their emission wavelength after reaction with PTPs. The fluorescence quenching problem that usually occurs with FRET probes is overcome by using the coumarin-cyclohexane-fluorescein FRET cassette moiety, in which close contact of the two dyes is hindered. After study of their chemical and kinetic properties, we have concluded that compounds 1 and 2 bearing a rigid cyclohexane linker are practically useful for the ratiometric measurement of PTPs activity. The design concept described in this paper, using FRET switching by spectral overlap integral and a rigid link that prevents close contact of the two dyes, should also be applicable to other hydrolytic enzymes by introducing other appropriate enzyme-cleavable groups into the fluorescein acceptor.     

Simple chemiluminescence aptasensors based on resonance energy transfer

In the present work, two aptamer-based probes and related sensor systems were developed with chemiluminescence signaling. The detection was based on "turning-on" chemiluminescence with switching "off" of the resonance energy transfer after the aptamer's recognition of the target molecule. In this design, a DNA/aptamer duplex linked a chemiluminescence group and a gold nanoparticle together. Only low-intensity chemiluminescence was obtained due to the highly efficient resonance energy transfer. After introducting the target molecule, structure-switching took place with turning off the energy transfer; thus, a restoration and turning on of the chemiluminescence was obtained. The two designs differed in the chemiluminescence groups, since one was a covalently linked luminol molecule, while the other was a conjugated horseradish peroxidase for the catalysis of further chemiluminescence reactions. These schemes provided simple and effective sensing toward a model analyte, adenosine.