一种新型二氰基乙烯修饰的二呋喃环戊烯光开关:荧光性质、传感性能和生物应用（英文）

近年来,借助于高度优化的小分子荧光染料,荧光蛋白和先进的标记技术,荧光标记技术得到了极大的发展.二芳基乙烯光开关荧光染料的研究,主要通过在二芳基乙烯中引入荧光核和对芳基的结构修饰.与噻吩相比,呋喃具有更好的刚性、溶解性和可生物降解能力以及更强的荧光.因此,二呋喃乙烯可以作为荧光标记技术的小分子荧光染料.设计并制备了一种基于二氰基乙烯的二呋喃乙烯新型荧光光开关.该化合物在溶液中呈现典型的可逆光致变色性能,且以其出色的选择性、灵敏度和高对比度来实现氰根离子的荧光检测.此外,通过核磁滴定实验,解释了其对氰根离子的响应机理.由于采用呋喃替换噻吩使得该化合物拥有更强的荧光,成功应用于生物体内的荧光染料和氰根离子探针.     

甲川链修饰菁染料的合成研究进展

在小分子荧光探针中,菁染料由于其良好的光学特性,在成像及生物传感等领域具有广泛应用.甲川链的功能化可以显著提高染料的稳定性并改变其光物理性能和生物选择性,已成为近年来菁染料结构修饰的热点.总结了甲川链修饰菁染料的合成方法,根据甲川链取代基的不同来源,按照甲川链不同长度对甲川链修饰菁染料的研究进展分别进行综述.     

分子印迹荧光传感器研究进展

分子印迹技术是结合高分子化学、分析化学、材料科学等发展起来的一门边缘学科,是模拟受体-抗体相互作用的一种新技术。分子印迹荧光传感器结合了分子印迹聚合物的预定识别性和高选择性以及荧光检测的高灵敏性,成为传感领域的研究热点。本文主要介绍了分子印迹荧光传感器的研究进展,重点概述了分子印迹荧光传感器的制备原理、检测方式及其在有机小分子和离子检测中的应用,并对其发展前景进行了展望。     

荧光碳点在分析传感中的应用进展

荧光碳点（CDs）是2004年发现的一种新型碳基纳米材料,呈球形、粒径在2～10 nm左右,具有优异的荧光性能、易于功能化修饰、抗光漂白性强、环境危害低、生物相容性好以及合成原料来源丰富等特点,被认为是有机荧光染料和半导体量子点的最佳替代品,在光电学、光催化、化学传感和生物成像等领域有着广阔的应用前景。本文主要介绍了CDs作为化学传感器的荧光检测机制,重点总结了近年来CDs在离子、有机小分子以及生物大分子检测等方面的应用,以期为荧光纳米探针的设计与应用提供理论和研究依据。     

荧光传感器阵列

传感器阵列是基于对动物嗅觉系统的认识发展起来的一种有力的分子识别手段,其由一系列传感单元组成,通过各传感单元对样品响应后产生的特征图谱实现对特定物质的识别检测,尤其对混合样品的鉴定具有突出优势。其中,荧光传感器阵列由于具有灵敏度高、无需参照体系、输出信号丰富、能够成像等优点,已成为近年来传感器阵列发展的重点。本综述根据荧光传感单元形式的不同,分别介绍了溶液型、颗粒型、薄膜型荧光传感器阵列的发展情况,并重点阐述了荧光传感器阵列的设计方法、传感机理及其在对金属离子、有机化合物和生物分子识别中的应用。     

用于铁离子检测的荧光传感材料研究进展

准确、定量检测Fe~(3+)对环境保护和人类健康具有重要意义。目前,荧光传感材料广泛应用于分子传感、气体传感、环境监测等诸多领域。为了实现环境监测领域Fe~(3+)的快速响应、高灵敏和高选择性检测,研究者大力开发了各种新型荧光传感材料,本文重点介绍了金属有机骨架(MOFs)、荧光量子点(QDs)、金属纳米簇、荧光小分子和荧光聚合物等各种新型荧光材料在Fe~(3+)检测中的应用;分析了目前荧光传感材料研究中存在的问题和局限性并对其发展方向进行了展望。     

多元线性模型计算基于荧光猝灭原理的膜传感器对分析物的响应参数

根据基于荧光猝灭原理的化学传感膜的结构特征和发光机理,推导并提出量化作用于膜传感器的多种荧光猝灭因素的多元线性模型.结合三杯法,该模型可简便地求出反映不同荧光猝灭机理的特征参数.通过建立的数学模型,测定并计算了芘丁酸膜传感器对应于呋喃妥因等23种药物多种荧光猝灭因素的响应数据和响应参数.结果表明,传感膜对分析物的响应特征往往能得到主要猝灭因素响应模型的近似反映,这为基于荧光猝灭原理的化学传感器定量分析模型的建立提供了可借鉴的思路和方法.     

荧光传感方法检测爆炸物的研究进展

爆炸物检测是当前国际安全中迫切关注的问题之一。在过去的几十年中,大量的荧光传感材料用于荧光传感检测气态、液态和固态爆炸物见诸于报道。近年来,为了实现爆炸物的快速响应、高灵敏和高选择性的检测,研究工作者大力开发了各种新型荧光材料。这篇综述总结了近年来用于爆炸物检测的先进荧光材料,详尽、系统、重点地介绍了共轭聚合物、荧光小分子、超分子体系、具有聚集诱导发光效应的活性材料及静电纺丝纳米材料等各种荧光材料在爆炸物检测中的应用,展望了荧光传感方法在爆炸物检测领域的应用前景。     

基于抑制扭转的分子内电荷转移(TICT)提升有机小分子荧光染料亮度及光稳定性※

有机小分子荧光染料研究已有170余年历史, 其结构和性能随着合成方法和应用需求的发展而不断革新, 已被广泛应用于荧光标记、探针和生物成像中. 近年来发展起来的超分辨荧光成像技术对有机小分子荧光染料的亮度、稳定性和开关性能等均提出了更高的要求, 这为染料发展带来了新的机遇. 当前, 化学工作者也将更多精力聚焦在染料结构改造提升有机小分子荧光染料的亮度与光稳定性. 激发态扭转的分子内电荷转移(TICT)是有机小分子荧光染料中主要的非辐射衰减途径之一. 因而, 抑制TICT能够很好地提升染料的亮度和光稳定性, 并成为目前针对超分辨成像技术发展高亮度和光稳定性的有机小分子荧光染料的主要方法. 本综述首先简要回顾了TICT的机制和发展过程, 而后重点介绍近些年通过抑制TICT策略来提升不同结构有机小分子荧光染料光谱性能方面的进展.     

分子印迹荧光传感构建及应用

构建一个高灵敏、高选择性检测痕量分析物的传感器广受科研工作者关注。分子印迹技术由于具有高选择性识别、高容量吸附、快速结合、热稳定性以及低成本等优点,已广泛应用于传感构建领域。以分子印迹聚合物为识别单元,结合荧光传感技术所构建的分子印迹荧光传感器在环境污染物痕量检测方面成为研究重点。本文主要介绍分子印迹聚合物的制备方法,总结分子印迹荧光传感器的构建机理和分子印迹荧光传感器在金属离子、有机小分子以及生物大分子检测方面的应用。重点探讨分子印迹传感器在不同数量的荧光团下检测一种或多种目标分析物的方法,包括单一荧光团检测单一目标物、比率荧光检测单一目标物以及分子印迹荧光传感的多元检测。基于以上分析和总结,提出分子印迹荧光传感器的当前挑战和发展前景。     

Subunit exchange of MjHsp16.5 studied by single-molecule imaging and fluorescence resonance energy transfer

MjHsp16.5 was separately labeled by fluorescent dye Cy3 and Cy5.5. The dissociation event of a single 24-mer MjHsp16.5 molecule was captured by single-molecule imaging (SMI). Temperature-regulated subunit exchange was revealed by the real-time fluorescence resonance energy transfer (FRET). The combination of single-molecular statistics and kinetic parameters from FRET experiments leads to the conclusion that below 75 degrees C the rate-determining step of the subunit exchange was the dissociation of the dye-labeled 24-mer in which the dimer was intact, whereas above 75 degrees C, smaller units emerged in the exchange and the rate-determining step had the character of a bimolecular reaction.     

Preparation of luminescent Cy5 doped core-shell SFNPs and its application as a near-infrared fluorescent marker

Cy5 dye is widely used as a biomarker in the research fields of life science because of its excitation at wavelengths above 600 nm where autofluorescence of bio-matter is much reduced. However, Cy5 dye could not be encapsulate into silica directly to form stable nanoparticles by using of the traditional methods. In this paper, an improved method had been developed to prepare Cy5 dye doped core-shell silica fluorescent nanoparticles (SFNPs), employing biomolecules conjugated Cy5 as the core material and silica coating produced from the hydrolysis TEOS (tetraethyl orthosilicate) in the water-in-oil microemulsion. To obtain stable Cy5 dye doped SFNPs with core-shell structure, five kinds of biomolecules with different iso-electric point (pI) have been selected to conjugate Cy5 for preparation of core-shell SFNPs. Results demonstrated that very bright and photostable Cy5 doped core-shell SFNPs could be both prepared by use of positive polysine conjugated Cy5 or IgG conjugated Cy5 as the core material, respectively. IgG conjugated Cy5 doped core-shell SFNPs was selected as a demonstration to be characterized and applied as a near-infrared fluorescent marker in cell recognition. The results showed that Cy5 doped core-shell SFNPs prepared by conjugating with a positive biomolecules IgG as the core material were luminescent and stable. About 110 Cy5 dye molecules could be doped in one nanoparticle with size of 42 ± 5 nm. The breast cancer cells had been selectively recognized by use of the near-infrared fluorescent marker based on the Cy5-IgG doped core-shell SFNPs. And the results demonstrated that this Cy5 doped core-shell SFNPs fluorescence marker was superior to the pure Cy5 dye marker for cell recognition in photostability and detection sensitivity.     

Fluorescence properties and photophysics of the sulfoindocyanine Cy3 linked covalently to DNA

The sulfoindocyanine Cy3 is one of the most commonly used fluorescent dyes in the investigation of the structure and dynamics of nucleic acids by means of fluorescence methods. In this work, we report the fluorescence and photophysical properties of Cy3 attached covalently to single-stranded and duplex DNA. Steady-state and time-resolved fluorescence techniques were used to determine fluorescence quantum yields, emission lifetimes, and fluorescence anisotropy decays. The existence of a transient photoisomer was investigated by means of transient absorption techniques. The fluorescence quantum yield of Cy3 is highest when attached to the 5' terminus of single-stranded DNA (Cy3-5' ssDNA), and decreases by a factor of 2.4 when the complementary strand is annealed to form duplex DNA (Cy3-5' dsDNA). Substantial differences were also observed between the 5'-modified strands and strands modified through an internal amino-modified deoxy uridine. The fluorescence decay of Cy3 became multiexponential upon conjugation to DNA. The longest lifetime was observed for Cy3-5' ssDNA, where about 50% of the decay is dominated by a 2.0-ns lifetime. This value is more than 10 times larger than the fluorescence lifetime of the free dye in solution. These observations are interpreted in terms of a model where the molecule undergoes a trans-cis isomerization reaction from the first excited state. We observed that the activation energy for photoisomerization depends strongly on the microenvironment in which the dye is located. The unusually high activation energy measured for Cy3-5' ssDNA is an indication of dye-ssDNA interactions. In fact, the time-resolved fluorescence anisotropy decay of this sample is dominated by a 2.5-ns rotational correlation time, which evidences the lack of rotational freedom of the dye around the linker that separates it from the terminal 5' phosphate. The remarkable variations in the photophysical properties of Cy3-DNA constructs demonstrate that caution should be used when Cy3 is used in studies employing DNA conjugates.     

Acoustic wave detection of chemical species electrokinetically transported within a capillary tube

For the first time, we report the acoustic wave detection of chemical species being transported in a capillary tube to a region where acoustic coupling occurs. The measured parameter was a change in phase, which was originally only attributed to a change in solution density as the analyte passed by the detection region. Accordingly, we report the detection of change in phase as various chemical species (e.g. Cy5 dye, Cy5-derivatized glycine and underivatized glycine) were introduced into and migrated along a capillary tube through electrokinetic processes. To improve detection sensitivity, we modified various experimental parameters, such as run buffer concentration, capillary wall thickness and transducer frequency. Although acoustic wave detection was feasible, the peak width and detection limit were inadequate as compared to conventional detection methods for HPLC or CE. Nevertheless, the effects of various physical and chemical relaxation processes on acoustic wave absorption were discussed, and this has shed some light on explaining some observations, which cannot be explained by density differences alone. Accordingly, the acoustic wave method is suggested to investigate these processes, as studied in ultrasonic relaxation spectroscopy, in a flow system.     

Efficient Cholera Toxin B Subunit‐Based Nanoparticles with MRI Capability for Drug Delivery to the Brain Following Intranasal Administration

Alzheimer's disease (AD) is an incurable neurodegenerative brain disorder that exhibits clear pathologic changes in the hippocampus. Traditional drug delivery systems are ineffective due to the existence of the blood–brain barrier (BBB). In this study, an efficient, stable, and easily constructed nanosystem (CB‐Gd‐Cy5.5) based on the cholera toxin B subunit (CB) is designed to improve the efficiency of drug delivery to the brain, especially the hippocampus. Through intranasal administration, CB‐Gd‐Cy5.5 is easily delivered to the brain without intervention by the BBB. The CB in CB‐Gd‐Cy5.5 is used for specifically combining with the monosialoganglioside GM1, which is widely found in the hippocampus. This nanosystem exhibits impressive performance in accumulating in the hippocampus. In addition, the good magnetic resonance imaging (MRI) capability of CB‐Gd‐Cy5.5 can satisfy the monitoring of AD in the different stages.     

Fluorescent signal amplification of carbocyanine dyes using engineered viral nanoparticles

We report enhancement in the fluorescent signal of the carbocyanine dye Cy5 by using an engineered virus as a scaffold to attach >40 Cy5 reporter molecules at fixed locations on the viral capsid. Although cyanine dye loading is often accompanied by fluorescence quenching, our results demonstrate that organized spatial distribution of Cy5 reporter molecules on the capsid obviates this commonly encountered problem. In addition, we observe energy transfer from the virus to adducted dye molecules, resulting in a highly fluorescent viral nanoparticle. We have used this enhanced fluorescence for the detection of DNA-DNA hybridization. When compared with the most often used detection methods in a microarray-based genotyping assay for Vibrio cholerae O139, these viral nanoparticles markedly increased assay sensitivity, thus demonstrating their applicability for existing DNA microarray protocols.     

基于双色荧光传感器的癌细胞成像及microRNA定量检测

癌细胞中microRNA(miRNA)的灵敏成像对于疾病的诊断治疗具有重要意义, 其中miRNA-21通常在多种癌细胞中异常表达. 本文将DNA功能化的金纳米颗粒与发射波长分离的荧光染料FAM和Cy5.5修饰的DNA通过含有光控基团PC-linker的DNA4作为桥梁进行自组装, 构建了纳米传感器GDC. 将302 nm紫外光作为启动开关, 用其照射该体系时, Cy5.5修饰的DNA3被释放, 其荧光强度可作为内参比信号, 用于标定进入细胞的组装体含量; 细胞中miRNA-21作为催化分子, 与外加燃料Fuel DNA共同作用下可实现催化放大, FAM修饰的DNA2被释放且被猝灭的荧光信号得以恢复, 并作为检测信号. 通过2种荧光信号强度(FL)的检测及FL_FAM/FL_Cy5.5比值的计算, 达到定量分析细胞中miRNA含量的目的. 该体系可扣除因细胞内组装体含量不同造成的背景信号误差, 不仅能显著提高检测准确度, 还因存在催化循环而大大降低了检出限, 比传统方法至少降低了3个数量级. 该传感器的检出限为23.1 pmol/L, 通过定量计算得出HeLa细胞中miRNA的含量为0.0236 nmol/L.     

Synthesis of new azaphthalocyanine dark quencher and evaluation of its quenching efficiency with different fluorophores

New unsymmetrical zinc azaphthalocyanine (AzaPc) was synthesized using statistical condensation of two precursors. Postsynthetic modifications led to incorporation of azide group that efficiently underwent Cu(I)-catalyzed azide/alkyne 1,3-dipolar cycloaddition with terminal alkyne on a solid phase. The modified solid phase was then used for synthesis of oligodeoxyribonucletides labeled with AzaPc. DNA hybridization assays confirmed high quenching efficiency (QE>96%) of zinc AzaPc quencher with six different fluorophores ranging in emission maxima from 517 nm to 701 nm (FAM, HEX, Cy3, Cy3.5, Cy5, and Cy5.5).     

Emerging Design Principle of Near-Infrared Upconversion Sensitizer Based on Mitochondria-Targeted Organic Dye for Enhanced Photodynamic Therapy

Upconversion luminescent (UCL) triggered photodynamic therapy (PDT) affords superior outcome for cancer treatment. However, conventional UCL materials which all work by a multiphoton absorption (MPA) process inevitably need extremely high power density far over the maximum permissible exposure (MPE) to laser. Here, a one-photon absorption molecular upconversion sensitizer Cy5.5-Br based on frequency upconversion luminescent (FUCL) is designed for PDT. The unusual super heavy atom effect (SHAE) in Cy5.5-Br strongly enhances its spin-orbit coupling (0.23 cm⁻¹), triplet quantum yield (11.1 %) and triplet state lifetime (18.8 μs) while the potential hot-band absorption of Cy5.5-Br is well maintained. Importantly, Cy5.5-Br can efficiently target the tumour site and kill cancer cells by destroying mitochondria under a biosafety MPE to 808 nm laser. The photostability and antitumor results are obviously superior to that of a Stokes process. This work provides a design criterion for FUCL dyes to realize effective PDT upon a biosafety optical density, possibly bringing more clinical benefits than conventional MPA materials.     

一种含聚乙二醇非离子亲水基团的新型水溶性荧光染料的合成及细胞成像

通过向吲哚环“N”位上引入一个含聚乙二醇(PEG)醚链的非离子亲水基团,合成了一种新型水溶性不对称五甲川吲哚菁染料。 用核磁(¹H NMR)和高分辨质谱(HRMS)表征染料的结构,测试了染料的光谱性能,标记牛血清白蛋白(BSA),并对固定细胞和活细胞分别染色。 结果表明,该染料在水中的最大紫外吸收波长和荧光发射波长分别为648和668 nm,斯托克斯(stokes)位移为20 nm,荧光量子产率(Ф)为0.13,以碘钨灯为光源光照8 h后,染料光降解率为5.8%。 用染料的NHS活性酯标记牛血清白蛋白,标示率(D/P)为1.16。 对固定细胞染色发现,染料可对细胞整体着色,对细胞核染色最明显,能清晰看到核仁。 对活细胞染色发现,有少量染料跨膜进入细胞内部,对细胞质和细胞核有微弱染色,但在活细胞膜上聚集明显。