水溶性汞离子荧光探针的研究新进展

汞离子(Hg2+)是剧毒的重金属元素之一,对汞离子的选择性识别尤其是汞离子的原位、实时、在线监测对于医学、生物学和环境科学都具有重要意义。本文综述了近5年来水溶性汞离子荧光探针的最新研究进展。按照作用机理来分,汞离子荧光分子探针主要可分为光诱导电荷转移(PET)、激发态分子内质子转移(ESIPT)、激基缔合物(Monomer/Eximer)的形成和消失、分子内电荷转移(ICT)、荧光共振能量转移(FRET)等。本文列举了每类探针代表性的化合物并分析比较了不同机理类型的水溶性汞离子荧光探针体系。     

金属离子及其配合物荧光探针在核酸分析中的应用

核酸是生命现象的物质基础,对于核酸的研究已经成为生命科学的重要内容。荧光法是研究核酸结构、功能和定性、定量的一种重要方法,而稀土离子及其配合物是荧光分析中最常用的探针技术。本文介绍了近十几年来稀土离子及其配合物荧光探针在核酸分析中的应用。     

稀土离子荧光探针在蛋白质分析中的应用

蛋白质是生物体内含量最丰富的生物大分子物质,在人体代谢中扮演重要的角色,它的分析测定在医学和生物学研究中有着重要的意义。荧光方法是研究蛋白质结构,功能和定性定量分析的一种重要方法,而稀土离子及其配合物是荧光分析中最常用的探针技术。本文介绍了近十几年来稀土离子及其配合物荧光探针在蛋白质分析中的应用。     

检测活性氧的荧光探针新进展

活性氧对于人体是十分重要的。然而,过量的活性氧是相当有害的,它们会对人体产生氧化损伤,导致细胞死亡。活性氧现在已经引起了化学、生物、医药等多个领域学者的浓厚兴趣,它们被认为和多种病理条件有密切的联系。由于活性氧寿命短、反应活性高,并且大部分都存在于体内很难被捕获,因此它们的分析测定是一项国际性难题。荧光探针作为活性氧的高灵敏的检测分析物,已经得到越来越广泛和深入的研究。由于每一种活性氧都有它独特的生理学活性,因此设计高选择性的,能够检测具体一种活性氧的荧光探针分子就显得十分重要。本文主要对近三年来检测单线态氧、过氧化氢、超氧阴离子和羟自由基这四种活性氧的荧光探针的研究进展进行综述,关注这类荧光探针的检测机理以及具体应用。     

Metal Nanoclusters–Based Ratiometric Fluorescent Probes from Design to Sensing Applications

Ratiometric fluorescent probes have many advantages including improved sensitivity, high reliability and accuracy, visualization sensing, etc. Herein, the development of metal nanoclusters (NCs)‐based ratiometric fluorescent probes in the recent years is summarized. NCs, an emerging new class of fluorescent nanomaterials, have demonstrated excellent optical properties, good biocompatibility, great aqueous solubility, low cost, and simple synthesis, and NCs‐based ratiometric fluorescent probes have attracted much attention. In this progress report, the preparation and properties of NCs and the design of ratiometric fluorescent probes are summarized. Sensing of a broad range of analytes including cations, gas, small molecules, macromolecules, temperature, and pH is discussed. In addition, the challenges and future directions for NCs‐based ratiometric fluorescent probes are also presented.     

Semiconducting Polymer Nanoparticles as Fluorescent Probes for Biological Imaging and Sensing

In recent years, semiconducting polymer nanoparticles have emerged as a new class of extraordinarily bright fluorescent probes. These polymer nanoparticles, which are primarily composed of π‐conjugated polymers, exhibit a variety of outstanding features, including exceptional fluorescence brightness, fast radiative rate, good photostability, facile surface functionalization, and low cytotoxicity. These advantageous characteristics make polymer nanoparticles highly promising for applications in biological imaging and sensing. This progress report highlights recent advances in the synthesis, characterization, and applications as bio‐labels or sensors of these highly emissive organic nanoparticles.     

Fiber Optic Spectroelectrochemical Sensing for in situ Determination of Metal Ions

In situ chemical sensing techniques are increasingly used for a variety of applications, including industrial process control, on‐site environmental assessment, and detection of explosives and chemical and biological weapons. A common category of sensors for such purposes entails the use of optical fibers for making spectral measurements of target compounds or species derived from these compounds via physical, chemical, enzymatic, or immunologic reactions. A less common but potentially advantageous approach involves the electrochemical conversion of the analyte subsequent to its spectroscopic detection. These spectroelectrochemical schemes represent versatile, essentially reagent‐free analyses that could provide superior alternatives to existing methods. Reported here is a summary of progress made by the authors' group toward the development of fiber optic spectroelectrochemical sensors for in situ measurements. The aqueous copper (II)/copper (0) couple was chosen as a model system to investigate the merit of an analytical scheme involving (i) cathodic preconcentration of Cu²⁺ as Cu⁰ followed by (ii) anodic stripping of Cu⁰ to Cu²⁺, (iii) complexation of Cu²⁺ by an appropriate ligand, and finally (iv) absorbance determination of the copper–ligand complex or fluorescence determination of the unbound ligand. Results are encouraging and indicate the need for further refinement of the sensor's design and the experimental protocol in order to improve the method's sensitivity.     

水溶性量子点荧光探针用于帕珠沙星的含量测定

文章采用荧光光谱和紫外光谱研究了CdTe量子点(CdTe QDs)与广谱抗菌药物帕珠沙星的相互作用。结果表明,随着帕珠沙星浓度的增加,CdTe QDs荧光强度有规律的降低,但通过透射电镜图对QDs及加入帕珠沙星后的QDs进行比较,发现QDs仍然均一单分散,表明反应的作用机理可能是帕珠沙星促使QDs表面键合的有机分子发生变化,在Cd空位表现出的表面缺损上形成了碲氧复合物,致使荧光猝灭。因此该反应可作为一种新颖的快速检测帕珠沙星含量的方法。在一定条件下,帕珠沙星溶液的浓度与量子点荧光强度成线性关系,线性范围为10.0～850 μg·mL-1,相关系数r为0.995 4,检测限(S/N=3)为3.254×10-3 μg·mL-1。药物对量子点的猝灭常数为2.188×104 L·mol-1。应用到冻干粉针剂和氯化钠注射液中帕珠沙星的含量测定,所得结果与标示量一致。该方法较常用检测方法具有简便、快捷、灵敏、线性范围宽的优点,并有望进一步开展发药物体内显像及作用机理的研究。     

高效荧光碳点的制备及其对金属离子的检测研究

采用氮和硫元素共掺杂的水热法合成了一种发蓝光的碳点.经过一系列的光学和微观结构表征分析,发现氮和硫元素可以通过杂原子掺杂和表面官能团的形式充分参与到碳点中,这决定了所制备的蓝光碳点拥有最高54.27%的量子产率.由于其高效荧光,该碳点可以用作传感探头检测金属离子,且对Ag+和Fe3+具有高灵敏度和选择性,通过Stern-Volmer方程拟合发现,随着离子浓度的变化,两种金属离子不同的淬灭机制和检测极限为在实践中有效检测和区分Ag+和Fe3+提供了一种可行的新方法.     

Quantum Dots Based Fluorescent Probe for the Selective Detection of Heavy Metal Ions

Journal of Fluorescence - Heavy metal ions are one of the primary causes of environmental pollution. A marshal effect of heavy metal ions is a paramount ultimatum to humans, aquatic animals and...     

Detection of Fe3+ and Hg2+ Ions by Using High Fluorescent Carbon Dots Doped With S And N as Fluorescence Probes

In this paper, carbon quantum dots (N-S-CDs) containing sulfur and nitrogen were synthesized using citric acid and thiourea. The average particle size of N-S-CDs is 8 nm. The N-S-CDs surface contains various of functional groups, which has good water solubility. The fluorescence quantum yield of N-S-CDs is as high as 36.8%. N-S-CDs emits strong blue fluorescence in aqueous solution and has good photostability in neutral and alkaline NaCl solution. N-S-CDs has unique selectivity and high sensitivity to Fe³⁺ and Hg²⁺ ions, and the lowest detection limits are 1.4 μM and 0.16 μM, respectively. Under the interference of other metal ions, Fe³⁺ and Hg²⁺ ions can still effectively and stably quench the fluorescence of N-S-CDs. In addition, in the detection of actual samples, N-S-CDs can effectively detect Fe³⁺ and Hg²⁺ ions in tap water and lake water.

     

Fluorescent Carbon Dots as Cost-Effective and Facile Probes for Caffeic Acid Sensing via a Fluorescence Quenching Process

Caffeic acid (CA), a familiar color stabilizing reagent, has aroused general concern due to its uncontrolled addition, and thus the detection of CA is increasingly important. In our report, the bright carbon dots (CDs) were prepared via hydrothermal treatment with urea and citric acid act as raw material and their characteristics were discussed through X-ray diffraction (XRD), transmission electron microscopy (TEM) and so on. Impressively, the strong emission of the as-prepared CDs (Quantum Yield: 24.3%) decreased sharply upon a full reaction with the added CA. Hence, we first present an improved strategy for determining CA based upon the quenching of the strong emission of CDs. In this strategy, 0.79–100.0 µmol L^??1 caffeic acid could be simply detected, and a detection limit of 0.24 µmol L^??1 was allowed. Additionally, CA in red wine samples can be successfully detected by this method and the exploration of the quenching mechanism of the CA-CDs system was done.     

Saccharide Sensing Using Gold and Silver Nanoparticles-A Review

We review new methodologies for glucose sensing from our laboratories based on the specific biological interactions between Con A, dextran-coated gold nanoparticles and glucose, and the interactions between dextran, glucose, and boronic-acid capped silver nanoparticles in solution. Our new approaches promise new tunable glucose sensing platforms. Dextran-coated gold nanoparticles were aggregated with the addition of Con A resulting in increase an in absorbance of nanoparticles at 650 nm, where the post-addition of glucose caused the dissociation of the aggregates and thus a decrease in the absorbance at 650 nm. The interaction of glucose and dextran with boronic acid-capped silver nanoparticles in solution resulted in enhanced luminescence intensity cumulatively due to surface-enhanced fluorescence and the decrease in absorbance at 400 nm, with an increase in absorbance at 640 nm. Lifetime measurements were used to distinguish the contribution from the surface-enhanced fluorescence. TEM was employed to assess the aggregation of nanoparticles.     

4-Hydroxycoumarin Derivatives in Micelles: An Approach to Detect a Structural Transition Using Fluorescent Viscosity Probes

The spectroscopic behavior of three coumarin derivatives was investigated in water and in different micellar media. In SDS, the fluorescence intensity of two of the dyes increased upon addition of sodium chloride. This effect was tentatively related to a sphere-to-rod transition occurring in the micelles.     

Fluorescent Recognition of Potassium and Calcium Ions Using Functionalised CdSe / ZnS Quantum Dots

Schiff base receptor 1a has been synthesised and attached to the surface of preformed CdSe/ZnS Quantum Dots (QDs) to form QD-conjugate 2a. While 1a was determined to be selective for Mg²⁺, 2a demonstrated selectivity for both K⁺ and Ca²⁺ when tested against a range of physiologically and environmentally relevant cations by changes in the fluorescence spectra. Thus, the nanoparticle surface functions as a scaffold for the organisation of receptors enabling semi-selective binding. The fluorescence response was shown to be linear between 15–50?μM for K⁺ and 2–35?μM for Ca²⁺. It was also demonstrated that 2a could measure both K⁺ and / or Ca²⁺ in solutions containing both ions.     

New Polymerizable Tetraaza Macrocycle Containing Two Acridine Units for Selective Fluorescence Sensing of Metal Ions

A new fluorescent bis(acridino)-macrocycle containing two allyl groups was synthesized and photophysically studied. Studies were carried out on metal ion recognition and selectivity-influencing effects including the determination of the relevant thermodynamic constants as logK and pK_a. The proposed sensor molecule is recommended for the development of Zn²⁺-selective optochemical analyzers based on covalently immobilized ionophores as it has a unique pH-independent metal ion recognition ability, which is not influenced by anions and other potentially occurring metal ions in biological samples.