近红外荧光染料的结构、性质及生物荧光成像应用

近红外荧光生物成像技术由于具有深的组织穿透性、低背景荧光干扰、最小生物样本光损伤等特点引起人们越来越多的关注。开发高荧光效率、低毒性的近红外荧光染料是近红外荧光成像技术发展的关键所在。本文综述了五类主要的有机近红外荧光染料(菁类、BODIPY类、罗丹明类、方酸类、卟啉类)的研究进展,重点分析其结构与光学性质等构效关系,为近红外荧光染料的设计和制备提供指导。另外,总结了有机近红外荧光材料功能化修饰的主要方法以改善生物相容性、靶向性能等,最后对近红外荧光染料存在的主要问题以及未来的热点方向进行了分析和展望。     

异元素掺杂碳点的制备及其在生物成像中的应用

荧光碳点具有良好的生物相容性和优良的抗光漂白能力,因此碳点在生物荧光成像方面的应用潜力受到广泛关注,但是碳点相对较低的荧光量子产率和缺乏近红外荧光发射的缺陷限制了碳点在荧光成像分析中的应用.随着异元素掺杂对碳点结构和荧光性质的改善,碳点被越来越广泛地用于生物成像.本文对近年来元素掺杂碳点的合成方法、异元素掺杂对碳点光学性质的影响和元素掺杂碳点在成像分析中的进展进行了综述,并对其应用前景进行了展望.     

水相一步法合成具有双光子效应的高效橙红荧光聚合物碳点

聚合物碳纳米点是近年来新兴的一种荧光纳米探针,具有较低的生物毒性、良好的水溶性、较高的量子产率、优异的光/化学稳定性以及良好的生物相容性.目前所制备的碳点大都表现出蓝、绿色荧光发射.为实现碳点长波荧光发射,扩大其在生物标记与成像及光电显示方面的应用,本文采用水相一步法交联聚合反应制备了具有橙红荧光发射性质且具有双光子效应的聚合物碳点,发射波长为604 nm,荧光量子产率达到30.64%,并且应用在生物活体成像中.     

基于硅杂蒽类染料的荧光探针及其应用

近年来,荧光成像技术为人们研究活体细胞及组织内的化学生物学过程提供了有效的研究工具,可以无损、实时、原位地以高时空分辨率实现对目标物进行生物荧光成像与分析。荧光成像技术在生物学、环境监测、临床诊断和药物发现等诸多研究领域发挥着越来越重要的作用。生物荧光成像技术的最新进展对发展新型小分子荧光染料及探针提出了更高的要求。激发和发射波长位于近红外光区（600~900 nm）的荧光染料及探针由于具有光毒性低、生物分子自发荧光干扰小、光散射低、组织穿透能力强等优点,非常适合用于生物荧光成像领域。通过将罗丹明分子中O桥原子用Si代替,得到了一类新型的探针分子--硅杂蒽类荧光探针。这类染料分子在保留了氧杂蒽荧光染料优越的光学性质的同时,光谱发生明显红移,满足了近红外荧光检测的要求,具有良好的生物相容性。本文综述了近年来基于硅杂蒽及其衍生物荧光探针的合成及在金属离子、pH值、小分子、生物酶等检测方面的研究进展,并且简要阐述了基于硅杂蒽类探针分子的识别检测机理以及其在生物成像等方面的应用。     

荧光碳点探针的合成、性质及其在生物成像中的应用

荧光碳点探针是近几年来发展起来的一种新型荧光探针，具有传统有机染料、荧光染色蛋白及一般荧光纳米材料无法比拟的独特优势，如具有良好的水溶性、化学惰性、低毒性、易于功能化、抗光漂白性、可调谐和生物相容性等优异性能，因而引起研究者的广泛关注。目前已发展水热法等近十种较为经济便捷的方法，可进行大规模的荧光碳点制备，在细胞功能研究及细胞表面和内部功能分子的探测、组织的成像、病菌的定位等方面得到了较为广泛的应用。笔者对近年来荧光碳点的合成方法、依赖于碳点尺寸和波长等性质的发光性能，以及荧光碳点在生物成像等方面的应用作一简要综述，并对其在药用植物病理方面的应用提出展望，期望为丰富荧光碳点在生物成像领域的应用提供一定的借鉴和参考。     

双光子荧光探针研究及其应用*

双光子荧光显微成像兼具诸如近红外激发、暗场成像、避免荧光漂白和光致毒、定靶激发、高横向分辨率与纵向分辨率、降低生物组织吸光系数及降低组织自发荧光干扰等特点而显著地优于单光子荧光显微成像,为生命科学研究提供了更为锐利的工具。而用于像离子的含量及其对生理的影响、离子参与的生理活动机制、离子与分子的作用、特定分子的分布及其相互作用等方面研究的双光子荧光探针,是实现成像的关键。双光子荧光探针的研究旨在促进双光子荧光显微镜应用的发展,促进生命科学、医学科学的快速发展,同时也带动双光子荧光探针所隶属的化学这一学科的发展。因此对双光子荧光探针的研究具有重要的理论和实践意义。该文综述了双光子荧光显微成像的优点、双光子荧光探针设计的原理及双光子荧光探针在离子分析方面的应用,并展望了这类荧光探针的发展趋势与应用前景。     

双光子荧光探针

双光子吸收是指在强光激发下,介质分子同时吸收两个光子,从基态跃迁到两倍光子能量的激发态的过程。荧光显微成像是研究活体生物的重要工具,而最通常的细胞成像方法则是使用单光子激发荧光团的单光子显微成像。近红外光源激发的双光子荧光探针克服了单光子荧光探针的光漂白与光致毒而更适于生物检测与成像,为生命科学研究提供了更为锐利的工具。双光子荧光探针的作用机理包括分子内电荷迁移(ICT)、荧光共振能量迁移(FRET)、光诱导电子迁移(PET)与基团转换(GC) 4种方式。该文综述了双光子阳离子探针(Mg²⁺, Ca²⁺, Pb²⁺, Hg²⁺, Ag⁺, Fe³⁺, Zn²⁺, Na⁺, Cr³⁺)、双光子阴离子探针(F^-)、pH探针、双光子葡萄糖示踪器、双光子脂筏探针、双光子巯基探针、双光子半胱氨酸探针和双光子生物标记探针,以及双光子荧光探针在生物成像方面的应用,展望了双光子荧光探针的发展趋势与应用前景。     

稀土纳米材料在高分辨活体成像及诊疗中的应用

荧光成像具有时空分辨率高、 反馈快、 非侵入和无电离辐射等优点, 是一种重要的生物成像技术. 与传统用于荧光成像的可见光和近红外一区(NIR-I, 600~950 nm)相比, 近红外二区(NIR-Ⅱ, 1000~1700 nm)窗口具有低生物组织散射系数和低生物自发荧光, 采用NIR-Ⅱ光进行活体荧光成像能有效提高成像的分辨率、 信噪比和穿透深度. 稀土纳米颗粒(RENPs)具有大斯托克斯位移、 高化学稳定性、 可调的荧光寿命以及较窄的发射带, 是一种重要的荧光成像探针. 近年来, 一系列具有优异的NIR-Ⅱ发光性能的稀土纳米材料被用于高分辨活体荧光成像. 本文综合评述了近年来RENPs用于高分辨活体成像及诊疗中的研究进展, 概述了RENPs的掺杂调控、 基质晶格选择和复合敏化等NIR-Ⅱ发光增强策略, 介绍了其在多种生物医学场景中的靶向聚集、 荧光传感和疾病治疗等功能, 并总结了其在多路成像、 多模态成像和疾病诊疗中的应用. 最后, 简要分析了RENPs在未来生物医学应用中面临的挑战和发展的方向.     

近红外二区荧光探针在生物成像领域的研究进展

荧光技术具有操作简便、分辨率高且可实现实时成像等特点,已被广泛应用于生物医学检测和成像领域,其中,近红外二区荧光染料(NIR-Ⅱ,10001700 nm)由于其发射波长较长,光散射和组织自发荧光干扰较少,在生物组织成像中具有更高的时空分辨率和更深的成像深度。 本文主要介绍了基于近红外二区荧光探针的设计原理及其在生物成像领域的研究现状,并对其发展作了进一步展望。     

基于聚集诱导发光荧光探针的细胞成像研究进展

荧光探针是化学传感技术领域在20世纪末的一项重大发现,具有合成简单、灵敏度高、选择性好、响应时间短、可视化高等优点。 将具有聚集诱导发光现象(AIE)特征的荧光基团与具有生物相容性的高分子结合起来,使得荧光材料具有毒性低、光稳定性好、生物相容性好等特点。 在分子、离子检测和细胞成像技术中得到广泛的研究和应用。 本文综述了细胞质成像、细胞膜成像、线粒体成像、溶酶体成像、脂滴成像、细胞核成像、细胞核和线粒体双靶向性成像的荧光探针,并对其应用前景做了展望。     

核酸适配体荧光探针在生化分析和生物成像中的研究进展

核酸适配体是指通过体外筛选技术从核酸文库中筛选出来,能够高特异性、高亲和力识别靶标物的寡核苷酸序列,具有靶标类型广泛、合成简单、相对分子质量小、化学稳定性高、易于进行生物化学修饰等优点。 核酸适配体能够通过折叠成特定的二维或三维构型与靶标物特异性结合,加上合适的信号转导机制,为重要靶标物的研究提供理想的分子识别与分子检测探针。 荧光检测技术具有高灵敏、高分辨率、易于实现多元分析等优点。 将核酸适配体的分子识别特性与荧光优异的光学检测性能相结合,在生命科学研究领域有着广泛的应用空间。 本文主要综述了核酸适配体荧光探针常见的分子设计和信号响应方式,及其在细胞成像、亚细胞成像中的应用研究,并对核酸适配体探针目前面临的一些挑战进行了讨论,最后对其未来的发展方向进行了展望。     

Label-free fluorescence detection in capillary and microchip electrophoresis

Herein, we summarize the current status of native fluorescence detection in microchannel electrophoresis, with a strong focus on chip-based systems. Fluorescence detection is a powerful technique with unsurpassed sensitivity down to the single-molecule level. Accordingly fluorescence detection is attractive in combination with miniaturised separation techniques. A drawback is, however, the need to derivatize most analytes prior to analysis. This can often be circumvented by utilising excitation light in the UV spectral range in order to excite intrinsic fluorescence. As sensitive absorbance detection is challenging in chip-based systems, deep-UV fluorescence detection is currently one of the most general optical detection techniques in microchip electrophoresis, which is especially attractive for the detection of unlabelled proteins. This review gives an overview of research on native fluorescence detection in capillary (CE) and microchip electrophoresis (MCE) between 1998 and 2008. It discusses material aspects of native fluorescence detection and the instrumentation used, with particular focus on the detector design. Newer developments, featured techniques, and their prospects in the future are also included. In the last section, applications in bioanalysis, drug determination, and environmental analysis are reviewed with regard to limits of detection.     

Optimization of dye-doped silica nanoparticles prepared using a reverse microemulsion method

Fluorescent labeling based on silica nanoparticles facilitates unique applications in bioanalysis and bioseparation. Dye-doped silica nanoparticles have significant advantages over single-dye labeling in signal amplification, photostability and surface modification for various biological applications. We have studied the formation of tris(2,2'-bipyridyl)dichlororuthenium(II) (Ru(bpy)) dye-doped silica nanoparticles by ammonia-catalyzed hydrolysis of tetraethyl orthosilicate (TEOS) in water-in-oil microemulsion. The fluorescence spectra, particle size, and size distribution of Ru(bpy) dye-doped silica nanoparticles were examined as a function of reactant concentrations (TEOS and ammonium hydroxide), nature of surfactant molecules, and molar ratios of water to surfactant (R) and cosurfactant to surfactant (p). The particle size and fluorescence spectra were dependent upon the type of microemulsion system chosen. The particle size was found to decrease with an increase in concentration of ammonium hydroxide and increase in water to surfactant molar ratio (R) and cosurfactant to surfactant molar ratio (p). This optimization study of the preparation of dye-doped silica nanoparticles provides a fundamental knowledge of the synthesis and optical properties of Ru(bpy) dye-doped silica nanoparticles. With this information, these nanoparticles can be easily manipulated, with regard to particle size and size distribution, and bioconjugated as needed for bioanalysis and bioseparation applications.     

Capillary electrophoresis-mass spectrometry, an attractive tool for drug bioanalysis and biomarker discovery

The coupling of CE with MS detection, a relatively recent hyphenated technique, has gained increasing respect in the field of bioanalytical applications over the past few years. The first part of this review presents CE-MS applications dealing with drug bioanalysis, including forensic analysis and metabolism studies. Practical considerations to achieve a robust and sensitive CE-MS coupling are also presented. It is indeed essential to strictly control some critical electrospray parameters, such as the sheath liquid composition and flow rate, the nebulizing gas pressure as well as the capillary outlet position. The second part of the review critically describes the applications of CE coupled on-line to MS for the identification of biomarkers in body fluids for diagnostic purposes. Since the sample preparation procedures strongly differ according to the intended use (drug bioanalysis or biomarker discovery), they are discussed separately, taking into account the particular properties of plasma and urine matrices.     

Recent advances in surface plasmon resonance based techniques for bioanalysis

Surface plasmon resonance (SPR) is a powerful and versatile spectroscopic method for biomolecular interaction analysis (BIA) and has been well reviewed in previous years. This updated 2006 review of SPR, SPR spectroscopy, and SPR imaging explores cutting-edge technology with a focus on material, method, and instrument development. A number of recent SPR developments and interesting applications for bioanalysis are provided. Three focus topics are discussed in more detail to exemplify recent progress. They include surface plasmon fluorescence spectroscopy, nanoscale glassification of SPR substrates, and enzymatic amplification in SPR imaging. Through these examples it is clear to us that the development of SPR-based methods continues to grow, while the applications continue to diversify. Major trends appear to be present in the development of combined techniques, use of new materials, and development of new methodologies. Together, these works constitute a major thrust that could eventually make SPR a common tool for surface interaction analysis and biosensing. The future outlook for SPR and SPR-associated BIA studies, in our opinion, is very bright. Surface plasmon resonance (SPR) is a powerful and versatile spectroscopic method for biomolecular interaction analysis (BIA) and has been well reviewed in previous years. This updated 2006 review of SPR, SPR spectroscopy, and SPR imaging explores cutting-edge technology with a focus on material, method, and instrument development. A number of recent SPR developments and interesting applications for bioanalysis are provided. Three focus topics are discussed in more detail to exemplify recent progress. They include surface plasmon fluorescence spectroscopy, nanoscale glassification of SPR substrates, and enzymatic amplification in SPR imaging. Through these examples it is clear to us that the development of SPR-based methods continues to grow, while the applications continue to diversify. Major trends appear to be present in the development of combined techniques, use of new materials, and development of new methodologies. Together, these works constitute a major thrust that could eventually make SPR a common tool for surface interaction analysis and biosensing. The future outlook for SPR and SPR-associated BIA studies, in our opinion, is very bright.      

金纳米簇的制备及其在生物医学中的应用

金纳米簇由几个到几十个金原子组成,具有尺寸小、荧光性能好、无毒等优点,被广泛应用于生物医学领域。本文介绍了包括模板法,刻蚀法,可逆相转移法和动力学控制法等金纳米簇的主要制备方法,并综述了金纳米簇在生物医学上的主要应用,包括生物检测、荧光成像和药物控释。     

离子色谱技术的重要进展和我国近年的发展概况

介绍了离子色谱技术近年的几项重要进展,包括Reagent-Free离子色谱系统,简易阀切换技术,弱电离有机酸的高灵敏分析,快速分析色谱柱,与前处理技术、电感耦合等离子体质谱和氢化物发生-原子荧光光谱联用,在生物医药分析中的应用等;并概述了近年来我国离子色谱在硬件技术研发、仪器检定规范的修改、标准方法和药典修订等方面的进展。     

Cover Picture: Nanomaterials for Fluorescence and Multimodal Bioimaging (Chem. Rec. 3/2023)

Bioconjugated nanomaterials replace molecular probes in bioanalysis and bioimaging in vitro and in vivo. Nanoparticles of silica, metals, semiconductors, polymers, and supramolecular systems, conjugated with contrast agents and drugs for image-guided (MRI, fluorescence, PET, Raman, SPECT, photodynamic, photothermal, and photoacoustic) therapy infiltrate into preclinical and clinical settings. Small bioactive molecules like peptides, proteins, or DNA conjugated to the surfaces of drugs or probes help us to interface them with cells and tissues. Nevertheless, the toxicity and pharmacokinetics of nanodrugs, nanoprobes, and their components become the clinical barriers, underscoring the significance of developing biocompatible next-generation drugs and contrast agents. This account provides state-of-the-art advancements in the preparation and biological applications of bioconjugated nanomaterials and their molecular, cell, and in vivo applications. It focuses on the preparation, bioimaging, and bioanalytical applications of monomodal and multimodal nanoprobes composed of quantum dots, quantum clusters, iron oxide nanoparticles, and a few rare earth metal ion complexes.     

4-[4-((4-吡啶基)乙烯基)苯乙烯基]-N,N-二正丁基苯胺的合成及光电性质研究

本文报道了4-[4-((4-吡啶基)乙烯基)苯乙烯基]-N,N-二正丁基苯胺的合成及晶体结构,并讨论了它的吸收光谱、荧光光谱、荧光寿命、荧光量子产率及电致发光性质.该分子晶体属于三斜晶系, P-1空间群,晶胞参数为:a=1.0101(3) nm, b=1.0352(2) nm, c=2.6220(5) nm, Z=4, V=2.4224(10) nm³, R₁=0.1006, wR₂=0.1818.研究结果表明,该化合物在电致发光方面有潜在的应用价值.CCDC号:815101.     

Synthesis and Photophysics of Core‐Substituted Naphthalene Diimides: Fluorophores for Single Molecule Applications

The synthesis and photophysics of two new aminopropenyl naphthalene diimide (SANDI) dyes are reported. A general and convenient method for the synthesis of the precursor mono‐, di‐, and tetrabrominated 1,4,5,8‐naphthalene tetracarboxylic dianhydrides is described. The two core‐substituted SANDIs exhibit many of the photophysical properties required for fluorescence labeling applications including high photostability and high fluorescence quantum yields (>0.5) in the visible region of the spectrum. The emission wavelength is sensitive to the number of substituents on the NDI core, and the fluorescence decay times are in the range of ～8–12 ns for both compounds in the solvents investigated. Preliminary fluorescence emission data from single molecules of the compounds embedded in poly(methyl methacrylate) films are also reported and show that single molecules have very low yields of photobleaching, particularly the di‐substituted system. Furthermore, only a small proportion (<10 %) of the single molecules studied display fluorescence intermittencies or “blinks” in their photon trajectory. The compounds appear to be excellent candidates for applications at the single molecule level, for example, as FRET labels.