等离激元增强荧光的纳米结构、机制及其应用

基于等离激元纳米材料具有优异的光学调控性能，综述了等离激元荧光增强的基本机理，分别阐述了具有特定功能的等离激元增强荧光的纳米结构(PEFNSs)的构效关系，包括等离激元纳米核的材料、形状、尺寸、等离激元纳米颗粒(PNP)与荧光物质间的距离以及荧光物质种类对荧光增强的影响，最后综述了PEFNSs在生物传感器、生物成像和光热疗法和光动力疗法等生物医学领域中的应用，且其在生物、物理、化学等领域的应用具有重要意义。     

用于生物成像的近红外小分子荧光探针的研究进展

小分子荧光探针具有灵敏度高、生物相容性好、样品损伤小等优点，在疾病相关的生物分子检测领域显示出巨大潜力。但是，大部分的荧光探针发射波长短、斯托克斯位移较小，限制了其在生物成像中的应用。近年来，越来越多具有较长波长的近红外荧光探针被开发出来，用于疾病相关的生物分子的成像检测。对不同结构的荧光探针进行分类讨论，系统介绍了以花菁、半花菁、氧杂蒽和氟硼吡咯染料为荧光团的近红外探针的研究进展，简要概述近红外小分子荧光探针在对生物分子识别过程中的作用原理和生物成像领域的应用，这对荧光探针的性能提升和未来发展提出新的研究思路。     

基于醛基取代的氟硼二吡咯类荧光母体探针的合成及其应用

荧光探针具有灵敏度高、可实时检测、精准诊断与成像可视化等优点，被广泛应用于生物医药、信息存储、化学分析等领域。氟硼二吡咯（BODIPY）类荧光探针因其优异的光物理化学特性而被广泛设计与开发使用。该文综述了醛基取代的BODIPY荧光探针的分子设计策略和功能化应用，包括α位醛基BODIPY、β位醛基BODIPY、meso位醛基BODIPY和1,7-位醛基BODIPY的不同位点醛基调控的BODIPY荧光母体探针及其在阴离子检测、生物硫醇识别及细胞成像方面的研究进展。设计新型的醛基取代BODIPY荧光探针将在精准诊疗上具有巨大的发展空间。     

试卤灵类光学探针的研究进展

光学探针是指与目标物质发生反应(包括配位、包合和基团反应等)并引起光学(吸光、荧光或发光)性质的变化,基于这些变化从而可对目标物质进行分析与测定的一类特殊试剂。光学探针不仅能改善分析的灵敏度,而且能大幅度提高对样品的时空分辨能力,因此,长期以来一直受到人们的关注。试卤灵为一性能优良的荧光体,特别是其7-羟基的取代作用通常会封闭光信号;这一特性近年引起了人们的兴趣,并被广泛用于构建具有低背景光信号的新型探针。本文将综述试卤灵类光学探针的发展及其在蛋白酶、离子、活性氧物种分析方面的应用,包括探针分子的构筑、检测机理以及生物成像等方面的研究。     

二芳基乙烯的发展与应用

光致变色是指化合物在一定波长和强度的光作用下分子结构发生可逆变化。二芳基乙烯相比于传统的光致变色分子具有良好的热稳定性和抗疲劳性,是目前最有应用前景的一类光致变色材料。本文归纳了二芳基乙烯具有的热稳定性和抗疲劳性的机理,并简述了其基于这些特性在光存储、分子开关、超分辨荧光成像以及分子机器领域的应用,同时对未来二芳基乙烯的发展方向作出展望。     

光学超分辨近场技术在光存储中的应用

超分辨近场结构技术是在传统的超分辨光盘技术和近场光学的基础上发展起来的新技术。本文介绍了超分辨近场结构技术的基本原理,综述了该技术在纳米光信息存储和光刻方面应用研究的最新进展,提出了存在的问题,展望了它的发展前景。     

荧光硫量子点制备及应用研究进展

硫量子点具有发光强度高、毒性低和光化学性能稳定等优势，广泛应用于细胞成像、光电转换和化学催化等领域。鉴于此，本文系统综述了硫量子点的合成方法，光学性能和应用背景。硫量子点的合成方法可分为“自下而上法”和“自上而下法”，对比发现“自上而下法”合成的硫量子点具有更高的荧光量子产率。分析了硫量子点的光学性质，表明其具有紫外吸收特性、荧光特性、光致发光、电化学发光以及光学稳定性。最后，系统介绍了硫量子点在荧光探针、生物成像以及发光器件等领域的重要应用。基于以上分析，深刻剖析了当下硫量子点在前沿应用中亟待解决的问题，展望了未来硫量子点在生物医学、光电催化等新行业、新领域的发展方向。     

基于醛基取代的氟硼二吡咯类荧光母体探针的合成及其应用

荧光探针具有灵敏度高、可实时检测、精准诊断与成像可视化等优点,被广泛应用于生物医药、信息存储、化学分析等领域。氟硼二吡咯(BODIPY)类荧光探针因其优异的光物理化学特性而被广泛设计与开发使用。该文综述了醛基取代BODIPY荧光团的分子设计策略和功能化应用,包括α位醛基-BODIPY、β位醛基-BODIPY、meso位醛基-BODIPY和1,7-位醛基-BODIPY的不同位点醛基调控的BODIPY荧光母体探针及其在阴离子检测、生物硫醇识别及细胞成像等方面的研究进展。设计新型的醛基取代BODIPY探针,未来在精准诊疗上具有发展空间。     

用于识别细菌的有机荧光探针研究进展

细菌感染已经成为威胁人类健康发展的重大疾病之一，导致了极高的死亡率和致残率。与此同时，随着细菌对抗生素耐药性的不断增加迫切需要新的设备来早期诊断和监测住院患者的深层次和复杂的细菌感染。荧光探针是一种具有高特异性和无创性的细菌可视化智能成像设备可以实现对于细菌感染的高特异性和无损性识别成像，本文对目前已有的用于细菌检测的荧光探针进行总结。在本文中，我们根据探针对细菌的识别机制将这些荧光探针分为两种不同的类型，包括与细菌独特成分共价结合的探针和细菌代谢标记的探针。这些探针不仅可以为细菌病原体相关疾病提供快速有效的诊断，而且可以加快新型抗生素的研发。     

席夫碱荧光探针对水系Zn2+的实时荧光标记与定量分析

为了实现水系Zn2+的实时检测与定量分析,设计以水杨醛苯甲酰腙作为Zn2+识别基团,引入具有特征性吸收的C=N键作为荧光发色团,合成得到一类新型席夫碱Zn2+荧光探针.通过IR、1H NMR、MS表征探针结构,采用FS分析探针光学性质、探针-Zn2+特异性识别和水系探针-Zn2+荧光标记性能.结果显示,该荧光探针能够特异性识别Zn2+,具有快速响应、光学信号稳定等优势,可用于水系Zn2+的定性检测和定量分析.在体外ECV304细胞荧光共聚焦显微成像实验中,细胞形态完整且荧光成像效果良好,说明探针对Zn2+的荧光标记产物具有较好的透膜性与低毒性,具有进一步应用于生命体中Zn2+标记示踪的前景.     

An Efficient Aequorea victoria Green Fluorescent Protein for Stimulated Emission Depletion Super-Resolution Microscopy

In spite of their value as genetically encodable reporters for imaging in living systems, fluorescent proteins have been used sporadically for stimulated emission depletion (STED) super-resolution imaging, owing to their moderate photophysical resistance, which does not enable reaching resolutions as high as for synthetic dyes. By a rational approach combining steady-state and ultrafast spectroscopy with gated STED imaging in living and fixed cells, we here demonstrate that F99S/M153T/V163A GFP (c3GFP) represents an efficient genetic reporter for STED, on account of no excited state absorption at depletion wavelengths <600 nm and a long emission lifetime. This makes c3GFP a valuable alternative to more common, but less photostable, EGFP and YFP/Citrine mutants for STED imaging studies targeting the green-yellow region of the optical spectrum.     

Green-Emitting Rhodamine Dyes for Vital Labeling of Cell Organelles Using STED Super-Resolution Microscopy

Fluorescence microscopy reveals the localization, spatial distribution, and temporal dynamics of the specifically labeled organelles in living cells. Labeling with exogenous conjugates prepared from fluorescent dyes and small molecules (ligands) is an attractive alternative to the use of fluorescent proteins, but proved to be challenging due to insufficient cell-permeability of the probes, unspecific staining, or low dye brightness. We evaluated four green-emitting rhodamine dyes and their conjugates intended for the specific labeling of lysosomes, mitochondria, tubulin, and actin in living cells. The imaging performance of the probes in living human fibroblasts has been studied by using confocal and stimulated emission depletion (STED) super-resolution microscopy with a commercial 595 nm STED laser. Two bright and photostable dyes (LIVE 510 and LIVE 515) provide specific and versatile staining.     

Amplified Expansion Stimulated Emission Depletion Microscopy

Expansion microscopy (ExM) enhances spatial resolution by using a swellable polymer that expands the sample volume by a factor of ≈4 in one dimension and a factor of ≈64 in volume. Combining ExM with stimulated emission depletion (STED) microscopy, referred to as ExSTED, increases the resolution to up to 10 nm. However, photobleaching is a critical issue in ExSTED because the sample expansion lowers the fluorophore density whereas high-resolution STED requires high depletion intensity. To overcome these issues, we developed extremely bright expansion nanoscopy by using biotin–avidin signal amplification to increase the labeling density. Our method provides up to sevenfold increases in fluorescence signal intensity in expanded samples, thus enabling the use of STED imaging with maximum depletion intensities of a commercial microscope in the order of GW cm⁻². We demonstrated the method by using biotinylated antibodies and genetic incorporation approaches that allow localization of biotin in a specific molecule or organelle.     

Optimized fluorescent trimethoprim derivatives for in vivo protein labeling

The combined technologies of optical microscopy and selective probes allow for real-time analysis of protein function in living cells. Synthetic chemistry offers a means to develop specific, protein-targeted probes that exhibit greater optical and chemical functionality than the widely used fluorescent proteins. Here we describe pharmacokinetically optimized, fluorescent trimethoprim (TMP) analogues that can be used to specifically label recombinant proteins fused to E. coli dihydrofolate reductase (eDHFR) in living, wild-type mammalian cells. These improved fluorescent tags exhibited high specificity and fast labeling kinetics, and they could be detected at a high signal-to-noise ratio by using fluorescence microscopy and fluorescence-activated cell sorting (FACS). We also show that fluorescent TMP-eDHFR complexes are complements to green fluorescent protein (GFP) for two-color protein labeling experiments in cells.     

Fluorescent,Recombinant-Protein-Conjugated,Near-Infrared-Emitting Quantum Dots for in Vitro and in Vivo Dual-Color Molecular Imaging

Near-infrared (NIR)-emitting fluorescent probes are widely used for molecular imaging at the whole-body level. However, NIR-emitting fluorescent probes emitting over λ=700 nm are not suitable for molecular imaging at the cellular level, because most of the conventional fluorescence microscopes have very low optical sensitivity in the NIR region. Thus, to achieve fluorescence imaging at the cellular and whole-body levels by using single probes, visible and NIR-emitting dual-color fluorescent probes are desirable. For dual-color fluorescence molecular imaging, we synthesized fluorescent, recombinant-protein-conjugated, NIR-emitting quantum dots (QDs), in which the recombinant protein consists of enhanced green fluorescent protein (EGFP) and the immunoglobulin binding domain (B1) of protein G. This dual-color fluorescent QD probe binds the Fc region of immunoglobulin G (IgG) through its B1 domain at the QD surface and acts as a molecular-imaging probe at both the cellular and whole-body levels. In this paper, we present the synthesis of fluorescent, recombinant protein (HisEGFP-GB1)-conjugated, NIR-emitting QDs and their application to the dual-color molecular imaging of breast cancer cells in vitro and in vivo.     

Fluorescein Derivatives as Fluorescent Probes for pH Monitoring along Recent Biological Applications

Potential of hydrogen (pH) is one of the most relevant parameters characterizing aqueous solutions. In biology, pH is intrinsically linked to cellular life since all metabolic pathways are implicated into ionic flows. In that way, determination of local pH offers a unique and major opportunity to increase our understanding of biological systems. Whereas the most common technique to obtain these data in analytical chemistry is to directly measure potential between two electrodes, in biological systems, this information has to be recovered in-situ without any physical interaction. Based on their non-invasive optical properties, fluorescent pH-sensitive probe are pertinent tools to develop. One of the most notorious pH-sensitive probes is fluorescein. In addition to excellent photophysical properties, this fluorophore presents a pH-sensitivity around neutral and physiologic domains. This review intends to shed new light on the recent use of fluorescein as pH-sensitive probes for biological applications, including targeted probes for specific imaging, flexible monitoring of bacterial growth, and biomedical applications.     

反应激活型酶荧光探针的研究进展

酶在维持生物体内稳态与生命活动的正常运行方面发挥着举足轻重的作用。某些特定酶含量及活性的异常与人类重大疾病的发生与发展密切相关。因此,生物体内特定酶的实时原位检测及可视化成像具有重要的意义。化学荧光探针具有选择性好、灵敏度高及高时空分辨率可视化成像等优点,近年来研究者设计合成了大量的可用于生物体系内酶识别与可视化成像的荧光探针。目前识别酶的荧光探针主要有两类：（1）基于酶对荧光探针分子中酶抑制剂基团的识别引起探针荧光信号的变化;（2）基于酶对荧光探针特异性催化反应来实现识别前后荧光信号的激活,称为反应激活型酶荧光探针。对反应激活型酶荧光探针的设计策略及4种重大疾病相关的生物标志酶（单胺氧化酶、β-半乳糖苷酶、硝基还原酶、γ-谷氨酰转肽酶）的识别可视化荧光探针研究进展进行了综述,对未来酶识别荧光探针的研究方向进行了展望。     

Small‐Protein‐Stabilized Semiconductor Nanoprobe for Targeted Imaging of Cancer Cells

Recently, semiconductor nanoparticles such as quantum dots (QDs) have attracted significant attention for bioimaging. Complex chemical functionalization, surface modification, and bioconjugation chemistry are generally required to tag biomolecules to QDs for imaging of different biomarkers. In this study, we report a simple method for production of QDs stabilized by the small protein, Affibody (AF‐QDs) for fluorescent imaging of the human epidermal growth factor receptor type 2 (HER2) in human A549 lung cancer cells. This one‐pot synthesis of AF‐QDs avoids complex chemical conjugation procedures and demonstrates a promising approach for the preparation of fluorescent nanoprobes for imaging of cancer targets.     

Reaction-based AIE-active Fluorescent Probes for Selective Detection and Imaging

Fluorescent probes have been widely investigated for their features of rapid response, easy operation and high sensitivity. Among them, reaction-based fluorescent probes, for their unique reaction-based nature, guarantee them with excellent selectivity, effectively avoiding the possible interference from other chemical and biological species in physiological environment. Conventional reaction-based fluorescent probes are aggregation-caused quenching (ACQ) fluorophores. The application of these kinds of probes are limited for their poor photostability and narrow Stokes shifts. Compared with ACQ fluorophores, aggregation-induced emission (AIE) fluorophores become emissive in aggregation states with higher signal-to-noise ratio, better photostability and larger Stokes shifts. In this review, we summarize the latest developed reaction-based AIE-active probes, including the design principle and application in various sensing systems and give an outlook for the future development of this kind of promising fluorescent probes.