基因编码荧光探针的构建与应用

基因编码荧光探针能够可视化探测活细胞中多种分析物及其相关分子事件,已成为细胞生物学等生命科学研究的强大分子工具.本文介绍了基因编码荧光探针的类型和主要应用场景,归纳了现有探针的优点和存在的问题,并对其未来发展进行了展望.     

基于有机小分子的Zn2+/Cd2+荧光探针研究新进展

综述了近年来基于有机小分子的Zn2+/Cd2+荧光探针研究新进展.总结了探针分子设计中受体R结构对检测Zn2+/Cd2+的影响,介绍了同一荧光探针分子对Zn2+/Cd2+分别检测的原理和应用.对未来Zn2+/Cd2+荧光探针的研究进行了展望.     

基于喹啉单元的荧光探针的研究进展

喹啉及其衍生物是一种很好的金属螯合剂,而且它们具有良好的荧光性能,所以喹啉及其衍生物一直是荧光探针领域研究的热点.本文综述了近几年来含喹啉单元的荧光探针的研究进展,介绍了含喹啉单元类的荧光探针对Zn~(2+)、Cd~(2+)、Al~(3+)、Fe~(3+)、Cu~(2+)和含喹啉单元与金属离子的复合型荧光探针对阴离子荧光传感性能,并展望了含喹啉单元的荧光探针的理论和应用前景.     

汞离子荧光探针的研究进展

综述了近几年来用于检测汞离子的荧光探针的研究进展,重点介绍了以氟硼二吡咯(BODIPY)、罗丹明、1,8-萘酰亚胺作为荧光团的汞离子荧光探针的结构和设计原理,概述了这些汞离子荧光探针在检测过程中的优点,并展望了这些汞离子荧光探针的研究和发展方向.     

乏氧激活荧光探针设计、合成及应用研究进展

介绍了肿瘤细胞的乏氧情况以及常规的肿瘤细胞乏氧检测手段,然后分别从荧光探针的设计构成、荧光探针的识别机理以及荧光探针的应用等方面对乏氧激活荧光探针进行了描述和总结,概述了构成荧光探针的常用荧光团,并详细探讨了构成荧光探针的乏氧靶向基团及其应用,重点介绍了硝基类和偶氮类两类乏氧感应基团,为新型荧光探针的设计合成提供了指引思路,提供了一种更高效、精准的肿瘤细胞的乏氧检测方法。     

新型荧光双重敏感响应性壳聚糖衍生物的合成及其发光性能研究

为了开发新型多功能天然高分子荧光材料,合成出一种新型含有环氧丙氧基荧光素(EPF)基团的水溶性壳聚糖衍生物GCS-EPF, 并用IR,1H NMR,UV光谱和荧光光谱等手段进行结构和发光性能的研究. 结果表明, 修饰后水溶性壳聚糖(GCS)的水溶液、 固体粉末和薄膜在520 nm附近具有较强的荧光发射, 其荧光强度不仅在0-60 ℃时对度有较快敏感响应, 同时在pH=0-13.5时对pH也有较快敏感响应, 具有双重敏感响应, 因此可将其作为温度荧光探针和pH荧光探针的高分子材料.     

多肽荧光探针在蛋白质检测中的应用

荧光探针法是痕量蛋白质检测的重要方法,其中多肽荧光探针得到了广泛的应用.本文综述了3种主要类型多肽荧光探针,即单荧光标记探针、双荧光标记探针和与其他材料形成复合物的探针的结构特点、检测原理以及不同类型多肽荧光探针在蛋白质定性、定量检测和酶活性测定等方面的应用,并对多肽荧光探针的未来发展方向进行了展望.     

缺氧响应荧光探针的成像及治疗应用

由于肿瘤内部细胞远离血管, 其氧气消耗量远远超出血液供应量, 因此容易导致肿瘤缺氧. 肿瘤缺氧会引发肿瘤扩散加速、 诱导某些基因过表达及产生药物抗药性等问题. 基于此, 发展性能优异的缺氧响应荧光探针对肿瘤的诊断和治疗具有重要意义. 本文对缺氧响应荧光探针在成像及治疗方面的应用进展进行了综合评述, 介绍了硝基、 偶氮键和醌3种常用的缺氧响应基团, 并探讨了它们在缺氧微环境下的识别机理; 介绍了缺氧响应荧光探针的构建及其在生物成像方面的最新研究成果; 总结了缺氧响应荧光探针在基因治疗、 光动力学治疗、 化学治疗及协同治疗方面的研究进展; 展望了缺氧响应荧光探针在临床诊断和治疗方面的应用前景.     

超痕量分析中的激光诱导荧光检测

本文对激光诱导荧光检测器(LIF-D)及其主要器件激光器、滤光片、透镜、光电检测器、荧光探针及扫描装置的现状和发展趋势作了综述,介绍了LIF在单分子检测中的应用.     

有序组装型荧光小分子探针及其生物成像应用研究进展

基于小分子探针的荧光成像分析具有灵敏度高、操作简便、响应速度快、样本损伤小和时空分辨率高等优势,是在细胞和活体水平获取生化信息的有力手段.其中,有序组装型小分子荧光探针以其独特的组装方式和识别模式,表现出比传统小分子荧光探针更优异的成像性能(如抗扩散能力强、成像对比度高、光稳定性好以及环境干扰小等),从而引起研究工作者的广泛关注.本文总结了几类常见的有机染料聚集体及相应小分子荧光探针在生物成像领域的应用.随后,着重介绍了以2-(2-羟基苯基)-4(1H)-喹唑啉酮(HPQ)及其衍生物为代表的氢键驱动有序组装的有机染料组装体的设计、优化策略及其在生物医学领域应用中的最新进展.最后,对有序组装型荧光小分子探针在设计和应用方面存在的问题进行了讨论,为新型有序组装型荧光小分子探针的设计提供了思路.     

Bioorthogonal Turn‐On Probe Based on Aggregation‐Induced Emission Characteristics for Cancer Cell Imaging and Ablation

Bioorthogonal turn‐on probes have been widely utilized in visualizing various biological processes. Most of the currently available bioorthogonal turn‐on probes are blue or green emissive fluorophores with azide or tetrazine as functional groups. Herein, we present an alternative strategy of designing bioorthogonal turn‐on probes based on red‐emissive fluorogens with aggregation‐induced emission characteristics (AIEgens). The probe is water soluble and non‐fluorescent due to the dissipation of energy through free molecular motion of the AIEgen, but the fluorescence is immediately turned on upon click reaction with azide‐functionalized glycans on cancer cell surface. The fluorescence turn‐on is ascribed to the restriction of molecular motion of AIEgen, which populates the radiative decay channel. Moreover, the AIEgen can generate reactive oxygen species (ROS) upon visible light (λ=400–700 nm) irradiation, demonstrating its dual role as an imaging and phototherapeutic agent.     

Optical Properties and Response Mechanism Analysis of Multi-branched Fluorescent Probes Based on Intramolecular Charge Transfer

In this work, the optical properties of fluorescent probes used for detection of biothiol were studied by employing time-dependent density functional theory. By calculating the single photon absorption and emission properties of probe Mol.1, Mol.2 and Mol.3 before and after reaction with cysteine and homocysteine, we have investigated the effect of carboncarbon triple bond and benzene ring on the properties of fluorescent probes. It is found that the oscillator strength of probe molecules increases gradually with the improvement of the structure of the electron donor triphenylamine and the addition of carbon-carbon triple bonds, and better properties of fluorescence probes have also been demonstrated. At the same time, the effect of different number of side branches on the molecular properties of the probe was also studied. The results showed that compared with single-branched molecule Z1 and tribranched probe Mol.3, two side probe molecules Z2 had higher oscillator strength andbetter detection effect. In addition, the new single-branched probe Mol.4 with the addition of carbon-carbon triple bonds and benzene rings has better probe properties and simpler structure than the tribranched probe Mol.3.     

氟硼二吡咯类pH荧光探针PET光谱特性的理论计算

氟硼二吡咯(BODIPY)类pH荧光探针分子是基于光诱导电子转移(PET)的荧光探针分子, 识别基团氮原子上引入不同取代基可呈现不同的光学灵敏度. 本文应用密度泛函理论(DFT)及含时密度泛函理论(TD-DFT)方法对六种含不同取代基的探针分子进行了几何构型优化及激发态计算, 探讨了不同取代基对PET效应影响. 计算结果表明: 基态时这些探针分子的最高占有分子轨道(HOMO)和最低未占有分子轨道(LUMO)都在荧光母体BODIPY的π, π^*轨道, 而识别基团上氮原子孤对电子所在的轨道为HOMO-1轨道. 但是在激发态, 当氮原子上有两个取代基时, HOMO-1→LUMO跃迁的激发能都小于荧光团的HOMO→LUMO跃迁, 这将有可能产生PET效应并导致荧光熄灭, 而当氮原子上有一个取代基时不会出现这种现象. 通过激发态结构优化可以发现, 无论识别基团氮原子上有一个还是两个取代基, N原子的轨道对称性都发生变化, 由sp³→sp², 孤对电子占据在p轨道上, 其轨道能级升高至荧光团的HOMO和LUMO轨道之间, 将导致不同程度的PET效应, 与实验结果一致.     

Phenoxazine‐based Near‐infrared Fluorescent Probes for the Specific Detection of Copper (II) Ions in Living Cells

Abstract : It is well known that copper ions play a critical role in various physiological processes. However, a variety of human diseases are tightly correlated with copper overload. Although there are numerous fluorescent probes capable of detecting copper ions, most of them are “turn‐off” probes owing to copper (II) ions fluorescence quenching effect, resulting in poor sensitivity. Herein, a novel “turn‐on” near‐infrared (NIR) fluorescent probe PZ‐N based on phenoxazine was designed and synthesized for the selective detection of copper (II) ions (Cu²⁺). Upon the addition of Cu²⁺, the probe could quickly react with Cu²⁺ and emit strong fluorescence, along with colour change from colourless to obvious blue. Moreover, the probe PZ‐N showed good water solubility, high selectivity, and excellent sensitivity with low limit of detection (1.93 nM) towards copper (II) ions. More importantly, PZ‐N was capable of effectively detecting Cu²⁺ in living cells.     

Sensitive bioanalysis—combining single-molecule spectroscopy with mono-labeled self-quenching probes

Fluorescence single-molecule spectroscopy is an appropriate tool for modern bioanalysis. This technique enables the development of ultra sensitive assays, especially when combined with self-quenching probes. In this review we report novel DNA, enzyme, and antibody assays based on mono-labeled fluorescent probes that are quenched by photoinduced electron transfer (PET).     

Rational Design of Ratiometric Fe3+ Fluorescent Probes Based on FRET Mechanism

As the most abundant transition metal element in mammals, iron(Fe) plays a vital role in life activities. It is of great significance to study the variation of Fe³⁺ level in living organisms. In virtue of the advantages of high sensitivity, good selectivity and low damage to living systems, the fluorescence detection of Fe³⁺ has attracted much attention. Compared with the intensity-based fluorescent probe, the ratiometric fluorescent probe has less interference of environmental and can realize quantitative detection. In this study, four ratiometric Fe³⁺ fluorescent probes, R1, R2, R3 and R4_, were designed and synthesized using fluorescence resonance energy transfer(FRET) mechanism to achieve quantitative detection of Fe³⁺. In the FRET systems, 1,8-naphthalimide fluorophore derivatives were adopted as donors while rhodamine B derivatives were selected as receptors. The connection sites of the donor and acceptor in R3 and R4 are different from those in R1 and R2. All the four probes showed good response and selectivity to Fe³⁺. The energy transfer efficiencies of R3 and R4 were obviously higher than those of R1 and R2. This work provided a promising strategy for the development of fluorescent ratiometic Fe³⁺sensors.     

Molecular engineering of ultra-sensitive fluorescent probe with large Stokes shift for imaging of basal HOCl in tumor cells and tissues

Fluorescent probes have been widely employed in biological imaging and sensing. However, it is always a challenge to design probes with high sensitivity. In this work, based on rhodamine skeleton, we developed a general strategy to construct sensitivity-enhanced fluorescent probe with the help of theoretical calculation for the first time. As a proof of concept, we synthesized a series of HOCl probes. Experiment results showed that with the C-9 of pyronin moiety of rhodamine stabilized by an electron donor group, probe DQF-S exhibited an importantly enhanced sensitivity (LOD: 0.2 nmol/L) towards HOCl together with fast response time (<10 s). Moreover, due to the breaking symmetrical electron distribution by another electron donor group, the novel rhodamine probe DQF-S displayed a far red to near-infrared emission (>650 nm) and large Stokes shift. Bioimaging studies indicated that DQF-S can not only effectively detect basal HOCl in various types of cells, but also be successfully applied to image tumor tissue in vivo. These results demonstrate the potential of our design as a useful strategy to develop excellent fluorescent probes for bioimaging.     

A simple FRET-based modular design for diagnostic probes

In recent years, there has been a massive effort to develop molecular probes with optical modes of action. Probes generally produce detectable signals based on changes in fluorescence properties. Here, we demonstrate the potential of self-immolative molecular adaptors as a platform for Turn-On probes based on the FRET technique. The probe is equipped with identical fluorophore pairs or a fluorophore/quencher FRET pair and a triggering substrate. Upon reaction of the analyte of interest with the triggering substrate, the self-immolative adaptor spontaneously releases the two dye molecules to break off the FRET effect. As a result, a new measurable fluorescent signal is generated. The fluorescence obtained can be used to quantify the analyte. The modular structure of the probe design will allow the preparation of various chemical probes based on the FRET activation technique.     

新型荧光/EPR双功能次氯酸探针的构建及性能

构建了一种新型香豆素-萘酰亚胺荧光/电子顺磁共振双功能探针CNNOH,并结合荧光光谱、电子顺磁共振(EPR)波谱和紫外-可见吸收光谱对其性能进行了研究.结果表明,该探针可结合荧光光谱的灵敏性和EPR波谱的特异性进行次氯酸的检测;由于香豆素与萘酰亚胺之间存在荧光共振能量转移(FRET)效应,探针分子具有较大的Stokes位移(135 nm),可有效避免由激发光导致的杂散光对检测的干扰.该双功能探针具有检出限低(0.214μmol/L)、反应速度快(~10 s)、检测范围宽(0~5 mmol/L)、选择性好及在生理条件下稳定的特点,预期在活体细胞检测方面有良好的应用前景.     

Molecular engineering of ultra-sensitive fluorescent probe with large Stokes shift for imaging of basal HOCl in tumor cells and tissues

Fluorescent probes have been widely employed in biological imaging and sensing. However, it is always a challenge to design probes with high sensitivity. In this work, based on rhodamine skeleton, we developed a general strategy to construct sensitivity-enhanced fluorescent probe with the help of theoretical calculation for the first time. As a proof of concept, we synthesized a series of HOCl probes. Experiment results showed that with the C-9 of pyronin moiety of rhodamine stabilized by an electron donor group, probe DQF-S exhibited an importantly enhanced sensitivity (LOD: 0.2 nmol/L) towards HOCl together with fast response time (<10 s). Moreover, due to the breaking symmetrical electron distribution by another electron donor group, the novel rhodamine probe DQF-S displayed a far red to near-infrared emission (>650 nm) and large Stokes shift. Bioimaging studies indicated that DQF-S can not only effectively detect basal HOCl in various types of cells, but also be successfully applied to image tumor tissue in vivo. These results demonstrate the potential of our design as a useful strategy to develop excellent fluorescent probes for bioimaging.