基于量子点的分子灯塔探针的制备及其在DNA探针中的应用

根据荧光共振能量转移理论合成出一种新颖的分子灯塔探针.由于CdTe量子点（QD s）的荧光发射光谱与DABCYL的紫外-可见吸收光谱有很好的重叠性,所以此种探针采用CdTe量子点作为能量给体,DABCYL作为能量受体.通过水相法合成出直径为2.5 nm的CdTe量子点,并且在偶联剂1-乙基-3-（3-二甲基氨丙基）碳二亚氨盐酸盐（EDC）作用下,与5-′NH2-DNA-DABCYL连接得到了分子灯塔探针.实验发现探针的荧光强度相比CdTe-DNA有明显的下降,最大能量转移效率为68.3%,表明CdTe QD s和DABCYL之间发生了荧光共振能量转移.结果表明,此种探针体系对于互补DNA及其变种有着很好的特异性,且其检测极限为5.170×10^-9mol/L.     

检测金属离子的R-S-F结构型荧光分子传感器研究进展

Receptor-Spacer-Fluorophore(R-S-F)结构型荧光分子传感器是由可选择性结合客体的主体基团与传递信号的荧光团通过桥联基团连接而成的一类分子传感器,结合了超分子在分子识别中良好的选择性和荧光信号的高灵敏度两个优点,成为一类可用于检测金属离子并具巨大发展潜力的新型光学敏感材料.以超分子主体化合物...     

比率型CN-检测荧光探针的合成与应用

利用CN-诱导的迈克尔加成反应阻断探针的分子内电荷转移过程(ICT),成功设计合成一种新型的荧光比率型CN-荧光探针。该探针对CN-具有显著的荧光比率响应,其荧光光谱蓝移128 nm。相对于其他干扰离子,探针对CN-具有较高的选择性和专一性。通过以上实验为监测CN-浓度提供一个简单有效并具有较高灵敏度的分析方法。     

共价有机框架和荧光分子的一体化自组装对神经毒模拟物的超灵敏检测

荧光分子通过非共价键作用载入到多孔矩阵中能够拓展其应用范围.本文报道了利用乳液限域的方法将带有苯并噻二唑和9,9-二己基芴基团的荧光分子1和共价有机框架(Covalent Organic Frameworks, COFs)一体化自组装,使得分子1通过CH-π作用固定在共价有机框架的骨架之上.因此这会极大地抑制荧光分子之间的π-π作用,使其表现出荧光分子单体的光学性质.更有意思的是,共价有机框架和神经毒剂模拟物(DCP)的特殊的作用,使得一体化自组装的复合物能够实现对神经毒剂模拟物高灵敏度的检测(检测限为40 ppb).而且,当前的一体化组装策略能够被拓展用于装载多种不同发射波长的荧光分子来实现白光.我们的结果提供了一种利用荧光探针分子和共价有机框架综合自组装来制备高发光效率多孔材料的新方法.     

稀土掺杂的荧光探针在生物标记领域中的研究进展

稀土掺杂的荧光探针作为一种新型荧光材料,由于其具有优良的化学稳定性、光稳定性以及低毒性,在生物标记领域引起了人们的广泛关注。综述和分析讨论了近年来有关稀土掺杂的荧光探针的传统制备技术、表面改性方法以及磁-光双功能的实现等,同时介绍了荧光探针在多色标记和多模式发光技术中的研究现状和发展趋势。     

荧光探针在食品智能包装中的应用

通过监测食品包装内一些理化指标(O_2、H_2S、CO_2、酸碱度、碳水化合物)判定食品的新鲜程度,是新时代下智能包装领域的一大研究热点及难点。荧光探针法因具有专一性强、灵敏度高、响应速度快、可控性强等特点,被广泛应用于识别某些理化指标,具备判断食品新鲜度的功能。首先对荧光探针的荧光机理进行简介,然后对近十多年来O_2荧光探针、H_2S荧光探针、碳水化合物荧光探针以及其他类型的荧光探针的研究现状进行了归纳总结,最后对荧光探针在食品智能包装中的应用前景进行了展望。     

基于荧光标记的液相芯片检测方法研究

讨论了基于荧光标记的液相芯片及其二维并行检测方法. 设计了待测试液的特殊流场. 利用脉冲激光激发微球探针上的荧光,配合高灵敏度的 CCD 检测荧光信息,计算机对各个 CCD 记录的荧光信息进行后期处理,获得液相芯片中微球探针上的全部信息. 对检测技术方案中探针流态和荧光信号的强度进行了分析,建立了荧光信号强度与检测系统中各参量间的表达式. 每个探测单元都对荧光信号的收集进行了验证实验. 这种检测方法具有快速、准确、灵敏度高的优点.     

分子荧光探针和光量子光纤器件研究

阐述了绿色荧光蛋白的晶体结构和发光特性,以及荧光蛋白在异源细胞内能自发产生荧光,用于活细胞适时定位观察,研究外界信号刺激下蛋白的变化过程,获得自然真实状态。荧光蛋白成像技术使错综复杂的细胞结构和功能研究达到跟踪、定位、监测和动态观察。查明化学反应在细胞、组织间的传递过程。介绍了分子荧光探针的主要优越性及其在生命科学、医学研究和药物开发中的应用。光量子光纤器件是指光动力治疗时光敏物质在光照下由基态激发所吸收的能量量子化,有利于促进细胞再生,提高疗效。将分子荧光探针和光量子治疗光纤器件形成一体化集成系统。将实现重大疾病的早期检测、病灶的精确定位、靶向量子治疗与实时在线跟踪一体化。     

新型化学功能材料——瓜环与荧光化合物的主客体自组装研究进展

瓜环作为第四代超分子主体,两端由羰基氧原子环绕而成,内部为疏水性的空腔,具有刚性结构,微溶于水,不溶于有机溶剂。能与瓜环组成配合物的荧光类客体种类较多,通过荧光光谱的变化可以检测出主-客体相互作用,这一特性拓展了瓜环在生物化学领域的应用,包括医药载体、核酸检测、分子识别、pH探针等方面。未来研究中可以尝试以不同的发色母体取代不同的位点,这将为新型荧光试剂的设计与开发提供重要思路。     

三苯胺类荧光探针的研究进展

三苯胺结构单元中,与氮原子相连的3个苯环具有较高的活性、结构多样性和易裁剪修饰的特性,因此通过在苯环适当的位置外接不同的识别基团,可得到一系列具有特定传感性能的三苯胺类荧光探针分子。系统总结了三苯胺衍生物在金属离子、阴离子和小分子检测中的研究进展,并对探针分子的设计思路、合成方法、应用范围等进行了详细的比较分析,同时对其未来的发展趋势进行了展望。     

Simple and universal platform for logic gate operations based on molecular beacon probes

A new platform technology is herein described with which to construct molecular logic gates by employing the hairpin-structured molecular beacon probe as a basic work unit. In this logic gate operation system, single-stranded DNA is used as the input to induce a conformational change in a molecular beacon probe through a sequence-specific interaction. The fluorescent signal resulting from the opening of the molecular beacon probe is then used as the output readout. Importantly, because the logic gates are based on DNA, thus permitting input/output homogeneity to be preserved, their wiring into multi-level circuits can be achieved by combining separately operated logic gates or by designing the DNA output of one gate as the input to the other. With this novel strategy, a complete set of two-input logic gates is successfully constructed at the molecular level, including OR, AND, XOR, INHIBIT, NOR, NAND, XNOR, and IMPLICATION. The logic gates developed herein can be reversibly operated to perform the set-reset function by applying an additional input or a removal strand. Together, these results introduce a new platform technology for logic gate operation that enables the higher-order circuits required for complex communication between various computational elements.     

A novel fluorescent label based on organic dye-doped silica nanoparticles for HepG liver cancer cell recognition

In this paper, we report a method for the recognition of HepG liver cancer cells with the use of a novel fluorescent label based on organic dye-doped fluorescent silica nanoparticles. The novel organic dye-doped silica nanoparticles are prepared with a water-in-oil microemulsion technique. The silica network is produced by the controlled synchronous hydrolysis of tetraethoxysilane and 3-amino-propyltriethoxysilane (APTES). The organic dye fluorescein isothiocyanate is doped inside as a luminescent signaling element, through covalent bonding to the amino group of APTES. The organic dye-doped core-shell nanoparticles are highly luminescent and exhibit minimal dye leaching and excellent photostability. A novel fluorescent label method based on biological fluorescent nanoparticles has been developed. The dye-doped fluorescent silica nanoparticles are covalently immobilized with anti-human liver cancer monoclonal antibody HAb18. We have used antibody-labeled fluorescent nanoparticles to recognize HepG liver cancer cells. It has been observed that the bioassay based on the organic dye-doped nanoparticles can identify the target cells selectively and efficiently. The fluorescent nanoparticle label also exhibits high photostability.     

Molecular Aptamer Beacons and Their Applications in Sensing,Imaging, and Diagnostics

The ability to monitor types, concentrations, and activities of different biomolecules is essential to obtain information about the molecular processes within cells. Successful monitoring requires a sensitive and selective tool that can respond to these molecular changes. Molecular aptamer beacon (MAB) is a molecular imaging and detection tool that enables visualization of small or large molecules by combining the selectivity and sensitivity of molecular beacon and aptamer technologies. MAB design leverages structure switching and specific recognition to yield an optical on/off switch in the presence of the target. Various donor–quencher pairs such as fluorescent dyes, quantum dots, carbon‐based materials, and metallic nanoparticles have been employed in the design of MABs. In this work, the diverse biomedical applications of MAB technology are focused on. Different conjugation strategies for the energy donor–acceptor pairs are addressed, and the overall sensitivities of each detection system are discussed. The future potential of this technology in the fields of biomedical research and diagnostics is also highlighted.     

Aqueous self-assembly and surface-functionalized nanodots for live cell imaging and labeling

Nanoparticles have enormous potential for bioimaging and biolabeling applications, in which conventional organically based fluorescent labels degrade and fail to provide long-term tracking. Thus, the development of approaches to make fluorescent probes water soluble and label cells efficient is desirable for most biological applications. Here, we report on the fabrication and charac- terization of self-assembled nanodots （SANDs） from 3-aminopropyltriethoxysilane （APTES） as a probe for protein labeling. We show that fluorescent SAND probes exhibit both bright photoluminescence and biocompatibility in an aqueous environment. Selective in vitro imaging using protein and carbohydrate labeling of hepatoma cell lines are demonstrated using biocompatible SANDs conjugated with avidin and galactose, respectively. Cytotoxicity tests show that conjugated SAND particles have negligible effects on cell proliferation. Unlike other synthetic systems that require multistep treatments to achieve robust surface functionalization and to develop flexible bioconjugation strategies, our results demonstrate the versatility of this one-step SAND fabrication method for creating multicolor fluorescent probes with the tailored functionalities, effident emission, as well as excellent biocompatibility, required for broad biological use.     

Molecular Cancer Imaging in the Second Near‐Infrared Window Using a Renal‐Excreted NIR‐II Fluorophore‐Peptide Probe

In vivo molecular imaging of tumors targeting a specific cancer cell marker is a promising strategy for cancer diagnosis and imaging guided surgery and therapy. While targeted imaging often relies on antibody‐modified probes, peptides can afford targeting probes with small sizes, high penetrating ability, and rapid excretion. Recently, in vivo fluorescence imaging in the second near‐infrared window (NIR‐II, 1000–1700 nm) shows promise in reaching sub‐centimeter depth with microscale resolution. Here, a novel peptide (named CP) conjugated NIR‐II fluorescent probe is reported for molecular tumor imaging targeting a tumor stem cell biomarker CD133. The click chemistry derived peptide‐dye (CP‐IRT dye) probe afforded efficient in vivo tumor targeting in mice with a high tumor‐to‐normal tissue signal ratio (T/NT > 8). Importantly, the CP‐IRT probes are rapidly renal excreted (≈87% excretion within 6 h), in stark contrast to accumulation in the liver for typical antibody‐dye probes. Further, with NIR‐II emitting CP‐IRT probes, urethra of mice can be imaged fluorescently for the first time noninvasively through intact tissue. The NIR‐II fluorescent, CD133 targeting imaging probes are potentially useful for human use in the clinic for cancer diagnosis and therapy.     

Regenerable fiber-optic-based immunosensor

An immunosensor is described that is based on fluorescently labeled F(ab') anti-human serum albumin antibody fragments covalently immobilized to the distal end of a fiber-optic probe. When human serum albumin is present, it is bound to the sensor and shields the fluorescent label from the solvent water, and a significant increase in the label fluorescence results. The sensor can be regenerated by simply immersing the sensing tip in chaotropic media. Under these conditions the antigen-antibody complex is selectively disrupted without adversely affecting the sensor. In the present configuration, the same sensor can be recycled over 50 times before the immunosurface inactivates significantly. With proper storage the sensor can last for up to 4 months.     

分子印迹聚合物

简单介绍了分子印迹聚合物(MIP)的制备及其分子识别机理,重点总结了MIP在分离领域的应用.     

M13 Virus‐Based Framework for High Fluorescence Enhancement

Fluorescence imaging is a powerful tool for studying biologically relevant macromolecules, but its applicability is often limited by the fluorescent probe, which must demonstrate both high site‐specificity and emission efficiency. In this regard, M13 virus, a versatile biological scaffold, has previously been used to both assemble fluorophores on its viral capsid with molecular precision and to also target a variety of cells. Although M13‐fluorophore systems are highly selective, these complexes typically suffer from poor molecular detection limits due to low absorption cross‐sections and moderate quantum yields. To overcome these challenges, a coassembly of the M13 virus, cyanine 3 dye, and silver nanoparticles is developed to create a fluorescent tag capable of binding with molecular precision with high emissivity. Enhanced emission of cyanine 3 of up to 24‐fold is achieved by varying nanoparticle size and particle‐fluorophore separation. In addition, it is found that the fluorescence enhancement increases with increasing dye surface density on the viral capsid. Finally, this highly fluorescent probe is applied for in vitro staining of E. coli. These results demonstrate an inexpensive framework for achieving tuned fluorescence enhancements. The methodology developed in this work is potentially amendable to fluorescent detection of a wide range of M13/cell combinations.