非标记型p53抑癌基因电化学DNA生物传感器的研究

基于发夹型核酸探针的高特异性识别能力以及电活性物质与DNA磷酸骨架间的静电作用,以发夹型核酸作为分子识别探针,电活性物质六氨合钌(RuHex)作为杂交指示剂,构建了一种非标记型检测p53抑癌基因的电化学DNA生物传感器.实验结果表明,在10 μmol/L RuHex溶液中,该传感器对目标DNA具有灵敏的电化学响应,电化...     

基于核酸适体的电化学生物传感器*

核酸适体是一类体外筛选的、可与目标分子高效、高特异亲合的RNA或DNA寡核苷酸片段,与常规识别分子（如抗体等）相比,核酸适体作为一类新型识别分子具有明显特色和优势,已被广泛应用于生物传感等分子识别和应用研究领域。本文就基于核酸适体的电化学生物传感器（标记型和非标记型）的近期进展作简要评述,包括适体简介、标记型（“信号衰减”型、“信号增强”型、酶标记型和纳米粒子标记型）和非标记型电化学适体生物传感器等内容。     

基于核酸适体的外泌体分子识别研究进展

自研究者证实外泌体承担了细胞外RNA等物质的运输功能以来, 关于外泌体来源与功能的研究一直备受关注. 近年来外泌体被发现具有作为疾病生物标志物的潜力, 使得拥有特定表面蛋白以及特定装载物的外泌体成为分析化学领域有价值的检测对象. 从化学本质角度来说, 外泌体的获取与分析需要依赖特异性的分子识别过程. 核酸适体作为分子识别单元, 因其特异性强、 亲和力高、 生物活性稳定、 易于合成和保存、 而且其序列和结构上具有可编程性, 易于设计和修饰, 已成功地用在外泌体相关的生物传感体系中. 本文从外泌体的化学组成及其具有生理、 病理意义的组分出发, 从外泌体通用生物标志物识别、癌细胞来源外泌体的检测及外泌体蛋白谱的分析这3个方面综述了以核酸适体作为分子识别单元在外泌体分析领域的代表性工作, 总结了现有的靶向外泌体的核酸适体序列信息以及应用场景, 阐述了利用化学合成与修饰以及DNA自组装等化学调控手段增强核酸适体分子识别性能的最新进展, 并从适用于外泌体分子识别的核酸适体的筛选以及化学修饰的角度, 对未来的研究方向进行了展望.     

功能化核酸适体的筛选及分子识别应用

核酸适体是从寡核苷酸文库中筛选获得的一段单链寡核苷酸. 由于能与多种靶标分子高特异性结合, 核酸适体已发展成为一种新兴的分子识别工具, 广泛应用于生物医学等领域. 天然核酸文库有限的化学组成限制了核酸适体的结构和功能, 进而限制了其在分子识别中的应用. 功能化核酸适体通过引入特定的化学官能团使核酸序列具有更丰富的构象和功能, 增强其分子识别能力. 然而, 功能化核酸很难与核酸扩增方法兼容, 因而难以使用传统筛选方法进行功能化核酸的筛选. 因此, 优化筛选方法对于获得具有优异性能的功能化核酸适体至关重要. 本综述总结了功能化核酸适体的筛选方法, 并介绍了其作为分子识别工具在生物医学领域中的应用.     

适体及其在分析检测中的应用

适体的出现使人们认识到核酸不仅可以作为遗传信息存储和转运的载体,还可以作为一种具有识别功能的分子。适体对目标物的识别具有高选择性和高亲和力,还有很多其它传统识别分子所不具备的优点,这使得其在分析检测领域得到关注和广泛应用。对适体的筛选过程、特点以及其在分析检测方面的主要应用进行综述。     

生物电分析新方法与技术研究及仪器研制

生物电分析化学是一门利用生物分子作为识别元件、通过生物反应后电极过程产生的信号的变化对未知物质进行定性、定量分析的学科.目前常用的生物识别元件有酶、核酸(包括核酸适配体)、抗体、受体等,而可供检测的信号广义上包括电流、电阻、光电流和电化学发光等.在过去5年的工作中,我们针对生命科学、临床检验和环境监测等实际应用领域,分别研究了电化学酶传感器、光电化学核酸损伤传感器和电化学发光免疫检测的原理与技术,并研制了相应的检测仪器.     

光电化学生物分析研究进展

光电化学生物分析是近年来新出现并发展迅速的一种分析技术,其检测原理是基于在光照下识别元件和目标分子之间的生物识别作用造成光电活性物质产生的电信号的改变,以实现对待测物的定量测定。由于其灵敏选择性检测的优点及其在生物分析中的巨大潜力,该方法吸引了较多的关注,并且在检测性能和生物传感应用等方面也取得了较大进步。本文针对光电化学生物分析中常见的四种应用领域,即直接光电化学检测、光电化学酶检测、光电化学核酸检测以及光电化学免疫分析,综述了近年来国内外在光电化学生物分析研究领域的最新进展,并对其未来发展进行了展望。     

核酸适配体传感器在黄曲霉毒素B1检测中应用研究进展北大核心CSCD

核酸适配体作为一种新型识别分子,具有亲和力高、稳定性强、制备成本低、特异性强等优点,但其自身不具有信号转换功能,它与靶标分子特异性结合过程,不可产生被检测的物理化学信号。因此,需将核酸适配体与靶标分子特异性识别结合过程转为易于被检测的物理化学信号变化的过程。根据信号转换方式的不同,可将适配体生物传感器分为荧光适配体传感器、比色适配体传感器、电化学适配体传感器和表面拉曼散射适配体传感器。本文对基于以上4种检测信号的核酸适配体生物传感器在黄曲霉毒素(AFB1)检测方面的应用进行综述,并概述该类传感器应用前景和当前面临的挑战。     

螺吡喃化合物在分析化学中的应用

螺吡喃作为一种有机光致变色化合物,能够发生无色闭环体螺吡喃与有色开环体部花菁之间可逆的结构异构化,由于具有特殊的分子识别能力和信号传导功能,已经成为分子探针领域极具吸引力的主体分子之一。螺吡喃不仅被广泛应用于光电材料领域作为分子器件,而且作为传感器广泛应用于分析化学领域。研究者们设计了多种具有不同结构的螺吡喃分子,将其应用于光化学和电化学传感领域。本文系统综述了螺吡喃化合物在分析化学领域的研究进展,包括螺吡喃作为光学探针在分子识别(对金属离子、阴离子及有机分子的定性及定量分析)方面的应用,以及螺吡喃在电化学免疫传感器中的应用。     

偶氮苯作用的核酸开关在生物体内的可逆光调控

随着人们对偶氮苯分子光异构化机理和特性认识的深入,偶氮苯在核酸分子中的引入及其相关过程的可逆调控也受到了大量关注.偶氮苯分子作为光响应元件不仅用于合成智能材料或分子机器,而且正迅速渗透到化学生物学体系的分析和调控.考虑到核酸分子包含的信息多样性,小分子偶氮化合物引入到核酸分子中,可实现开关核酸的结构、RNA沉默、基因表达、适配体识别、酶活性等,也可用作核酸探针了解结构信息和分子之间的作用机理.因而,功能核酸的光可逆调控及其在生物领域中的应用,成为核酸化学领域的热门课题.本文主要阐述了偶氮苯与核酸结合的4种不同方式的设计原理及特点,通过筛选一些有代表性的例子,介绍偶氮苯类光敏分子的光异构化性能及其对核酸结构和功能的可逆调控在生物领域的研究进展,并列举出现阶段可能存在的问题,及对未来的发展前景进行展望.     

In Vitro Selection of Specific Ligand-binding Nucleic Acids

In vitro selection is a method that allows the simultaneous screening of very large numbers of nucleic acid molecules for a wide range of properties from binding characteristics to catalytic properties; moreover, the isolation of the very rare functional molecules becomes possible. Binding sites between proteins and nucleic acids, for example, have been evaluated by this methodology in order to gain information about protein/nucleic acid interactions. Structure and function of catalytic RNA (“ribozymes”) has been studied by in vitro selection and has led to new ribozymes with improved catalytic function. Substrate specificity of catalytic RNA has been changed and has led to a ribozyme that cleaves DNA. Other applications include the isolation of nucleic acids that bind specifically to small organic molecules and of RNA molecules that form triple helices with double-stranded DNA. In this article we discuss the background, design, and results of in vitro genetic experiments, which bridge biochemical/molecular biological and organic chemical approaches to molecular recognition.     

Nucleic acid based molecular devices

In biology, nucleic acids are carriers of molecular information: DNA's base sequence stores and imparts genetic instructions, while RNA's sequence plays the role of a messenger and a regulator of gene expression. As biopolymers, nucleic acids also have exciting physicochemical properties, which can be rationally influenced by the base sequence in myriad ways. Consequently, in recent years nucleic acids have also become important building blocks for bottom-up nanotechnology: as molecules for the self-assembly of molecular nanostructures and also as a material for building machinelike nanodevices. In this Review we will cover the most important developments in this growing field of nucleic acid nanodevices. We also provide an overview of the biochemical and biophysical background of this field and the major "historical" influences that shaped its development. Particular emphasis is laid on DNA molecular motors, molecular robotics, molecular information processing, and applications of nucleic acid nanodevices in biology.     

Regulation of Protein Activity and Cellular Functions Mediated by Molecularly Evolved Nucleic Acids

Regulation of protein activity is essential for revealing the molecular mechanisms of biological processes. DNA and RNA achieve many uniquely efficient functions, such as genetic expression and regulation. The chemical capability to synthesize artificial nucleotides can expand the chemical space of nucleic acid libraries and further increase the functional diversity of nucleic acids. Herein, a versatile method has been developed for modular expansion of the chemical space of nucleic acid libraries, thus enabling the generation of aptamers able to regulate protein activity. Specifically, an aptamer that targets integrin alpha3 was identified and this aptamer can inhibit cell adhesion and migration. Overall, this chemical‐design‐assisted in vitro selection approach enables the generation of functional nucleic acids for elucidating the molecular basis of biological activities and uncovering a novel basis for the rational design of new protein‐inhibitor pharmaceuticals.     

Aptamers: molecular tools for analytical applications

Aptamers are artificial nucleic acid ligands, specifically generated against certain targets, such as amino acids, drugs, proteins or other molecules. In nature they exist as a nucleic acid based genetic regulatory element called a riboswitch. For generation of artificial ligands, they are isolated from combinatorial libraries of synthetic nucleic acid by exponential enrichment, via an in vitro iterative process of adsorption, recovery and reamplification known as systematic evolution of ligands by exponential enrichment (SELEX). Thanks to their unique characteristics and chemical structure, aptamers offer themselves as ideal candidates for use in analytical devices and techniques. Recent progress in the aptamer selection and incorporation of aptamers into molecular beacon structures will ensure the application of aptamers for functional and quantitative proteomics and high-throughput screening for drug discovery, as well as in various analytical applications. The properties of aptamers as well as recent developments in improved, time-efficient methods for their selection and stabilization are outlined. The use of these powerful molecular tools for analysis and the advantages they offer over existing affinity biocomponents are discussed. Finally the evolving use of aptamers in specific analytical applications such as chromatography, ELISA-type assays, biosensors and affinity PCR as well as current avenues of research and future perspectives conclude this review.     

Advances in nucleic acid architectures for electrochemical sensing

Nucleic acid–based electrochemical sensors are ideally suited to the detection of molecular targets for which enzymatic detection or direct electrochemical oxidation – reduction reactions are not possible. Moreover, the versatility of nucleic acids in their ability to bind a great variety of target types, from small molecules to single-entity mesoscopic targets, makes them attractive receptors for the development of electrochemical biosensors. In this brief opinion piece, we discuss field advances from the past two years. We hope the works highlighted here will inspire the community to pursue creative designs enabling the detection of larger and more complex targets with a specific focus on analytical validation and translation into preclinical or clinical applications.     

Electrochemical nanomaterial-based nucleic acid aptasensors

Recent progress in the development of electrochemical nanomaterial–aptamer-based biosensors is summarized. Aptamers are nucleic acid ligands that can be generated against amino acids, drugs, proteins, and other molecules. They are isolated from a large random library of synthetic nucleic acids by an iterative process of binding, separation, and amplification, called systematic evolution of ligands by exponential enrichment (SELEX). In this review, different methods of integrating aptamers with different nanomaterials and nanoparticles for electrochemical biosensing application are described.     

Solid composite electrodes for DNA enrichment and detection

New plastic composite electrodes with appliance in medical diagnostic are described. The new electrode material offers the possibility of specific electrical enrichment and electrochemical analysis of nucleic acid sequences. To facilitate selective enrichment of target nucleic acids, specific probe oligonucleotides were attached covalently to free carboxyl groups of conducting polycarbonate/carbon fiber electrodes. Complementary oligonucleotides were enriched from analyte solutions by electric field supported methods. The analysis of the PCR product shows the efficiency and selectivity of the electrical enrichment. We have also shown that inexpensive and robust solid electrodes made of polycarbonate and conductive carbon powder are suitable for electrochemical examination of nucleic acids. The combination of electrochemical enrichment of DNA and subsequent electrochemical detection is a promising approach towards an inexpensive molecular diagnosis kit.     

Programming Non-Nucleic Acid Molecules into Computational Nucleic Acid Systems

Nucleic acid (NA) computation has been widely developed in the past years to solve kinds of logic and mathematic issues in both information technologies and biomedical analysis. However, the difficulty to integrate non-NA molecules limits its power as a universal platform for molecular computation. Here, we report a versatile prototype of hybridized computation integrated with both nucleic acids and non-NA molecules. Employing the conformationally controlled ligand converters, we demonstrate that non-NA molecules, including both small molecules and proteins, can be computed as nucleic acid strands to construct the circuitry with increased complexity and scalability, and can be even programmed to solve arithmetical calculations within the computational nucleic acid system. This study opens a new door for molecular computation in which all-NA circuits can be expanded with integration of various ligands, and meanwhile, ligands can be precisely programmed by the nuclei acid computation.