基于DNA纳米结构的细胞间相互作用的调控

细胞通过化学信号、 电子交换和直接接触等方式交换彼此之间的物质和信息, 以调节生命体的生长发育. 因此, 细胞间的相互作用研究与调控在细胞功能的机制研究和疾病的诊断及治疗等领域具有非常重要的意义. DNA纳米结构具有易合成、 易修饰、 可编程性设计及生物安全性高等优点, 有望实现操作简单、 精确可调、 智能响应的细胞间相互作用调控, 受到了广泛关注. 本文综述了寡核苷酸链杂交、 受体-配体结合和核酸适体靶向识别等基于DNA纳米结构的细胞组装策略, 总结了pH调控、 金属离子调控和DNA链激活等细胞间相互作用的调控手段, 并重点介绍了其在细胞间作用力的测量和成像、 体外组织模型的构建、 细胞间的通讯交流和细胞免疫治疗等领域的应用. 最后对该领域进行了总结和展望, 希望为相关研究提供有益参考.     

核酸适体偶联药物的生物偶联构建技术与应用

核酸适体被称为“化学抗体”, 具有与抗体类似或更加优异的特异性和亲和力, 可以精准地靶向靶蛋白, 与靶蛋白特异性结合. 此外, 核酸适体还具有获取简单、 合成简便、 易于进行化学修饰、 不易变性、 靶标范围广、 免疫原性低及细胞内化快等优点, 已被广泛应用于众多研究领域. 在癌症治疗领域, 核酸适体作为一种优异的靶向识别工具和药物递送载体, 可实现抗肿瘤药物的精准递送. 将核酸适体与药物分子偶联, 可通过核酸适体的靶向作用使药物分子随核酸适体共同进入靶细胞, 实现药物分子在靶细胞内的富集, 进而促进靶细胞的死亡. 近年来, 核酸适体偶联药物已成为癌症靶向治疗的前沿新兴领域, 希望通过该领域的深入研究为癌症靶向治疗领域提供新思路. 本文综合评述了以生物偶联技术构建的核酸适体偶联药物及其应用研究.     

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.     

程序自组装DNA纳米花封装酶分子用于光热法检测循环肿瘤细胞

DNA纳米技术在生物传感领域引起人们广泛的研究兴趣,现已构建多种二维和三维DNA功能纳米结构.滚环扩增(RCA)作为一种等温扩增技术,为DNA纳米材料的设计和自组装提供了新途径.该文通过RCA一锅法合成封装有辣根过氧化物酶(HRP)的DNA纳米花(HRP@DNFs),进一步基于双核酸适体识别构建光热生物传感器,用于肝细...     

化学修饰提高核酸适体结合亲和力的研究进展

核酸适体(Aptamer)是通过体外筛选得到的短单链DNA或RNA寡核苷酸, 具有与抗体相当或更优异的特异性及亲和力, 且具有靶标范围广、 易制备和灵活可控修饰、 免疫原性低、 批次差异性小以及易于运输保存等优势, 为食品、 环境和生物医学等领域提供了全新的分子识别工具, 获得了研究者的广泛关注. 但是目前其商业应用的数量仍有限. 为了增强核酸适体的应用性能, 研究者对核酸适体进行了大量的改性研究. 本文系统总结了核酸适体筛选前、 后采用非共价或共价方式对其进行化学修饰, 以增加核酸适体与靶标的结合亲和力的相关研究进展, 并对未来发展前景进行了展望.     

核酸适体-纳米材料复合物用于癌症的诊断与靶向治疗研究进展

因具有独特的光、电、磁、热等优异性能,纳米材料已被广泛应用于生物分析与生物医学领域。核酸适体是一类能够高亲和力和高特异性地与靶标结合的寡核苷酸序列。将核酸适体作为识别单元与纳米材料相结合,可以构建核酸适体-纳米材料复合物。近年来,在肿瘤靶向治疗方面,核酸适体-纳米材料复合物受到了人们的广泛关注。通过纳米材料与具有特异性识别能力的核酸适体的结合,核酸适体-纳米材料复合物可以为癌症治疗提供一种更有效的、低毒副作用的新策略。本文综述了核酸适体-纳米材料复合物作为药物输送载体在癌症的特异性识别与诊断及靶向治疗方面的应用。除此之外,本文还总结了核酸适体-纳米材料复合物与其他新兴技术的有效结合从而提高选择性和癌症治疗效率的相关研究进展。     

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.     

适体功能化的金纳米棒用于癌症靶向治疗的研究进展

金纳米棒(gold nanorods,GNRs)具有特殊的光学性质、较大的比表面积、出色的光热转换性能、表面易修饰等特点,在药物递送、光疗、生物成像和化学传感等领域应用十分广泛。适体是短的单链DNA或RNA片段,可特异性识别癌细胞或其表面的膜蛋白。近年来,适体功能化的GNRs在癌症靶向治疗领域显示出良好的应用前景。根据GNRs对癌症作用机制的差异,本文从光热疗法、光动力疗法、化疗和联合疗法4个方面总结了适体功能化的GNRs在癌症靶向治疗中的最新进展,并对该领域面临的主要挑战和发展趋势进行了探讨与展望。     

核酸适体在生物医学中的应用*

核酸适体是经配体指数富集系统进化技术（SELEX）筛选获得的一类能够特异性地结合离子、分子,甚至整个细胞的单链DNA或者RNA分子。本文介绍了核酸适体及相关筛选技术SELEX;综述了近年来以提高筛选效率和效果为目标的核酸适体筛选技术新进展;列举了核酸适体在无机离子、小分子、生物大分子和肿瘤细胞检测、肿瘤标记物的发现等方面的应用;讨论了基于核酸适体的靶向治疗策略;最后对核酸适体在生物医学上的应用前景进行了展望。     

基于功能核酸的细胞荧光成像

细胞是生物体基本的结构和功能单元,对活细胞中特定生物组分进行动态分析,将为相关生命活动过程的研究提供重要信息。荧光成像为细胞分析提供了一种操作简单、灵敏度高、可实时监测细胞微观动态分子过程的光学生物成像技术。发展高性能的荧光探针用于活细胞成像已成为研究热点。功能核酸是一类具有特殊化学和生物学功能的寡核苷酸分子,除了天然存在的核酶(Ribozyme)和核糖开关(Riboswitch)之外,还包括通过指数富集的配体系统进化技术(SELEX)筛选获得的核酸适体和脱氧核酶(DNAzyme)。功能核酸由于具有合成简单、免疫原性低、相对分子质量小、化学稳定性高、易于修饰等优点,在生物成像领域受到广泛关注。本文主要综述了基于功能核酸的荧光探针在细胞成像领域中的应用研究,总结了该领域面临的挑战,并对其未来发展方向进行了展望。     

An Aptamer-Nanotrain Assembled from Six-Letter DNA Delivers Doxorubicin Selectively to Liver Cancer Cells

Expanding the number of nucleotides in DNA increases the information density of functional DNA molecules, creating nanoassemblies that cannot be invaded by natural DNA/RNA in complex biological systems. Here, we show how six-letter GACTZP DNA contributes this property in two parts of a nanoassembly: 1) in an aptamer evolved from a six-letter DNA library to selectively bind liver cancer cells; and 2) in a six-letter self-assembling GACTZP nanotrain that carries the drug doxorubicin. The aptamer-nanotrain assembly, charged with doxorubicin, selectively kills liver cancer cells in culture, as the selectivity of the aptamer binding directs doxorubicin into the aptamer-targeted cells. The assembly does not kill untransformed cells that the aptamer does not bind. This architecture, built with an expanded genetic alphabet, is reminiscent of antibodies conjugated to drugs, which presumably act by this mechanism as well, but with the antibody replaced by an aptamer.     

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.     

Recent Advances in DNA-Based Cell Surface Engineering for Biological Applications

Due to its excellent programmability and biocompatibility, DNA molecule has unique advantages in cell surface engineering. Recent progresses provide a reliable and feasible way to engineer cell surfaces with diverse DNA molecules and DNA nanostructures. The abundant form of DNA nanostructures has greatly expanded the toolbox of DNA-based cell surface engineering and gave rise to a variety of novel and fascinating applications. In this review, we summarize recent advances in DNA-based cell surface engineering and its biological applications. We first introduce some widely used methods of immobilizing DNA molecules on cell surfaces and their application features. Then we discuss the approaches of employing DNA nanostructures and dynamic DNA nanotechnology as elements for creating functional cell surfaces. Finally, we review the extensive biological applications of DNA-based cell surface engineering and discuss the challenges and prospects of DNA-based cell surface engineering.     

Rapid detection of a cocaine-binding aptamer using biological nanopores on a chip

This paper describes a methodology for the rapid and highly selective detection of cocaine using a membrane protein channel combined with a DNA aptamer. The DNA aptamer recognizes the cocaine molecule with high selectivity. We successfully detected a low concentration of cocaine (300 ng/mL, the drug test cutoff limit) within 60 s using a biological nanopore embedded in a microchip.     

Current Advances in Aptamer-based Biomolecular Recognition and Biological Process Regulation

The interaction between biomolecules with their target ligands plays a great role in regulating biological functions. Aptamers are short oligonucleotide sequences that can specifically recognize target biomolecules via structural complementarity and thus regulate related biological functions. In the past ten years, aptamers have made great progress in target biomolecule recognition, becoming a powerful tool to regulate biological functions. At present, there are many reviews on aptamers applied in biomolecular recognition, but few reviews pay attention to aptamer-based regulation of biological functions. Here, we summarize the approaches to enhancing aptamer affinity and the advancements of aptamers in regulating enzymatic activity, cellular immunity and cellular behaviors. Furthermore, this review discusses the challenges and future perspectives of aptamers in target recognition and biological functions regulation, aiming to provide some promising ideas for future regulation of biomolecular functions in a complex biological environment.     

Cell-specific internalization study of an aptamer from whole cell selection

Nucleic acid aptamers have been shown many unique applications as excellent probes in molecular recognition. However, few examples are reported which show that aptamers can be internalized inside living cells for aptamer functional studies and for targeted intracellular delivery. This is mainly due to the limited number of aptamers available for cell-specific recognition, and the lack of research on their extra- and intracellular functions. One of the major difficulties in aptamers' in vivo application is that most of aptamers, unlike small molecules, cannot be directly taken up by cells without external assistance. In this work, we have studied a newly developed and cell-specific DNA aptamer, sgc8. This aptamer has been selected through a novel cell selection process (cell-SELEX), in which whole intact cells are used as targets while another related cell line is used as a negative control. The cell-SELEX enables generation of multiple aptamers for molecular recognition of the target cells and has significant advantages in discovering cell surface binding molecules for the selected aptamers. We have studied the cellular internalization of one of the selected aptamers. Our results show that sgc8 is internalized efficiently and specifically to the lymphoblastic leukemia cells. The internalized sgc8 aptamers are located inside the endosome. Comparison studies are done with the antibody for the binding protein of sgc8, PTK7 (Human protein tyrosine kinase-7) on cell surface. We also studied the internalization kinetics of both the aptamer and the antibody for the same protein on the living cell surface. We have further evaluated the effects of sgc8 on cell viability, and no cytotoxicity is observed. This study indicates that sgc8 is a promising agent for cell-type specific intracellular delivery.     

Progress in DNA Aptamers as Recognition Components for Protein Functional Regulation

Proteins play a central role in all domains of life, and precise regulation of their activity is essential for understanding the related biological processes and therapeutic functions. Nucleic acid aptamers, the molecular recognition components derived from systematic evolution of ligands by exponential enrichment(SELEX), can specifically identify proteins with antibody-like recognition characteristics and help to regulate their activity. This minireview covers the SELEX-based selection of protein-binding aptamers, membrane protein analytical techniques based on aptamer-mediated target recognition, aptamer-mediated functional regulation of proteins, including membrane receptors and non-membrane proteins(thrombin as a model), as well as the potential challenges and prospects regarding aptamer-mediated protein manipulation, aiming to supply some useful information for researchers in this field.     

核酸适配体生物传感器在三聚氰胺检测中的应用进展

三聚氰胺常被非法添加到食品中,以提高食品中蛋白质的含量。但是,三聚氰胺一旦进入体内,会对人们的健康造成伤害。因此,对三聚氰胺的检测十分必要。为了弥补传统仪器检测法和免疫检测法的不足,基于核酸适配体开发了一系列新的生物传感器,用于三聚氰胺的检测。按照与三聚氰胺的不同识别机制,把这些新的生物传感器分成了四类,分别为基于多聚胸腺嘧啶DNA链和三聚氰胺识别的生物传感器、基于无嘌呤位点的三链DNA结构和三聚氰胺识别的生物传感器、基于核酸适配体和三聚氰胺识别的生物传感器、基于三聚氰胺和汞离子/铜离子等配位识别的生物传感器。本文按照上述四类方法逐个展开,对核酸适配体生物传感器在三聚氰胺检测中的应用进行了综述,并对它们的优缺点进行阐述。     

DNA Nanotechnology on Live Cell Membranes

Recent developments in DNA nanotechnology have brought various nanoscale structures,devices and functional systems for different applications.As biological barriers with significant functions,cell membranes proide direct interfaces for studying cellular environment and states.So far,DNA nanotechnology engineered on live cell membranes has advanced our fundamental understandings of DNA nanomaterials and facilitated the designs of novel sensing,imaging and therapeutic platforms.In this review,we highlighted strategies and outcomes of using DNA nanotechnology on cell membranes towards various biomedical applications,including biosensing,imaging,cellular function regulations and targeted cancer therapy.Furthermore,we also discussed the challenges and opportunities of DNA nanotechnology on cell membranes towards broader applications.     

结构DNA纳米技术应用新进展

DNA具有非凡的分子识别性能和显著的结构特征,这使得它在材料的纳米级调控方面具有独特的优越性,在许多领域也展现出广阔的应用前景。本文从模块化DNA自组装和DNA折纸术两个方面综述了近些年DNA纳米技术,包括近年来DNA纳米技术中比较新型的组装方法;并从DNA纳米结构作为模板定位纳米粒子和蛋白以及用于生物医药等方面介绍了DNA纳米技术的应用;同时,对DNA纳米技术发展及应用进行了展望。