Advanced Pt hollow nanospheres/rubrene nanoleaves coupled with M-shaped DNA walker for ultrasensitive electrochemiluminescence bioassay

Herein,an intense electrochemiluminescence(ECL)was achieved based on Pt hollow nanospheres/rubrene nanoleaves(Pt HNSs/Rub NLs)without the addition of any coreactant,which was employed for ultrasensitive detection of carcinoembryonic antigen(CEA)coupled with an M-shaped DNA walker(M-DNA walker)as signal switch.Specifically,in comparison with platinum nanoparticles(Pt NPs),Pt HNSs revealed excellent catalytic performance and pore confinement-enhanced ECL,which could significantly amplify ECL intensity of Rub NLs/dissolved O_(2)(DO)binary system.Then,the tracks and M-DNA walker were confined on the Pt HNSs simultaneously to promote the reaction efficiency,whose M-structure boosted the interaction sites between walking strands and tracks and reduced the rigidity of their recognition.Once the CEA approached the sensing interface,the M-DNA walker was activated based on highly specific aptamer recognition to recover ECL intensity with the assistance of exonucleaseⅢ(ExoⅢ).As proof of concept,the“on-off-on”switch aptasensor was constructed for CEA detection with a low detection limit of 0.20 fg/m L.The principle of the constructed ECL aptasensor also enables a universal platform for sensitive detection of other tumor markers.

Dual-miRNA-Propelled Three-Dimensional DNA Walker for Highly Specific and Rapid Discrimination of Breast Cancer Cell Subtypes in Clinical Tissue Samples

Accurate discrimination of cell subtypes at the molecular level is especially important for cancer diagnosis,but no current method allows rapid and precise detection of breast cancer subtypes.Herein,we developed an elegant DNA walker for direct and rapid differentiation of breast cancer cell subtypes via detection of dual-miRNAs in clinical tissue samples.This DNA nanomachine can be specifically initiated by endogenous miR-21 and miR-31,and the sensitivity was dramatically improved due to the DNAzyme-mediated signal amplification.This DNA walker enabled rapid detection of double miRNA characteristics in different breast cell lines and also distinguished the fluctuations in a single cell.Applications of this DNAzyme-based nanomachine in vivo and in clinical samples were demonstrated for efficient detection of breast cancer subtypes,making the method generally applicable for precise management of cancers.

基于DNA步行器的传感器技术在食品安全检测中的研究进展

随着DNA纳米技术的快速发展,各种结构和功能的DNA分子被用于构建具有动态行为的可编程纳米机器。其中,DNA步行器因其能够借助驱动力在预定轨道上自主、逐步移动以产生级联信号放大的优势,成为了生物传感、生物成像以及药物递送等领域日益增长的研究热点,在食品污染物快速超灵敏检测方面展现出巨大的应用潜力。本综述首先简要介绍了DNA步行器的基本原理,并着重阐述了提升DNA步行器行走效率的策略,然后总结了其在食品安全检测中的应用,最后对DNA步行器未来研究方向进行了展望,为推动其实际应用提供了理论指导。

Engineering Multipedal DNA Walker on Paper for Sensitive Electrochemical Detection of Plant MicroRNA

MicroRNAs (miRNAs) are vital regulators in both plants and animals. Therefore, it is highly desirable to develop portable and user-friendly biosensors for convenient and sensitive detection of miRNAs. Herein, a novel paper-based electrochemical biosensor was intelligently engineered for the detection of plant miRNA based on a smart DNA walking machine and λ-exonuclease (λ-Exo)-assisted target recycling amplification. Using TaMIR5086 as a target plant miRNA, the presence of TaMIR5086 could initiate the target recycling process and activate the DNA walker to move along the track on the paper. Then, numerous electroactive molecules-labeled single-strand DNA (ssDNA) would be released and adsorbed onto the surface of screen-printed electrode, generating a remarkably increased electrochemical signal. Benefitting from the dual amplification, the developed biosensor exhibits excellent analytical performance toward TaMIR5086 with a detection limit down to 0.37 pmol/L. Furthermore, the paper-based biosensor could be applied for the analysis of target miRNA in complex biological samples, which found great potential in the fields of miRNA analysis and plant biology research.

pH-Responsive Magnetic I-Motif Container Coupled with DNA Walker for Construction of Dual-Signal Electrochemical Biosensor

Herein,a dual-signal electrochemical biosensor has been developed by self-assembly of pH-activatable i-motif probes on magnetic microparticles(MMPs)coupled with DNA walker for signal amplification.In this study,the cytosine(C)-rich single-stranded DNAs are hybridized with DNA initiators to obtain the long-nicked duplexes with repeated units,which are further captured on MMPs to form the magnetic i-motif containers.The resulting duplexes contain abundant G-C base pairs,thus providing extensive binding sites for doxorubicin(DOX).At acidic pH,the C-rich sequences are folded into i-motif structure,resulting in the release of DOX and walker initiators.In this case,the liberated DOX is adsorbed on gra-phene quantum dots-modified glassy carbon electrode viaπ-πinteraction,while the walker initiators as a moving part can catalyze the hybridization between MB-modified fueler DNA and tracker DNA on electrode,contributing to the generation of dual electrochemical signals induced by MB and DOX.Importantly,the magnetic separation can effectively reduce the background,achieving sensitive biosensing of pH ranging from 4.0 to 7.4 with excellent stability.Moreover,the proposed dual-signal electrochemical biosensor has been successfully applied for accurate monitoring of pH in human serum,which holds great potential in pH-dependent bioassays,especially in ultra-micro analysis for clinical applications.

Autonomous DNA walker： probing cell membrane dynamics

We are all familiar with DNA as the substance that encodes the genomes of all living things.In addition to genetic function,DNA is one of the smartest building blocks for innovative nanostructures.DNA walker is a kind of self-assembled molecular machine that mimics the movement of protein motors in living systems.Usually,DNA walker consists of three parts:a single stranded DNA track,several anchorage sites and a walker strand.The walker strand can move from

基于DNA步行器的适配体传感器快速检测新冠病毒

为开发一种基于DNA步行器的适配体传感器以快速检测新冠病毒RBD。首先制备DNA walker与适配体的复合链,当新冠病毒RBD存在时,竞争性结合适配体,释放DNA walker。通过电还原和共价键和作用制得发夹探针修饰电极,利用DNAzyme驱动的DNA walker在电极表面持续行走,从而不断剪切电极信号探针,增强响应信号,实现新冠病毒蛋白快速检测。检测限(LOD)为3.3 pg/mL(S/N=3),线性范围为0.01~70 ng/mL。该适配体传感器具有优异的稳定性(RSD=4.51%)、重现性(RSD=2.87%)和选择性。在人唾液样本中检测SARS-CoV-2 RBD时回收率为104.51%~107.67%,RSD为4.39%~5.26%。

简单0-1规划问题的动态DNA折纸计算模型

DNA折纸是一种全新的DNA自组装方法。将一个由DNA折纸卡槽、双态DNA机器、DNA行走机器人组装而成的动态折纸应用于求解0-1规划问题。其中DNA折纸卡槽由1条M13脚手架链和202条钉书钉链折叠而成。双态DNA机器分为不修饰和修饰金纳米颗粒两种情况,对应于0-1规划问题约束变量的取值为0或者1。DNA折纸卡槽和DNA双态机器组装成折纸基底。DNA行走机器人是7条单链折叠成的带有粘性末端的DNA折纸。在链的驱动下,DNA行走机器人在折纸基底上顺时针旋转行走,每步旋转120°。DNA行走机器人每走两步,与折纸基底上的DNA双态机器进行链置换,接收修饰的金纳米颗粒。当整个动态行走过程结束,根据透射电镜下DNA行走机器人接收的金纳米颗粒的大小和个数来判断约束变量的取值是否为可行解。该计算模型采用模块化结构,DNA折纸卡槽、双态DNA机器、DNA行走机器人等折纸均单独设计,且采用透射电镜读解,因而提高了模型实现的可行性。

DNA步行器的构建及其在生物分析中的应用

随着DNA纳米技术的不断发展,利用DNA分子构建具有不同结构和功能的纳米机器越来越受到研究人员的关注。DNA步行器作为一种新型的人工纳米机器,它是对自然产生的分子步行器的人工模拟。由于其具有自主定向运动和整合信号的优势,是目前性能优良且应用较广的DNA纳米机器之一。该综述介绍了DNA步行器的组成及其在生物传感分析的应用。

DNA纳米机器及其核酸传感应用

DNA纳米机器是由系列功能核酸序列组成的一类分子机器,由剪切作用和链置换反应驱动,可以在纳米轨道上实现物质的运输。DNA纳米机器易于构建与表征,其结构可以根据需要自由设计且变化可控,因而受到科研工作者的广泛关注。文章概述了DNA纳米机器近几十年来的发展与应用,重点探讨了DNA walker、DNA tweezer、DNA motor三种纳米机器以及它们在核酸传感器中的应用。

DNA步行器的构建及其在生命分析的应用

DNA具有独特的序列依赖性和可编辑性,依赖于此,大量的DNA纳米器件被开发应用,如镊子、齿轮、起重机。在这些器件中,DNA步行器能够依靠链置换、酶剪切、光诱导等行走动力沿着特定的一维、二维、三维的轨道运动,展现出独特的方向性、动态性,被广泛应用于生命分析化学领域。鉴于DNA步行器广阔的应用前景,该综述从步行器的构造、设计原则、行走动力,和其在生命分析应用的角度出发,详细进行了阐述。

基于DNA步行者求解最小顶点覆盖问题的计算模型

DNA步行者作为一类可执行复杂操作的新兴动态DNA纳米机器,可以在纳米尺度上以可控的方式在指定轨道内行走.文章将DNA步行者用于解决最小顶点覆盖问题,首先构造出全部顶点覆盖,用删除实验得到顶点覆盖的补集,再通过荧光探针N-甲基卟啉二丙酸(NMM)特异性识别G-四链体结构,产生荧光,最终得到最小顶点覆盖.该模型设计独特新颖,通用性好,操作简单,运行效率更高.

异或门的DNA步行者计算模型

分子的逻辑计算是建立DNA计算机的基础。为了实现分子逻辑门的计算,在DNA折纸基底上建立了一个动态的异或门(XOR)计算模型,其中DNA折纸基底由1条M13脚手架链和202条订书钉链折叠而成。异或门模型由两条路径组成,每条路径分为左右两个方向,两个方向的中央共同绑定一颗金纳米颗粒。该模型在溶液中稳定存在。不同的输入值对应不同的输入链,输入链驱动对应路径方向上的DNA步行者的移动,到达特定位置置换出路径方向的金纳米颗粒。当两颗金纳米颗粒均与折纸基底分离时,显示异或门结果为假;当两颗金纳米颗粒与折纸基底均未分离时,显示异或门结果为真。

Toeless and reversible DNA strand displacement based on Hoogsteen-bond triplex

Strand displacement reaction is a crucial component in the assembly of diverse DNA-based nanodevices,with the toehold-mediated strand displacement reaction representing the prevailing strategy.However,the single-stranded Watson-Crick sticky region that serves as the trigger for strand displacement can also cause leakage reactions by introducing crosstalk in complex DNA circuits.Here,we proposed the toeless and reversible DNA strand displacement reaction based on the Hoogsteen-bond triplex,which is compatible with most of the existing DNA circuits.We demonstrated that our proposed reaction can occur at pH 5 and can be reversed at pH 9.We also observed an approximately linear relationship between the degree of reaction and pH within the range of pH 5-6,providing the potential for precise regulation of the reaction.Meanwhile,by altering the sequence orientation,we have demonstrated that our proposed reaction can be initiated or regulated through the same toeless mechanism without the requirement for protonation in low pH conditions.Based on the proposed reaction principle,we further constructed a variety of DNA nanodevices,including two types of DNA logic gates that rely on pH 5/pH 9 changes for initiating and reversing:the AND gate and the OR gate.We also successfully constructed a DNA Walker based on our proposed reaction modes,which can move along a given track after the introduction of a programmable DNA sequence and complete a cycle after 4 steps.Our findings suggest that this innovative approach will have broad utility in the development of DNA circuits,molecular sensors,and other complex biological systems.

DNA步行者在检测传感中的应用

DNA步行者(DNA Walker)是一种基于化学能布朗运动的人工模拟机器,由构象迁移和链置换反应驱动,在纳米轨道上实现物质的检测运输。基于DNA Walker的生物传感器是一种集生物和纳米技术于一体的新型高效传感器,在食品安全检测、生物传感等领域有巨大的应用潜力。本文介绍了DNA Walker的发展现状,并通过讨论,系统概述了DNA Walker传感器的设计原理及其在检测传感中的应用。总结了DNA Walker传感器的性能优势和所面临的挑战,并对该技术的研究前景进行了展望。

利用物种特异性PCR技术快速鉴定南瓜实蝇

【目的】快速鉴定我国进境植物检疫性害虫南瓜实蝇Bactrocera tau(Walker),防止该虫传入扩散。【方法】基于物种特异性PCR(SS-PCR)技术,选取20种形态近似的常见实蝇,将南瓜实蝇作为阳性对照,提取基因组DNA模板,选用mt DNA COⅠ序列,检查同源系列,设计筛选1对可快速准确鉴定南瓜实蝇的种特异性引物NF404和NR610,并进行PCR检测和验证,建立一种利用种特异性引物的快速鉴定方法。【结果】南瓜实蝇在207 bp的位置扩增出一条清晰且单一的目标条带,其余果实蝇未见条带。将截获的南瓜实蝇与其同亚属的近缘种具条实蝇、瓜实蝇的不同虫态和成虫部分虫体组织的虫样,采用本实验室建立的SS-PCR鉴定方法进行验证,结果一致。【结论】建立的南瓜实蝇的SS-PCR鉴定方法种特异性和稳定性强,能快速鉴定目标种类,解决口岸进境果蔬中截获实蝇幼虫、蛹等不同虫态和残体难于快速鉴定问题。

5′-碘靛玉红的抗肿瘤作用

5′-碘靛玉红是靛玉红苯环5′位碘取代的衍生物。对大、小鼠急性毒性试验表明,未见与靛玉红有明显差异。对大鼠W256的实验治疗表明,二药等克分子剂量(2mM/kg)或等剂量(800mg/kg)灌胃,本品的抑瘤率为57～72％(P<0.01),靛玉红为30～34％(P<0.05),二者有显著差异。本品的ID_(50)为490±32.9mg/kg,CI大于10;而靛玉红的抑瘤率低于50％。本品还能明显延长L7212小鼠的存活时间41～73％(P<0.01);而靛玉红无活性。P388瘤细胞体外试验表明,二药均能抑制~3H-TdR参入瘤细胞的DNA,但本品的IC_(50)明显低于靛玉红,分别为6.4和17.0μg/ml。以上结果证明了,5′-碘靛玉红的抗癌活性比靛玉红高。

pH-controlled DNAzymes： Rational design and their applications in DNA-machinery devices

The availability and reliability of strategies for molecular biosensing over a finely adjustable dynamic range is essential to enhance the understanding and control of vital biological process. To expand the versatility and utility of nucleic acid- related enzymes, we demonstrated a rational approach to acquiring tunable, pH-dependent deoxyribozymes （DNAzymes） with catalytic activities and response sensitivities that can be tuned through a simple change in solution pH. To do this, we capitalized upon the pH dependence of Hoogsteen interactions and designed i-motif- and triplex-based DNAzymes that can be finely regulated with high precision over a physiologically relevant pH interval. The modified DNAzymes are dependent upon pH for efficient cleavage of substrates, and their catalytic performance can be tuned by regulating the sequence of inserted i-motif/triplex structures. The principle of tunable, pH-dependent DNAzymes provides the opportunity to engineer pH-controlled DNA-machinery devices with unprecedented sensitivity to pH changes. For example, we constructed a DNA-walker device, the stepping rate of which could be adjusted by simply modulating solution pH within an interval of 5.6 to 7.4, as well as a DNA tetrahedron that can be opened at pH 6.4 and kept closed at pH 7.4. The potential of this approach is not limited to serve as pH-dependent devices, but rather may be combined with other elements to expand their practical usefulness.

DNA步行者分子机器研究新进展

作为人类向大自然学习过程中迈出的重要一步,人工分子机器的研究越来越受到人们的重视.由于具有碱基配对的精确性、序列的可编程性、二级结构的多样性和可控性等一系列优势, DNA被认为是最有前途的一类分子机器构筑材料之一.本综述依据驱动力的不同,对一类重要的分子机器——DNA步行者分子机器的最新研究进展进行了介绍,并对该类分子机器的未来发展进行了展望.

基于封闭链释放型磁性DNA分子机器的化学发光传感体系

以核酸外切酶Ⅲ(EXOⅢ)作为驱动力,构建了一种卸载封闭链激活DNAzyme的磁性DNA分子机器,用于化学发光传感分析。将含有富G序列的DNA固定在磁性微球上,并用封闭链封闭富G片段,当有目标DNA存在时,在EXOⅢ的作用下,目标DNA可以循环地将封闭链从磁性微球上卸载,使磁性微球表面生成G-四链体DNAzyme,催化产生化学发光,定量检测目标DNA。该DNA分子机器仅需30 min便可完成循环过程。通过紫外吸收、分子荧光、化学发光、聚丙烯酰胺凝胶电泳等方法验证了DNA分子机器的工作原理。最佳条件下,该分子机器检测DNA的线性范围为10~200 pmol/L,检出限3.2 pmol/L。该磁性DNA分子机器在低丰度DNA检测中具有良好的应用前景。