DNA Origami Scaffolds as Templates for Functional Tetrameric Kir3 K+ Channels

In native systems, scaffolding proteins play important roles in assembling proteins into complexes to transduce signals. This concept is yet to be applied to the assembly of functional transmembrane protein complexes in artificial systems. To address this issue, DNA origami has the potential to serve as scaffolds that arrange proteins at specific positions in complexes. Herein, we report that Kir3 K⁺ channel proteins are assembled through zinc‐finger protein (ZFP)‐adaptors at specific locations on DNA origami scaffolds. Specific binding of the ZFP‐fused Kir3 channels and ZFP‐based adaptors on DNA origami were confirmed by atomic force microscopy and gel electrophoresis. Furthermore, the DNA origami with ZFP binding sites nearly tripled the K⁺ channel current activity elicited by heterotetrameric Kir3 channels in HEK293T cells. Thus, our method provides a useful template to control the oligomerization states of membrane protein complexes in vitro and in living cells.     

利用DNA折纸术构建功能纳米材料

DNA折纸术(DNA origami)作为一种精确高效的自组装技术,自2006年Rothemund发明以来在生物医药、高灵敏度检测、纳米光电子器件、等离子体光子学等领域展现出巨大的应用潜力,近年来受到广大研究者的高度关注。 利用DNA折纸术构建纳米材料是以DNA origami结构为载体,通过碱基互补配对的原则及三维结构上可程序化设计和可寻址的特点精确地组装很多功能基团如金属及半导体纳米颗粒,蛋白质和单壁碳纳米管等,并应用于研究无标记的RNA杂交检测、单分子的化学反应、检测间距对多价态的配位体-蛋白质之间键合的影响等。本文对近几年来DNA origami构建功能纳米材料的研究进展加以系统综述,并对DNA origami的发展方向和应用前景进行了展望。     

模板及其在纳米材料合成领域的应用

模板法是合成纳米材料的重要方法之一.本文综述了模板的分类、制备方法、性能以及在纳米材料合成领域中的应用,并对模板合成的未来发展进行了展望。     

Photoresponsive DNA Nanocapsule Having an Open/Close System for Capture and Release of Nanomaterials

A photofunctionalized square bipyramidal DNA nanocapsule (NC) was designed and prepared for the creation of a nanomaterial carrier. Photocontrollable open/close system and toehold system were introduced into the NC for the inclusion and release of a gold nanoparticle (AuNP) by photoirradiation and strand displacement. The reversible open and closed states were examined by gel electrophoresis and atomic force microscopy (AFM), and the open behavior was directly observed by high‐speed AFM. The encapsulation of the DNA‐modified AuNP within the NC was carried out by hybridization of a specific DNA strand (capture strand), and the release of the AuNP was examined by addition of toehold‐containing complementary DNA strand (release strand). The release of the AuNP from the NC was achieved by the opening of the NC and subsequent strand displacement.     

DNA Origami Rotaxanes: Tailored Synthesis and Controlled Structure Switching

Mechanically interlocked supramolecular assemblies are appealing building blocks for creating functional nanodevices. Herein, we describe the multistep assembly of large DNA origami rotaxanes that are capable of programmable structural switching. We validated the topology and structural integrity of these rotaxanes by analyzing the intermediate and final products of various assembly routes by electrophoresis and electron microscopy. We further analyzed two structure‐switching behaviors of our rotaxanes, which are both mediated by DNA hybridization. In the first mechanism, the translational motion of the macrocycle can be triggered or halted at either terminus. In the second mechanism, the macrocycle can be elongated after completion of the rotaxane assembly, giving rise to a unique structure that is otherwise difficult to access.     

介孔碳纳米材料的制备与改性

介孔碳纳米材料因具有快速传输通道、优异的导电性、极高的比表面积和出色的化学稳定性在众多领域受到广泛关注.实现介孔碳纳米材料的可控制备和精准改性是当前的研究热点和重点.基于此,本文分析总结了这类材料的制备和改性方法,并讨论了存在的问题和未来研究方向.     

钛铁矿型CoTiO3纳米材料的制备及性能表征

以Co(NO₃)₂•6H₂O和TiO₂ (P-25)为原料, 在十六烷基三甲基溴化铵(CTAB)/水形成的胶束溶液中, 首先制得纳米氧化钴Co₃O₄-TiO₂复合材料, 该复合材料经600和700 ℃煅烧后制备了钛铁矿型CoTiO₃纳米材料. 以X射线衍射(XRD)、透射电子显微镜(TEM)、紫外-可见(UV-vis)、拉曼(Raman)光谱和X射线光电子能谱(XPS)对其结构特征和光谱性能进行了研究. 用TEM形貌观察, 粒子基本为球形; 纳米CoTiO₃的UV-vis吸收峰明显红移; 经Raman光谱和XPS分析, 进一步表明600和700 ℃煅烧后形成了Ti—O—Co键.     

DNA-二维纳米片层材料传感平台的构建及其应用

DNA-二维纳米片层材料传感平台结合DNA分子特异性识别能力与二维纳米片层材料优越的物理、化学特性,已成为化学/生物传感器领域重要的研究方向之一.鉴于二维纳米片层材料领域的快速发展,首先介绍了DNA-二维纳米片层材料传感平台的构筑机理,随后重点综述了该传感平台在化学、生物目标物分析检测中的应用研究,并对该类传感平台的应用前景做了展望.     

二维金属纳米材料的合成及电催化应用的研究进展

基于各种电化学过程的能源转化技术是未来可持续能源利用和发展的关键, 而催化剂在其中扮演着非常重要的角色. 二维金属纳米材料因其独特的物理化学性质在许多电催化反应中都展现出巨大的应用潜力, 也因此受到了广泛关注. 本文介绍了二维金属纳米材料的常见合成方法与策略, 并综合评述了近年来该类材料在电催化应用领域中的研究进展, 重点探讨了材料的组分和微观结构等因素对其性能的影响机理, 最后对二维金属纳米材料目前所面临的挑战以及未来的研究方向进行了总结与展望.     

Self-assembly of Micrometer-long DNA Nanoribbons with Four Oligonucleotides

DNA nanostructures have found widespread applications in areas including nanoelectronics and biomedicine. However, traditional DNA origami needs a long single‐stranded virus DNA and hundreds of short DNA strands, which make this method complicated and money‐consuming. Here, we present a protocol for the assembly of DNA nanoribbons with only four oligonucleotides. DNA nanoribbons with different dimensions were successfully assembled with a 96‐base scafford strand and three short staples. These biotinylated nanoribbons could also be decorated with streptavidins. This approach suggests that there exist great design spaces for the creation of simple nucleic acid nanostructures which could facilitate their application in plasmonic or drug delivery.     

六方相磷酸铈一维纳米材料的合成与表征

以磷酸钠、硝酸铈为原料, 利用P123表面活性剂的水溶液形成的胶束为反应模板, 采用水热法合成工艺, 在反应溶液的pH＝1, 反应温度为140 ℃, 反应时间为24 h的条件下成功合成了六方相的CePO4一维纳米发光材料, 并提出其可能的形成机理. 通过XRD, TEM, FT-IR, UV-Vis, PL测试表征, 发现制备的磷酸铈一维纳米材料最长可以达到1 μm左右, 而直径为10～25 nm, 轴径比较高; 其在紫外光区的荧光发射性能与普通的纳米颗粒相比得到了很大程度的提高; 六方相磷酸铈一维纳米材料以其独特的荧光发射性能, 有望在光、电等领域发挥其潜在的应用价值.     

Fluorescence Microscopy with 6 nm Resolution on DNA Origami

Resolution of emerging superresolution microscopy is commonly characterized by the width of a point‐spread‐function or by the localization accuracy of single molecules. In contrast, resolution is defined as the ability to separate two objects. Recently, DNA origamis have been proven as valuable scaffold for self‐assembled nanorulers in superresolution microscopy. Here, we use DNA origami nanorulers to overcome the discrepancy of localizing single objects and separating two objects by resolving two docking sites at distances of 18, 12, and 6 nm by using the superresolution technique DNA PAINT(point accumulation for imaging in nanoscale topography). For the smallest distances, we reveal the influence of localization noise on the yield of resolvable structures that we rationalize by Monte Carlo simulations.     

Orthogonal Protein Assembly on DNA Nanostructures Using Relaxases

DNA‐binding proteins are promising reagents for the sequence‐specific modification of DNA‐based nanostructures. Here, we investigate the utility of a series of relaxase proteins—TrwC, TraI, and MobA—for nanofunctionalization. Relaxases are involved in the conjugative transfer of plasmids between bacteria, and bind to their DNA target sites via a covalent phosphotyrosine linkage. We study the binding of the relaxases to two standard DNA origami structures—rodlike six‐helix bundles and flat rectangular origami sheets. We find highly orthogonal binding of the proteins with binding yields of 40–50 % per binding site, which is comparable to other functionalization methods. The yields differ for the two origami structures and also depend on the position of the binding sites. Due to their specificity for a single‐stranded DNA target, their orthogonality, and their binding properties, relaxases are a uniquely useful addition to the toolbox available for the modification of DNA nanostructures with proteins.     

生物分子辅助的纳米材料绿色合成

纳米材料绿色合成的标准是合成需使用对环境无污染的溶剂体系、还原剂以及无毒的稳定剂来进行.生物分子具备有机和无机质导向生成的能力,且具有热和化学稳定性、容易获得、价格便宜,最重要的是对环境无污染,可用于纳米材料的绿色制备.本文就笔者在生物分子辅助绿色合成纳米材料方面的研究成果做一汇总和介绍.     

Zn_2SnO_4纳米材料制备及光致发光特性

以ZnO、SnO2和活性炭的混合物为原料,通过碳热还原热蒸发法无催化剂成功制备出Zn2SnO4纳米材料.借助X射线衍射仪(XRD)、拉曼光谱和扫描电子显微镜(SEM)对样品物相和形貌进行了表征,结果显示样品为面心立方结构的Zn2SnO4纳米链状棒,同时含有少量的ZnO物相.利用X射线光电子能谱(XPS)对Zn2SnO4样品表面各元素的化学状态及相互作用方式进行了测试,结果表明:样品中Zn和Sn分别是以+2价和+4价氧化态形式存在,其中Zn2p3/2电子有两个结合能,分别来自ZnO和Zn2SnO4,Zn2SnO4中Sn4+占据不同的格点位置.室温下光致发光谱(PL)结果显示,样品在紫外区域(320-450nm)和可见区域存在很强的发光带,其中紫外区域的宽发光带,经过高斯拟合可分为358和385nm两个发光峰,与同条件下制备得到的纯ZnO纳米材料发光谱比较,确认358nm发光峰是来自于Zn2SnO4的近带边复合发光.     

Photocontrolled Dopamine Polymerization on DNA Origami with Nanometer Resolution

Temporal and spatial control over polydopamine formation on the nanoscale can be achieved by installing an irradiation‐sensitive polymerization system on DNA origami. Precisely distributed G‐quadruplex structures on the DNA template serve as anchors for embedding the photosensitizer protoporphyrin IX, which—upon irradiation with visible light—induces the multistep oxidation of dopamine to polydopamine, producing polymeric structures on designated areas within the origami framework. The photochemical polymerization process allows exclusive control over polydopamine layer formation through the simple on/off switching of the light source. The obtained polymer–DNA hybrid material shows significantly enhanced stability, paving the way for biomedical and chemical applications that are typically not possible owing to the sensitivity of DNA.     

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。     

Surface‐Assisted Large‐Scale Ordering of DNA Origami Tiles

The arrangement of DNA‐based nanostructures into extended higher order assemblies is an important step towards their utilization as functional molecular materials. We herein demonstrate that by electrostatically controlling the adhesion and mobility of DNA origami structures on mica surfaces by the simple addition of monovalent cations, large ordered 2D arrays of origami tiles can be generated. The lattices can be formed either by close‐packing of symmetric, non‐interacting DNA origami structures, or by utilizing blunt‐end stacking interactions between the origami units. The resulting crystalline lattices can be readily utilized as templates for the ordered arrangement of proteins.