可控自组装DNA折纸结构作为药物载体的研究进展

在过去的几十年里, DNA纳米技术作为一种快速发展的可控自组装技术, 使人们能构建出各种复杂的纳米结构. DNA折纸结构具备可编程性、 空间可寻址性、 易修饰性及良好的生物相容性等多种优越的特性, 这些优异的性质使其在药物递送方面具有广阔的应用前景. 本文总结了近年来可控自组装DNA折纸结构作为药物递送系统的研究进展, 展望了DNA折纸纳米载体未来的发展方向, 并讨论了该领域面临的挑战和可能的解决方法.     

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。     

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。     

DNA折纸术纳米反应器

基于DNA折纸技术,构建具有纳米尺度可寻址的新型DNA纳米反应器,是DNA纳米技术领域的一个最新研究思路和方向。它的优势首先在于其纳米定位能力,通过不同的化学或生物相互作用,已能够实现对包括化学小分子、生物大分子及人工纳米材料等的纳米级精确定位;其次,DNA折纸结构的丰富多样性,使构建纳米级仿生限域环境成为了可能;此外,DNA折纸结构本身的生物相容性及优良的产率,也保证了这一材料的可应用性。本文首先介绍了在DNA折纸结构上,对不同材料和分子进行纳米定位的一般方法和最新进展。然后,着重阐述了基于纳米定位技术,以DNA折纸结构作为纳米反应器,对一些化学、生化反应的成功调控。最后,基于现有的工作基础,我们提出了DNA折纸术纳米反应器概念在未来的发展方向及应用前景展望。     

框架核酸在蛋白精确组装中的应用

除了作为遗传信息的载体,DNA所展现出的特殊材料性能引起了广泛关注。基于碱基互补配对原则的精确性和可编程性使得核酸纳米结构的构建逐步从一维单链发展到二维平面以及三维立体结构。计算机辅助工具的进步也促进了各种大小和形状的DNA纳米结构的自动化设计,而近年来构建的"框架核酸(FNAs)"为生物大分子纳米尺度上的精确排列提供了新方法,其固有的生物学功能以及可定制的特性使得其在物理、化学和生物等领域具有十分广阔的应用前景。本文阐述了精确自组装的FNAs的概念,并概述了FNAs在蛋白精确组装等领域的最新进展;重点论述了FNAs的优势所带来的对蛋白空间排布及其性能的调控能力,讨论了该领域存在的挑战,并对其发展机遇进行了展望。     

DNA纳米机器

本文介绍了以DNA为基础的纳米机器的发展现状,强调了核酸作为一种材料在纳米科技领域的重要作用.着重阐述了利用链交换反应或环境因素变化可以驱动DNA二级结构的变化,从而可以构建出形式多样的纳米级核酸分子机器;评价了各类分子机器在效率、寿命和副产物方面的优缺点.在总结前人工作的基础上预测了核酸纳米技术在生命科学、材料科学以及计算科学等诸多方面可能的应用.     

DNA发夹结构自组装信号放大策略应用的研究进展

DNA发夹结构自组装因具有无酶参与、等温以及识别序列能力强等优点,在生物分子和金属离子检测方面展现了良好的发展前景。该文梳理了DNA发夹结构自组装信号放大策略的类型,综述了近年来该策略在致病菌、核酸肿瘤标记物、蛋白质、无机金属离子,以及生物小分子检测中应用的研究进展,并对其未来发展趋势进行了展望,旨在为基于DNA发夹结构自组装检测生物分子提供一定的参考。     

Reconfigurable T-junction DNA Origami

DNA self-assembly allows the construction of nanometre-scale structures and devices. Structures with thousands of unique components are routinely assembled in good yield. Experimental progress has been rapid, based largely on empirical design rules. Herein, we demonstrate a DNA origami technique designed as a model system with which to explore the mechanism of assembly. The origami fold is controlled through single-stranded loops embedded in a double-stranded DNA template and is programmed by a set of double-stranded linkers that specify pairwise interactions between loop sequences. Assembly is via T-junctions formed by hybridization of single-stranded overhangs on the linkers with the loops. The sequence of loops on the template and the set of interaction rules embodied in the linkers can be reconfigured with ease. We show that a set of just two interaction rules can be used to assemble simple T-junction origami motifs and that assembly can be performed at room temperature.     

Reconfigurable T‐junction DNA Origami

DNA self‐assembly allows the construction of nanometre‐scale structures and devices. Structures with thousands of unique components are routinely assembled in good yield. Experimental progress has been rapid, based largely on empirical design rules. Herein, we demonstrate a DNA origami technique designed as a model system with which to explore the mechanism of assembly. The origami fold is controlled through single‐stranded loops embedded in a double‐stranded DNA template and is programmed by a set of double‐stranded linkers that specify pairwise interactions between loop sequences. Assembly is via T‐junctions formed by hybridization of single‐stranded overhangs on the linkers with the loops. The sequence of loops on the template and the set of interaction rules embodied in the linkers can be reconfigured with ease. We show that a set of just two interaction rules can be used to assemble simple T‐junction origami motifs and that assembly can be performed at room temperature.     

3D Framework DNA Origami with Layered Crossovers

Designer DNA architectures with nanoscale geometric controls provide a programmable molecular toolbox for engineering complex nanodevices. Scaffolded DNA origami has dramatically improved our ability to design and construct DNA nanostructures with finite size and spatial addressability. Here we report a novel design strategy to engineer multilayered wireframe DNA structures by introducing crossover pairs that connect neighboring layers of DNA double helices. These layered crossovers (LX) allow the scaffold or helper strands to travel through different layers and can control the relative orientation of DNA helices in neighboring layers. Using this design strategy, we successfully constructed four versions of two‐layer parallelogram structures with well‐defined interlayer angles, a three‐layer structure with triangular cavities, and a 9‐ and 15‐layer square lattices. This strategy provides a general route to engineer 3D framework DNA nanostructures with controlled cavities and opportunities to design host–guest networks analogs to those produced with metal organic frameworks.     

DNA Origami Post‐Processing by CRISPR‐Cas12a

Customizable nanostructures built through the DNA‐origami technique hold tremendous promise in nanomaterial fabrication and biotechnology. Despite the cutting‐edge tools for DNA‐origami design and preparation, it remains challenging to separate structural components of an architecture built from—thus held together by—a continuous scaffold strand, which in turn limits the modularity and function of the DNA‐origami devices. To address this challenge, here we present an enzymatic method to clean up and reconfigure DNA‐origami structures. We target single‐stranded (ss) regions of DNA‐origami structures and remove them with CRISPR‐Cas12a, a hyper‐active ssDNA endonuclease without sequence specificity. We demonstrate the utility of this facile, selective post‐processing method on DNA structures with various geometrical and mechanical properties, realizing intricate structures and structural transformations that were previously difficult to engineer. Given the biocompatibility of Cas12a‐like enzymes, this versatile tool may be programmed in the future to operate functional nanodevices in cells.     

Multifunctional DNA Origami Nanoplatforms for Drug Delivery

DNA nanotechnology has been employed in the construction of self‐assembled nano‐biomaterials with uniform size and shape for various biological applications, such as bioimaging, diagnosis, or therapeutics. Herein, recent successful efforts to utilize multifunctional DNA origami nanoplatforms as drug‐delivery vehicles are reviewed. Diagnostic and therapeutic strategies based on gold nanorods, chemotherapeutic drugs, cytosine–phosphate–guanine, functional proteins, gene drugs, and their combinations for optoacoustic imaging, photothermal therapy, chemotherapy, immunological therapy, gene therapy, and coagulation‐based therapy are summarized. The challenges and opportunities for DNA‐based nanocarriers for biological applications are also discussed.     

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.     

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.     

Scaling Up DNA Origami Lattice Assembly

The surface-assisted hierarchical assembly of DNA origami nanostructures is a promising route to fabricate regular nanoscale lattices. In this work, the scalability of this approach is explored and the formation of a homogeneous polycrystalline DNA origami lattice at the mica-electrolyte interface over a total surface area of 18.75 cm² is demonstrated. The topological analysis of more than 50 individual AFM images recorded at random locations over the sample surface showed only minuscule and random variations in the quality and order of the assembled lattice. The analysis of more than 450 fluorescence microscopy images of a quantum dot-decorated DNA origami lattice further revealed a very homogeneous surface coverage over cm² areas with only minor boundary effects at the substrate edges. At total DNA costs of € 0.12 per cm², this large-scale nanopatterning technique holds great promise for the fabrication of functional surfaces.