Approaching the limit: Can one DNA oligonucleotide assemble into large nanostructures?
Approaching the limit: Can one DNA oligonucleotide assemble into large nanostructures?
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DOI：
10.1002/anie.200504022
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发表时间：
2006-01-01
影响因子：
16.6
通讯作者：
Mao, CD
中科院分区：
文献类型：
--
作者：
Liu, HP;Chen, Y;Mao, CD
1942 2006 Wiley-VCH Verlag GmbH & Co. KGaA，Weinheim Angew。化学。国际。埃德。 2006, 45, 1942–1945 许多微米长。 DNA 纳米管已通过包含多种不同 DNA 链的系统的各种策略进行组装，并且需要仔细的比例校准。例如，双交叉 (DX) 分子包含 4 或 5 条 DNA 链，[5] 三重交叉 (TX) 分子包含 4 条链，[6] 交叉分子包含 9 条链，[7] 六螺旋束包含 20 条链。 [8]为了减少涉及的链数并避免比例校准，分子设计的关键是序列对称性。 [9]在我们的研究中，使用了类似双交换 (DX) 的结构（图 1），其中包含两条相同的 52 个核苷酸 (nt) 长链。该链由四个片段组成，分别长 10、16、16 和 10 个碱基。每个片段都是一个回文，因此是自补的。在天然条件下，两条链将彼此结合形成双链复合物。该复合物包含两个双链结构域和四个单链突出端。该复合物将通过单链突出端之间的杂交进一步组装成二维晶格。由于交叉点处存在许多缺口，因此二维晶格并不坚硬，可以折叠成管状。从二维晶格折叠成管是一个复合体内过程，而从小的二维晶格生长成大的扩展二维晶格是一个复合体间过程。在低 DNA 浓度（约 1 μm）下，管的形成在动力学上比大的扩展二维晶格的形成更有利。因此，DNA纳米管（螺旋或非螺旋）有望成为DNA自组装的主要产物。组装的DNA样品通过文献方法通过原子力显微镜（AFM）进行表征。 [9]纯化后，将DNA链溶解在含有Mg2+离子的中性缓冲液中。通过从958℃缓慢冷却至48℃来进行自组装（详细信息参见实验部分）。然后将样品吸收到云母表面上进行 AFM 成像。长 DNA 纳米管清晰可见（图 2）。它们的长度可达 60 微米，高度约为 6 纳米。它们的宽度在 30-70nm 之间变化。
1942 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Angew. Chem. Int. Ed. 2006, 45, 1942–1945 many micrometers long. DNA nanotubes have been assembled with various strategies from systems that contain several different DNA strands and require careful ratio calibration. For example, a double crossover (DX) molecule contains four or five DNA strands,[5] a triple crossover (TX) molecules contains four strands,[6] a cross molecule contains nine strands,[7] and a six-helix bundle contains 20strands.[8] To reduce the number of strands involved and avoid ratio calibration, the key to the molecular design is sequence symmetry.[9] In our study, a double crossover (DX)-like structure is used (Figure1), which contains two identical, 52-nucleotide (nt) long strands. The strand consists of four segments, which are 10, 16, 16, and 10 bases long, respectively. Each segment is a palindrome, thus self-complementary. At native condition, two strands will associate with each other to form a two-stranded complex. The complex contains two duplex domains and four single-stranded overhangs. The complex will further assemble into 2D lattices through hybridization between the single-stranded overhangs. Because many nicks exist at the crossover points, the 2D lattices are not stiff and could fold into tubes. The folding from 2D lattices into tubes is an intracomplex process, whereas the growth from small 2D lattices into large extended 2D lattices is an intercomplex process. At the low DNA concentration (around 1 μm), the tube formation would be kinetically more favorable than formation of large extended 2D lattices. Hence, DNA nanotubes (helical or non-helical) are expected to be primary products from the DNA selfassembly.Assembled DNA samples were characterized by atomic force microscopy (AFM) by literature methods.[9] After purification, the DNA strand was dissolved in a neutral buffer containing Mg2+ ions. Self-assembly was performed by slowly cooling from 958C to 48C (see Experimental Section for details). Then the samples were absorbed onto mica surfaces for AFM imaging. Long DNA nanotubes can be clearly visualized (Figure 2). They are up to 60 μm long and around 6nm high. Their width varies between 30–70nm.