Zheng Jiwen, Lukeman Philip S, Sherman William B, Micheel Christine, Alivisatos A Paul, Constantinou Pamela E, Seeman Nadrian C
Department of Chemistry, New York University, New York, New York 10003, USA.
Biophys J. 2008 Oct;95(7):3340-8. doi: 10.1529/biophysj.108.138479. Epub 2008 Jul 11.
Branched DNA motifs can be designed to assume a variety of shapes and structures. These structures can be characterized by numerous solution techniques; the structures also can be inferred from atomic force microscopy of two-dimensional periodic arrays that the motifs form via cohesive interactions. Examples of these motifs are the DNA parallelogram, the bulged-junction DNA triangle, and the three-dimensional-double crossover (3D-DX) DNA triangle. The ability of these motifs to withstand stresses without changing geometrical structure is clearly of interest if the motif is to be used in nanomechanical devices or to organize other large chemical species. Metallic nanoparticles can be attached to DNA motifs, and the arrangement of these particles can be established by transmission electron microscopy. We have attached 5 nm or 10 nm gold nanoparticles to every vertex of DNA parallelograms, to two or three vertices of 3D-DX DNA triangle motifs, and to every vertex of bulged-junction DNA triangles. We demonstrate by transmission electron microscopy that the DNA parallelogram motif and the bulged-junction DNA triangle are deformed by the presence of the gold nanoparticles, whereas the structure of the 3D-DX DNA triangle motif appears to be minimally distorted. This method provides a way to estimate the robustness and potential utility of the many new DNA motifs that are becoming available.
分支DNA基序可以设计成呈现多种形状和结构。这些结构可以通过多种溶液技术进行表征；也可以从基序通过内聚相互作用形成的二维周期性阵列的原子力显微镜图像中推断出这些结构。这些基序的例子有DNA平行四边形、凸起连接DNA三角形和三维双交叉（3D-DX）DNA三角形。如果要将这些基序用于纳米机械设备或组织其他大型化学物种，那么它们在不改变几何结构的情况下承受应力的能力显然是令人感兴趣的。金属纳米颗粒可以附着在DNA基序上，并且这些颗粒的排列可以通过透射电子显微镜确定。我们已经将5纳米或10纳米的金纳米颗粒附着到DNA平行四边形的每个顶点、3D-DX DNA三角形基序的两个或三个顶点以及凸起连接DNA三角形的每个顶点上。我们通过透射电子显微镜证明，DNA平行四边形基序和凸起连接DNA三角形会因金纳米颗粒的存在而变形，而3D-DX DNA三角形基序的结构似乎只有最小程度的扭曲。这种方法提供了一种途径来估计许多新出现的DNA基序的稳健性和潜在用途。
