DNA origami methods enable the fabrication of various nanostructures and nanodevices, but their effective use depends on an understanding of their structural and mechanical properties and the effects of basic structural features. Frequency‐modulation atomic force microscopy is introduced to directly characterize, in aqueous solution, the crossover regions of sets of 2D DNA origami based on different crossover/nick designs. Rhombic‐shaped nanostructures formed under the influence of flexible crossovers placed between DNA helices are observed in DNA origami incorporating crossovers every 3, 4, or 6 DNA turns. The bending rigidity of crossovers is determined to be only one‐third of that of the DNA helix, based on interhelical electrostatic forces reported elsewhere, and the measured pitches of the 3‐turn crossover design rhombic‐shaped nanostructures undergoing negligible bending. To evaluate the robustness of their structural integrity, they are intentionally and simultaneously stressed using force‐controlled atomic force microscopy. DNA crossovers are verified to have a stabilizing effect on the structural robustness, while the nicks have an opposite effect. The structural and mechanical properties of DNA origami and the effects of crossovers and nicks revealed in this paper can provide information essential for the design of versatile DNA origami structures that exhibit specified and desirable properties.

中文翻译：

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用不同的交叉/尼克设计构建的二维DNA折纸的菱形纳米结构和力学性能

DNA折纸方法可以制造各种纳米结构和纳米器件，但其有效使用取决于对它们的结构和机械性能以及基本结构特征的影响的理解。引入了调频原子力显微镜，可根据水溶液中的不同交叉/缺口设计，直接表征水溶液中2D DNA折纸组的交叉区域。在DNA折纸中，每3、4或6个DNA转折点就会出现菱形形状的纳米结构，这些结构是在DNA螺旋之间放置的灵活交叉点的影响下形成的。根据其他地方报道的螺旋间静电力，确定交叉的弯曲刚度仅为DNA螺旋刚度的三分之一，3圈交叉设计菱形纳米结构的弯曲度可忽略不计。为了评估其结构完整性的稳健性，使用力控制原子力显微镜对它们进行有意并同时受力。DNA交换被证明对结构坚固性具有稳定作用，而缺口则具有相反的作用。本文中揭示的DNA折纸的结构和机械性能以及交叉和切口的影响可以为设计具有特定和理想特性的多功能DNA折纸结构提供必要的信息。DNA交换被证明对结构坚固性具有稳定作用，而缺口则具有相反的作用。本文中揭示的DNA折纸的结构和机械性能以及交叉和切口的影响可以为设计具有特定和理想特性的多功能DNA折纸结构提供必要的信息。DNA交换被证明对结构坚固性具有稳定作用，而缺口则具有相反的作用。本文中揭示的DNA折纸的结构和机械性能以及交叉和切口的影响可以为设计具有特定和理想特性的多功能DNA折纸结构提供必要的信息。