Mechanical metamaterials consist of periodic structures with enhanced material properties. The best additive manufacturing techniques have resolutions of 100s of nanometers, which cannot fully realize material size effects. Further, they cannot easily combine disparate materials (e.g., soft, biological polymers with hard ceramics). Here, DNA origami is used to construct octahedral-based isotropic and anisotropic nanolattices, which are coated with silica. These DNA nanolattices have features two orders of magnitude smaller than additively manufactured lattices and obtain material properties comparable to the best nanolattices due to material size effects. Atom probe tomography confirms the nanoscale distribution of DNA and silica in the octahedral lattice. Finite element modeling reveals two dominate failure modes: buckling at lower coating thicknesses and tensile fracture at higher thicknesses. Molecular dynamics simulations reveal that the DNA suppresses global buckling modes in favor of surface buckling, which delays failure and contributes to increased strength at large strains.

机械超材料由具有增强材料特性的周期性结构组成。最好的增材制造技术的分辨率为数百纳米，无法完全实现材料尺寸效应。此外，它们不能轻易地将不同的材料（例如，软质生物聚合物与硬质陶瓷）结合起来。在这里，DNA折纸用于构建基于八面体的各向同性和各向异性纳米晶格，并涂有二氧化硅。这些 DNA 纳米晶格的特征比增材制造的晶格小两个数量级，并且由于材料尺寸效应而获得与最佳纳米晶格相当的材料性能。原子探针断层扫描证实了 DNA 和二氧化硅在八面体晶格中的纳米级分布。有限元建模揭示了两种主要的失效模式：较低涂层厚度下的屈曲和较高厚度下的拉伸断裂。分子动力学模拟表明，DNA 抑制全局屈曲模式，有利于表面屈曲，从而延迟失效并有助于提高大应变下的强度。