DOI: 10.5061/dryad.g4f4qrfxz
title: DNA-silica nanolattices as mechanical metamaterials

description: Mechanical metamaterials consist of intricate periodic structures made
 using additive manufacturing techniques. Yet, nanoscale (&lt;10 nm)
 features cannot be directly printed using these fabrication techniques,
 although this is the size regime in which enhanced material properties
 appear. In addition, current additive manufacturing techniques cannot
 easily combine disparate materials (e.g., soft, biological polymers with
 hard ceramics) into structural motifs. Here, we show that DNA origami can
 be used to construct octahedral-based isotropic and anisotropic
 nanolattices. When coated with a thin silica layer, these nanolattices
 obtain strength and energy absorption competitive with the best additively
 manufactured nanolattices. The DNA nanolattices have strut 6 nm diameters
 and  ~50 nm unit cells, which are two orders of magnitude smaller
 than lithography-based lattices. The silica coating is as thin as ~1.65
 nm, which results in enhanced strength. Atom probe tomography confirms the
 nanoscale distribution of DNA and silica in the octahedral lattice
 geometry. Finite element modeling (FEM) reveals two dominant failure
 modes: buckling at lower coating thicknesses and tensile fracture at
 higher thicknesses. Molecular dynamics (MD) simulations reveal that the
 DNA delays failure by suppressing buckling within the lattice struts,
 while the nanoscale silica undergoes a surface buckling mode which
 contributes to increased strength at large strains.
description: # DNA-silica nanolattices as mechanical metamaterials
 [https://doi.org/10.5061/dryad.g4f4qrfxz](https://doi.org/10.5061/dryad.g4f4qrfxz) This folder contains all data needed to reproduce the results in the paper titled "DNA-Silica Nanolattices as Mechanical Metamaterials" by Kulikowski and Wang et al. in *Matter*. Naming convention: sample names start with the heading DNAC-###-###, where the first 3 digits correspond to sets of sample preparation conditions and the second 3 digits correspond to sample numbers within those conditions. For example, DNAC-001-001 and DNAC-001-003 refer to the silica coating of 1.75nm but dispersed on 2 different silicon wafer pieces. The samples themselves should behave the same. DNAC-003-003 refers to a coating of 5.1nm on its 3rd iteration. This is NOT on the same silicon wafer piece as DNAC-001-003. Some files omit the last 3 digits. Designations are as follows: DNAC-001-###: 1.75nm coating thickness samples DNAC-002-###: space filling coating samples DNAC-003-###: 5.1nm coating thickness samples DNAC-004-###: 3.1nm coating thickness samples DNAC-005-###: space filling coating samples (distinct from DNAC-002-### in that a new batch of particles was made) DNAC-007-###: 1.65nm coating thickness samples DNAC-008-###: 2.1 coating thickness samples DNAC-ESO-###: elongated octahedral structure DNAC-FSO-### flattended octahedral structure There are subfolders: Shell thickness images - images used to find the shell thickness results RAW data - mechanical data for each test used in the analysis, note that mechanical data from DNAC-001-### through DNAC-005-### are gathered from in-situ SEM testing while DNAC-007-###, DNAC-008-###, DNAC-ESO-###, and DNAC-FSO-### are gather on a benchtop nanoindenter. * Side depth cells marked N/A are for cubes which have equal depth and length * Offset yield stresses or energy absorption marked N/A indicate that either the tests were not performed for long enough to determine these values or there are no associated videos so a point of first fracture cannot be determined. Simulations - simulation data for FEM and MD results in figure 5 of the main manuscript.