Fig. 1: Inverse design and assembly of hierarchically ordered 3D nanostructures through voxels encoded with chromatic and directional bonds.
From: Encoding hierarchical 3D architecture through inverse design of programmable bonds
a, A desired 3D hierarchically ordered crystal of nanocomponents can be constructed from material voxels, consisting of a DNA frame that provides intervoxel chromatic binding and valence-defined coordination of bonds for internally bound components. The set of voxels defines a prescribed repetitive motif, or mesovoxel, which is a hierarchical unit block. A mesovoxel consists of a voxel set that can undergo spatial transformations, associated with symmetries of the target organization of NPs, to hierarchically construct a 3D crystal using three tiers of chromatic bond descriptors: Via, Vmb and Vec. Background voxels are paler with no chromatic bonds shown to improve image clarity, but they possess their own binding colours in practice, as discussed in the text. Experimental implementation of this schematic concept uses a DNA origami octahedron as the voxel and Au NPs functionalized with different ssDNA coronas as the internally bound nanocomponents. In the schematic representation, bond colours (subscripts a, b, c) are represented as either standalone integers or in combination with a ‘C’ to represent a bond colour complement. b, A range of 3D NP crystals are explored in this work, all synthesized by implementing chromatic binding in a simple cubic grid built from DNA octahedra, as shown in the scanning electron microscopy (SEM) images (left). NP organizations are shown on the right, next to a corresponding repetitive motif.
