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One of the applications of the ordered DNA origami arrays is its use as a “scaffold” to organize a variety of particles such as proteins [58, 64, 66], metal inorganic particles [53], and other nanoscale objects. In the example shown in Figure 3.5, the internal cavities of a preassembled two‐dimensional DNA origami lattice were used to incorporate “supplemental” DNA origami nanostructures with shapes that were complementary to those of the cavities [67]. The lattice was first self‐assembled from cross‐shaped DNA origamis on a mica‐supported DOPC lipid bilayer membrane and subsequently exposed to square‐shaped origamis. Successive time‐lapse AFM at 10 mM Mg²⁺ revealed the squares have a dynamic adsorption/desorption behavior, wherein arrangements in the assembled lattice contentiously changed, suggesting that they indeed accessed the cavities, but were not stably trapped in them (Figure 3.5a).

This dynamic feature revealed by HS‐AFM provided a clue that allowed a chequerboard‐like pattern to be derived from the lattice structure via sequential self‐assembly (Figure 3.5b). To realize this pattern derivation, a two‐dimensional lattice wherein every other cavity has polyT strands was first self‐assembled from two types of cross‐shaped DNA origamis. Then, the square origami carrying polyA strands at its four corners was loaded onto the preassembled lattice. The polyA‐modified squares that entered correct positions (cavities with 8T strands) could be docked in the cavity by sticky‐ended cohesion despite insufficient adsorption onto the membrane surface, whereas those that entered false positions (cavities without 8T linkers) could desorb from the cavity. Hence, the square origami would be finally incorporated only in the correct positions to make a chequerboard‐like pattern as demonstrated in HS‐AFM images (Figure 3.5c).

Figure 3.5 Placing square‐shaped DNA origami into lipid bilayer‐supported 2D lattices. (a) Dynamic docking events of square‐shaped origamis into the 2D lattice cavities recorded at a scan rate of 0.2 fps. Scale bar = 200 nm. (b) Schematic representation of the sequential self‐assembly and directed placement of square‐shaped origamis to produce a chequerboard‐like pattern. The streptavidin‐modified cross A and cross B were self‐assembled into a framework structure. Topographic AFM images of the assembled chequerboard‐like pattern is also shown. (c) Dynamic rearrangement of square‐shaped origami on the false positions (dashed circles) and docking into a correct position (dashed square). Edge reorganization was also occurred in the area enclosed in orange dotted lines. Scale bar = 200 nm.

Source: Suzuki et al. [67]/with permission from John Wiley & Sons, Inc.