DNA origami is a molecular self-folding technique in which long single-stranded DNA scaffolds, typically M13 phage genomic DNA, are folded into well-defined objects by hundreds of short-stranded DNA staples in a one-pot method. The intrinsic addressability of DNA origami is achieved by supplementing different parts of the long single-stranded DNA scaffold with a unique set of DNA staples driven by Watson-Crick base-pairing of double-stranded DNA (dsDNA) hybridization without the need for restriction enzymes or DNA ligases.The concept of DNA origami was pioneered in 2006 by Rothemund, who utilized the DNA Using DNA origami, he constructed a series of two-dimensional DNA nanostructures such as triangles, pentagrams and smiley faces. This assembled DNA origami (~100 nm) exhibits a programmable pattern with a spatial resolution of 6 nm, enabling the design of more complex or larger structures. First, with bottom-up DNA origami, DNA structures are no longer limited to some simple, regular geometric patterns. Large-scale, structurally stable and arbitrary DNA shapes can be constructed, which compensates for the poor size control problems faced by DNA tiles. Second, M13 phage genomic DNA is the most commonly used scaffold for DNA origami assembly, and the corresponding peg sequences can be automatically designed based on the routing path. Finally, DNA origami assembly does not have stringent requirements on the stoichiometric ratio and purity of the DNA backbone.
Figure 1. The construction of intricate DNA origamis. (Z, M, He.; et al, 2023)
Since individual DNA origami is limited in size, two-dimensional assembly is generally used to scale up. A simple strategy for assembling single-stranded DNA into desired two-dimensional patterns was born. Staple strands in the edge portion are paired by complementary bases to produce an adjustable combination of shapes, avoiding high concentrations of aggregation by introducing a hairpin structure. This idea laid the foundation for subsequent approaches to DNA origami assembly. For example, based on the above background, the researchers proposed a method for designing large-scale 2D DNA origami using rectangular DNA tiles as staple tiles instead of using conventional staple strands. This strategy can be used to fabricate large DNA origami objects with a size range comparable to conventional lithography, thus combining bottom-up assembly with top-down lithography.
Expanding the size of DNA origami through 3D assembly can broaden the applications of DNA origami. Using reconfigurable DNA origami nanoarrays, the researchers propose a modular conversion method that enables controlled conversion from 2D structures to 3D architectures. 2D DNA structures can be modularized into multiple connected units for independent conversion, and this modular conversion also enables structural conversion between 2D and 3D nanostructures.
DNA origami allows the construction of two- and three-dimensional nanostructures with specific shapes and functions by precisely designing and controlling DNA sequences. This technique not only provides new possibilities for precise assembly at the nanoscale, but also opens up new directions for the development of nanotechnology in different fields.
Figure 2. DNA origami in nanofabrication, biosensing, drug delivery, and computational storage. (Z, M, He.; et al, 2023)
For the time being, the application of DNA origami is still in its infancy and faces some practical challenges as follows.
Several approaches, such as covalent attachment of DNA bases, protein coatings, virus-inspired membrane encapsulation, polyethylene glycol grafting, and silica coatings, have been explored to enhance the stability of DNA origami.
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