Lipid DNA origami may lead to advanced future nanomachines

September 8, 2015

Using a double layer of lipids facilitates assembly of DNA origami nanostructures, bringing us one step closer to future DNA nanomachines, as in this artist’s impression (credit: Kyoto University’s Institute for Integrated Cell-Material Sciences)

Kyoto University scientists in Japan have developed a method for creating larger 2-D self-assembling DNA origami* nanostructures.

Current DNA origami methods can create extremely small two- and three-dimensional shapes that could be used as construction material to build nanodevices, such as nanomotors, in the future for targeted drug delivery inside the body, for example. KurzweilAI recently covered advanced methods developed by Brookhaven National Laboratory and  Arizona State University’s Biodesign Institute.

Lipid bilayer allows DNA origami structures to easily self-assemble into 2-D nanostructures (credit: Yuki Suzuki et al./Nature Communications)

Unlike those rigid structures, the Kyoto scientists used a double layer of lipids (fats) containing both a positive and a negative charge. That caused the DNA origami structures to be absorbed onto the lipid layer via electrostatic interaction. The weak bond between the origami structures and the lipid layer allowed them to move more freely than in other approaches, facilitating their interaction with one another and allowing them to self-assemble and form larger structures.

“We anticipate that our approach will further expand the potential applications of DNA origami structures and their assemblies in the fields of nanotechnology, biophysics, and synthetic biology,” says chemical biologist Professor Hiroshi Sugiyama from Kyoto University’s Institute for Integrated Cell-Material Sciences (iCeMS).

The study was published in an open-access paper in Nature Communications on August 27, 2015.

* The technique of DNA origami capitalizes on the simple base-pairing properties of DNA, a molecule built from the four nucleotides Adenine (A)Thymine (T)Cytosine (C) and Guanine (G). The rules of the game are simple: A’s always pair with T’s and C’s with G’s. Using this abbreviated vocabulary, the myriad body plans of all living organisms are constructed; though duplicating even Nature’s simpler designs has required great ingenuity.

The basic idea of DNA origami is to use a length of single-stranded DNA as a scaffold for the desired shape. Base-pairing of complementary nucleotides causes the form to fold and self-assemble. The process is guided by the addition of shorter “staple strands,” which act to help fold the scaffold and to hold the resulting structure together. Various imaging technologies are used to observe the tiny structures, including fluorescence-, electron- and atomic-force microscopy.

Abstract of Lipid-bilayer-assisted two-dimensional self-assembly of DNA origami nanostructures

Self-assembly is a ubiquitous approach to the design and fabrication of novel supermolecular architectures. Here we report a strategy termed ‘lipid-bilayer-assisted self-assembly’ that is used to assemble DNA origami nanostructures into two-dimensional lattices. DNA origami structures are electrostatically adsorbed onto a mica-supported zwitterionic lipid bilayer in the presence of divalent cations. We demonstrate that the bilayer-adsorbed origami units are mobile on the surface and self-assembled into large micrometre-sized lattices in their lateral dimensions. Using high-speed atomic force microscopy imaging, a variety of dynamic processes involved in the formation of the lattice, such as fusion, reorganization and defect filling, are successfully visualized. The surface modifiability of the assembled lattice is also demonstrated by in situ decoration with streptavidin molecules. Our approach provides a new strategy for preparing versatile scaffolds for nanofabrication and paves the way for organizing functional nanodevices in a micrometer space.