Caltech researchers have applied DNA-based self-assembly to bind pairs of carbon nanotubes into structures that can act as field-effect transistors. Nature Nanotechnology has a prepublication release of their paper, “Self-assembly of carbon nanotubes into two-dimensional geometries using DNA origami templates”; the work emerged from a collaboration centered on the Winfree lab. Physorg.com reports the story behind the work — and on the prospects ahead, quoting William Goddard:
“This is a scalable technology. That is, one can design the origami to construct complex logic units and to do this for thousands or millions or billions of units that self-assemble in parallel.”
This achievement is a milestone in framework-directed self assembly of composite nanosystems, a line of development that I’ve argued is a strategic direction in atomically precise fabrication — useful in itself, and as part of a technology platform for further progress. In self-assembling molecular machine systems, carbon nanotubes could serve as structural components that are orders of magnitude stiffer than biomolecules, and can also serve as moving parts, including low-friction linear and rotary bearings.
In recent months, I’ve discussed breakthroughs in extending DNA origami to 3D structures: a technique for folding origami sheets to form boxes and a more radical technique for making solid DNA nanostructures. To bind nanotubes to origami structures, the Caltech team wrapped them in single strand DNA, a self-assembly technique that can make the tubes soluble. As I reported earlier, techniques based on DNA wrapping have also been used to separate nanotubes of specific types from an as-synthesized mixture.
For perspective, remember that nanolithography working at a billion-device scale requires a set of large, expensive, extraordinarily precise machines; industrial-scale fabs now cost billions of dollars. You’ll see nothing like these machines in the Winfree lab, or in the production areas of other bionanotechnology labs. Atomically precise self assembly on a billion-device scale can be done using glassware, pipettes, heaters, freezers, and the like. From an equipment point of view, the harder part is seeing the result, but for reasonably flat structures, desktop-scale AFMs can do the job.
- A DNA Origami Box
- A Third Revolution in DNA Nanotechnology
- Modular Molecular Composite Nanosystems
- Macromolecular Modeling for Molecular Systems Engineering