UK researchers have developed a tiny turbine composed of nested carbon nanotubes. Even though the design is currently only theoretical, many uses having already been suggested for the nanoscale rotor, including in a novel kind of computer memory. The researchers have also suggested that the turbine could be used in a sort of “inkjet” printer for nanofabrication.
But there are possibilities beyond spraying nanoparticles on a surface. If arms were attached to two counter-rotating turbines, then they could be used to forcefully bring molecular components together—mechanosynthesis. It’s probably not possible to make diamondoid structures this way, but there are plenty of other things you could make. After all, we know that this is possible on some level because it’s very similar to how cells form the high energy bond in ATP.
Nanodot has an excellent overview of the advances in DNA-based nanoscale assembly that I discussed recently. The Nanodot piece not only summarizes the breakthroughs, it also does a good job of presenting their limitations.
I’m pretty skeptical about so-called “bottom-up” approaches to nanoscale assembly. Such techniques aim to create tiny structures via the precise positioning of individual atoms. Indeed, molecular assembly is the holy grail of nanotechnology, but many scientists think it’s a pipe dream. The only way I can envision bottom-up assembly working is if we take a lesson from nature and emulate or engineer the machinery of cells to do the work for us.
Now, two separate teams of researchers have recently reported on ways to use DNA to construct nanoscale structures. A team at Texas A&M used DNA as a template to create nanowires made from cadmium while researchers at Northwestern University created different arrangements of gold atoms. The cadmium nanowires could be used in advanced electronics or implantable medical devices. The structure of gold don’t suggest an immediate application, but they represent an important step on the path to being able to build complex nanostructures.
While we normally think of DNA as a very long string, it can also be used to form very complex structures such as a truncated octahedron. Thus very complex nanostructures are possible. Molecular assembly as envisioned as envisioned by the pioneers of nanotechnology may not be possible, but we may nonetheless be able to achieve bottom-up assembly by stealing from nature. The possibilities are limitless.
