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.