How researchers tied carbon nanotubes in knots

Nano-tweezers capable of manipulating materials molecule-by-molecule, paving the way for nano-robots, have been developed in Sweden.

Nano-tweezers capable of manipulating materials molecule-by-molecule, paving the way for nano-robots, have been developed in Sweden.

The invention is a new system of carbon nanotube self-assembly – the series of chemical reactions that gives rise to nano-structures. Researchers at the Chalmers University of Technology in Gothenburg have managed to control their self-assembly process to such a degree that they have tied carbon nanotubes in knots.

This method may be used in future to manufacture nano-robots, or nano-motors used in nano-robotics, from just a handful of molecules. In their experiment, the researchers allowed nanotubes to self-assemble inside hollow, organic cells known as vesicles, floating in a specially prepared aqueous solution.

As the nanotubes formed, they self-assembled into networks, tying themselves together with other nanotubes. After these networks had formed, the researchers brought together the nanotubes that had originated from the same vesicle. These tubes formed y-structures that began to self-propagate and form self-tightening knots around other nanotubes.

By modifying the position of the cells, the researchers were able to adjust the tension and location of the knots, and in doing so the researchers managed to move and manipulate these tubes with a high degree of precision.

But Owe Orwar, professor of biophysical chemistry at Chalmers, stressed that the method can also be used to allow nanotubes to move and manipulate any other molecules with the same precision.’

Its main function will be to move biological materials, to move single molecules in solution. If you want a bottom-up kind of nano-scale assembly, or if you want to build a molecular motor, or any kind of device with just a few molecules, this process is extremely useful,’ he said.