Now robotics can be even implemented at nano-scale. The nano-machines building blocks are molecules consisting essentially of an axle and a ring, or hoop, threaded over it. To prevent the hoop from slipping off the axle, bulky "stoppers" are placed at each end. These, in turn, consist of intertwined rings. This nanoscale simple system is called rotaxane (meaning "wheel axle", from ancient Greek).
To build a new type of rotaxanes, the research team around Dr. Damian Ackermann and Prof. Michael Famulok from the Life & Medical Sciences (LIMES) Institute at the University of Bonn made use of DNA, the life building block macromolecule. They exploit the principles of base-pairing of DNA double-strands for constructing sophisticated architectures at the nanoscale. The double-helix forms a very stable scaffold. Moreover, a part of one strand can be removed at any chosen position to serve as a connecting point for other components of a nanomachine. The specificity of individual strands makes DNA highly suitable offering many possibilities like Lego bricks.
The Bonn-based biochemists have created a completely new kind of rotaxane. It forms a stable mechanical unit, with a freely moving inner hoop. The axle and wheels are now available and nanoengines might also be combined with other biological systems, such as proteins.
The new rotaxanes based on mechanically interlocked double-stranded DNA have laid the foundations for developing all sorts of different nano-mechanical systems.
More information at: Damian Ackermann, Thorsten L. Schmidt, Jeffrey S. Hannam, Chandra S. Purohit, Alexander Heckel & Michael Famulok, Nature Nanotechnology 5, 436 - 442 (2010)