Nano–Assembly

Researchers from the ETH Zurich have taken an important step towards creating an assembly line at the molecular level. The molecular assembly line features all the elements of a conventional production line– a mobile assembly carrier, an assembly object, assembly components attached at various assembly stations and a motor (including fuel) for the assembly carrier to transport the object from one assembly station to the next.

Researchers used microtubules as assembly carriers. Microtubules are string–like protein polymers which, together with kinesin, transport cargo around the cells. With its mobile heads, kinesin binds to the microtubules and propels them forward along the surface of the device. This propulsion is further supported by the current generated by the fluid being pumped into the canal system with the main canal just 30 micrometres wide, that is, three times thinner than a human hair. Five inflows and outflows direct the current in the main canal and divide it into strictly separated segments: a loading area from where the assembly carriers depart and two assembly stations and two end stations to where the cargo is delivered. These inflows and outflows lead to and from the canal at right angles.

Researchers can add objects to the system through lines that supply the assembly segments. In their most recent work, they tested the system using NeutrAvidin, the first molecule that binds to the nanoshuttle. A second component, a single short strand of DNA then binds to the NeutrAvidin and creates a small molecular complex.