Using nature's nano machinery.
 

When we talk about self replication and assembly at the nano scale we can not go past nature's unique way of replicating DNA and synthesising proteins. DNA is an amazing molecule designed for data storage while the nervous system, in particular the brain, is designed for information processing.

Click to see a movie of how DNA replicates.
Nature has provided a way of manipulating the instructions provided in DNA to synthesize giant protein molecules that fold into unique shapes and perform specific functions dependant on this shape.

There are countless different proteins in the body all manufactured by special structures in the cell called ribosomes. Ribosomes attach to a giant molecule, called messenger RNA, that contains the instructions needed to assemble the protein from the 20 or so amino acids found in the body.
The animation on the right depicts the ribosome tracking along the mesenger RNA, reading the code and attaching the right amino acid to the protein chain. As the protein is formed it coils in a unique fashion depending on the sequence of amino acids that have been attached. Depending on the shape of the protein it will perform a very specific function. Click to see a simple explanation of how the code is translated in order to build the protein.
Messenger RNA can be manipulated to not only assemble amino acids into proteins but a variety of other molecules into larger structures with specific functions.

 

Using the cell's own natural machinery to assemble different molecules or components makes sense. Provided we supply the cell with the appropriate raw material and the code with which to assemble it anything is possible.
Continue with uses of carbon nanotubes in water purification