Friday, December 29, 2006

More fabrication techniques

In the late 1990s, Tom Knight at MIT worked on something he called microbial engineering, the intentional redesign of simple (prokaryotic) bacteria, which has resulted in MIT's Biological Parts Project. The idea is to identify re-usable components that can be included in rationally designed microorganisms to perform various functions.

This idea is not without precedent: in 1978, Genentech re-engineered E. coli bacteria to produce inexpensive human insulin, vital to the survival of diabetes patients. Previously insulin had been extracted from ground-up organs of farm animals at considerably greater expense. The 1978 work did not have access to a catalog of biological parts or many of the techniques and other knowledge infrastructure that will grow up around the MIT work.

In an earlier posting I described some very interesting work being done by Christian Schafmeister, who is assembling monomer chains to create structures with specific, controllable, and reasonably rigid shapes. He is developing a collection of 15 or 20 monomers, and perhaps that number will grow over time, which can be strung together using synthetic chemistry techniques. Schafmeister has an article in this month's Scientific American.

DNA origami exploits the very selective self-stickiness of DNA. It is likely that DNA (which can be created in any desired sequence) will become a very flexible framework on which to position molecules. Proteins can also be engineered, provided we can predict how they will fold, and this should be a solvable problem if we restrict ourselves to a subset of well-understood proteins. Many proteins like to cling to DNA at very specific locations. A combined approach using a DNA scaffolding, with attached proteins to provide local functionality, could yield very interesting results.

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