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Actually, many people *are* working on using biomolecules and biotechnology as crude forms of NT. For instance, DNA turns out to be a surprisingly handy structural material; cubes and other shapes have been self-assembled by synthesizing DNA segments with properly complementary nucleotide sequences.

In fact, Drexler originally thought (in the 1970s) that nanotech would *have* to be implemented through biotechnology; engineered enzymes and such.

Then the Scanning Tunnelling Microscope was invented, which points the way towards "proximal probe devices" using specialized tip-effectors (which, as Drexler covers in _Unbounding_, would probably be antibody-like molecules able to grab specific feedstock) to construct the first crude NT assemblers. These would construct better assemblers, and so on ...

It just turns out that biomolecules aren't very good engineering materials for many applications. They tend to be floppy (multiple disulfide bonds between cysteine-rich peptides notwithstanding) and vulnerable to a wide range of chemicals (although there are certainly ways to _expand_ the range in which they'll work, as heat-, salt-, pressure-, and radiationresistant bacteria illustrate; plus you could conceivably have _artificial_ amino acids that would be better suited).

Drexler recommends "diamondoid" (diamond-like, heavily tetrahedrally bonded) because it's rigid enough to avoid imprecision due to thermal and quantum effects at the nanoscale.

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= PHILLIP THORNE, <thornp2@rpi.edu>    URL: http://www.rpi.edu/~thornp2 =    

= RENSSELAER POLYTECHNIC INSTITUTE         (Always under construction!) =

= TROY, NEW YORK, USA      "It's the boundary conditions that get you." =

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• [ Next ] In reply to: Phillip Thorne