There are reasons very little work is going into it - the concept makes very little sense compared to manipulating biological systems or making systems that work similar to biological systems. See http://www.sciencemag.org/content/347/6227/1221.short or this previous post of mine: http://lesswrong.com/lw/hs5/for_fai_is_molecular_nanotechnology_putting_our/97rl
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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