NANOTECH == BIOTECH
I present here a short argument to explain the strong statement made in this node title. Some of the steps might be a little tenuous, and it's possible that some of them are plain wrong. If this is the case, please /msg me and tell me why. Yes, I am a biologist. :)
- Nanotechnology refers to devices smaller than 10-6meters in size. (µm)
This is an axiom, a base assumption. A micrometer is still very small (a thousandth of a millimeter) - but it is not nano-tech.
- Nanomachines are made of inorganic substances
This might seem like an odd assertion - there are carbon compounds that would be suitable, and yet not 'biological'. This is a fuzzy division of the set of chemicals but a valid one. There are organic semiconductors and light-emitting polymers which are distinct from the types of chemicals life uses.
- Construction must be bottom-up
I'm (somewhat belatedly) reading Engines of Creation as I write this, and Drexler explains quite clearly why nanoscale devices are best constructed by other devices at the same scale. It would be economically infeasible to construct each device individually, top-down.
- Self-assembly requires available materials
Life uses iron more often than vanadium because it's much more readily available. A nanomachine could not be made of exotic atom types without 'starving'. Either you make them in the lab before sending them out or they must be made from the same chemicals as biological structures.
- Nanomachines would be eaten
Following on from the previous step, these machines would be a rich source of food for bio-nanomachines. If they were inedible, they would not be made of available materials - and if they are made of available materials, they will be edible.
- Diamond cannot be made at RTP by enzymes
While carbon nanotubes are quite easy to make (candles can make buckminsterfullerene) - diamond is not. The energetics of the process are not chemically possible. Artificial diamonds are made very nicely in large machines use enormous pressure and solid-state chemistry.
In summary, my bones are made of rock; nettles have silica spines; some bacteria can live in crystals. Life has been, and always will be, intertwined with the inorganic world and imagining that it is possible to separate the two is sci-fi, not science.