SolidState: Thank you for your excellent input on the current state of the art and where some of it is leading. However, to dismiss enmass-parallel mechanosynthesis is very short-sighted. There is a place for both the types of systems you mention, and, the mechanosynthesis (not loose nanobots floating around, that is in theory possible but that is not where the real value is)-based atomic-precision assembly.
We must model the micro-world like we model the macro-world. There are certain aspects such as stiction and certain surface features that are different "down there", and gravity is not as large a concern as it is "up here", but, at the same time, when people dismiss the work of Drexler and others by claiming he is simply scaling down macroscopic machines to the molecular level and try to dismiss that, they are not looking at the whole picture.
The mechanics and physics down there are basically the same as the ones up here (macro-level) or else the entire universe would fall apart.
Bioorganisms and biological systems use wet-ware engineering and water-solvents because it is on the lower entropy scale and is cheaper energy wise. This in no way precludes other methods.
Let me give you some examples:
There is a man named Richard Jones from England who makes the claims that only "soft machines" based on biology can be built. I would counter this in two ways: One, to show that this is not the case, and two, to show that even using wetware, we can bootstrap dryware nanotechnology and while it would take more time, there is already a basis with protein engineering, viral and biological engineering, and other things, which you sortof pointed out.
For example: Nested carbon nanotubes have already been shown to have very low friction and they work as efficient bearings, refuting the claim by Jones that non-biological molecular bearings would have high friction and not work.
A eutactic system, in which the trajectories and orientations of all atoms in the system are precisely controlled and directed to and from reaction sites at high speed, will be intrinsically more efficient than a system that relies on the random motion of molecules for transport and assembly processes. On a more primitive level, this is the principle behind catalysts, which are used to accelerate industrial chemical reactions by guiding molecules together in favorable orientations.
We can construct these sorts of structures using a molecular nano assembler system based on the INCA: Inter Nodal Connector Architecture: US Patent here:
https://www.google.com/patents/US686924 ... CB0Q6AEwAA" target="_blank
" A universally compliant and restorative internodal connector architecture system wherein a plurality of nodal members are interconnected by a spring and strut assembly in a manner that permits manual or actuated relocation of the nodal spacial definition using standard modules."
This is a collection of springs, nodes, and struts that is based on the natural curvature we see in nature, in the carbon buckyball fullerene molecule. It can be scaled up from the molecular to the macroscopic level. And, it can be built with conventional polymers, metals, and other structures, to make macroscopic collapsible structures that have the strength of solid materials.
With this we can make folding "nano to macro" origami based structures that can be used to produce such things as a torus toroid that spin, for spinning to make artificial gravity habitats in space (yes, you read right), where we have all the vacuum you can ever desire, SolidState, for all of the deposition mechanisms you could ever desire.
Here is a good article that describes some of what I am discussing:
http://www.zyvex.com/nanotech/impossible.html" target="_blank
http://www.zyvex.com/nanotech/errorRates.html" target="_blank
There is no physical or scientific law against constructing molecular mechanosynthesis, aka, positional chemistry devices. As time goes on and we get closer and closer to this, more and more organizations, universities, and companies will see the value. Think about it, can you imagine you and the guys in your field having the ability to position molecules directly, and do so in a repetive fashion? Even Richard Feynman himself spoke of it back in `59.
Angela Belcher at MIT has a lab where they used viruses to grow metal structures for batteries and circuits. If you can grow a complicated structure such as a battery or a computer, you can make simpler structures like knife blades, with atomic-precision, eventually.