Meh, another buzzword. I actually don't think we'll see nanosurgery for a very long time, and we should be able to solve the problem of "death" many generations of tech before we can do nano-surgery.
Think about what you actually need to do this. You need a small robot, composed of non-biological parts at the nanoscale. Presumably, this would be diamondoid components such as motors, gears, bearings, etc as well as internal power storage, propulsion, sensors, and so on. The reason for non-biological parts is that biological parts are too floppy and unpredictable and are too difficult to rationally engineer into a working machine.
Anyways, this machine is very precisely made, probably manufactured in a perfect vacuum at low temperatures. Putting it into a dirty liquid environment will require many generations of engineering past the first generation of nanomachinery that can only function in a perfect vacuum at low temperatures. And it has to deal with power and communication issues.
Now, how does this machine actually repair anything? Perhaps it can clean up plaques in the arteries, but how does it fix the faulty DNA in damaged skin cells that cause the skin to sag with age? How does it enter a living cell without damaging it? How does it operate inside a living cell without getting shoved around away from where it needs to be? How do it's sensors work in such a chaotic environment?
I'm not saying it can't be done. In fact, I am pretty sure it can be done. I'm saying that this is a VERY VERY hard engineering problem, one that would require inconceivable amounts of effort. Using modern techniques this problem may in fact be so complex to solve that even if we had the information about biology and the nanoscale needed to even start on this project, it might be infeasible with modern resources.
If you have these machines, you have a machine that can create other nanomachines, with atomically precise components. Your machine probably needs a vacuum and low temperatures, as before. Well, that machine can probably make variants of itself that are far simpler to design than a biologically compatible repair robot. Say a variant that instead of performing additive manufacturing at the nanoscale, it can tear down an existing object at the nanoscale and inform the control machinery about the pattern it finds.
Anyways, long story short : with a lot less effort, the same technology needed for nanosurgery to be possible could deconstruct preserved human brains and build computers powerful enough to simulate these brains accurately and at high speed. This solves the problem of "death" quite neatly : rather than trying to patch up your decaying mass of biological tissue with nanosurgery, you get yourself preserved and converted into a computer simulation that does not decay at all.
I think you may have misunderstood me. By "nanosurgery" I meant not solely Drexlerian medical nanobots (though I wasn't ruling them out). Any drug whose design deliberately and intentionally causes specific, deliberate, and intentional changes to cell-level and molecular-level components of the human body, deliberately and consciously designed with a deep knowledge of the protein structures and cellular metabolic pathways involved, qualifies as nanosurgery, by my definition.
I contrast nanosurgery: deliberate, intentional action controlling the ac...
From Gene Expression by Razib Khan who some of you may also know from the old gnxp site or perhaps from his BHTV debate with Eliezer.
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