The OP asks reasonable technical questions about medical nanorobots. I'm not going to defend Kurzweil, but some less-sloppy thinkers have written about this kin

The OP asks reasonable technical questions about medical nanorobots. I'm not going to defend Kurzweil, but some less-sloppy thinkers have written about this kind of stuff, like Merkle, Freitas, and Drexler. E.g. http://www.merkle.com/cryo/techFeas.html http://www.merkle.com/cryo/techFeas.html http://www.nanomedicine.com/NMIIA/15.3.6.5.htm http://www.nanomedicine.com/NMIIA/15.3.6.5.htm They do tackle questions like how do you power these things; I wish he'd read and criticize them instead. A 7-micron-long medical nanorobot sounds pretty damned big to me, btw -- in _Nanosystems_ Drexler fits a 32-bit CPU in a 400nm cube, less than 1/300 of the volume if we're talking about a 1-micron-radius cylinder.