Nanotech seems to be smaller risk than AI or biotech, but it advanced form has many ways of omnicide. Nanotech will be probably created after strong biotech, but short before strong AI (or by AI), so the period of vulnerability is rather short. Anyway nanotech has different stages it its future development, mostly dependent on its level of miniaturisation and ability to replicate. To control it in the future will be build some kind of protection shield which may have its own failure modes.
Some integration between bio and nanotech has already started in the form of DNA-origami. So may be first nanobots will be bionanobots, like upgraded version of E.coli.
Pdf is here: http://immortality-roadmap.com/nanorisk.pdf
In the beginning of 21 century some concerns were raised about saefty of strong nanotech - Bill Joy, Freitas. In the same time US and Russia addopted national nanotechnology iniciatives in which original meaning of the word "nano" were replaced from nanorobotics to colloid solutions and fullerens. But a question of safety existed and in Russia was created a commission for estimation of safety of nanoprticles in 2011 - http://www.rg.ru/2011/10/12/nano.html I think that it is reflection of earlier concerns about nanosafety adapted to new meaning o
Nanotech seems to be smaller risk than AI or biotech, but it advanced form has many ways of omnicide. Nanotech will be probably created after strong biotech, but short before strong AI (or by AI), so the period of vulnerability is rather short. Anyway nanotech has different stages it its future development, mostly dependent on its level of miniaturisation and ability to replicate. To control it in the future will be build some kind of protection shield which may have its own failure modes.
The main reading about the risk is Freitas's article "Some limits to global ecophagy by biovorous nanoreplicators" and "Nanoshield".
Some integration between bio and nanotech has already started in the form of DNA-origami. So may be first nanobots will be bionanobots, like upgraded version of E.coli.
Pdf is here: http://immortality-roadmap.com/nanorisk.pdf