In case anyone is confused by the above comment: it also appears after the previous nanodot news item, so I think the one here is a mis-post.

I always wondered what an efficient defense system would be like from well-thought out design of nano-based WMDs (weapons of mass destriction). where would our lines of defense be? maybe the last line would be a lot of synchronized nanocomputers in everyone's blood, designed to attack that offending nanobot in a random way and report any understanding of how the attacking nanobot works. how about earlier lines of defense? where would the first power to have smart dust applications draw the line?

Or maybe an attack with nanotechnology would not be biowarfare at all, but flooding or an earthquake or something of the sort…