Deliberate abuse, the misuse of a technology by some small group or nation to cause great harm, is best prevented by measures based on a clear understanding of that technology. Nanotechnology could, in the future, be used to rapidly identify and block attacks. Replicating manufacturing systems could rapidly churn out the needed defenses in huge quantities. Such systems are best developed by continuing a vigorous program of research and development, which provides a clear understanding of both the potential threats and the countermeasures available. Besides deliberate attacks, the other concern is that a self-replicating molecular machine could replicate unchecked, converting most of the biosphere into copies of itself.
Living systems are wonderfully adaptable and can survive in a complex natural environment.
Instead, nanotechnology proposes to build molecular machine systems that are similar to small versions of what you might find in today's modern factories. Robotic arms shrunk to submicron size should be able to pick up and assemble molecular parts like their large cousins in factories around the world pick up and assemble nuts and bolts. We automatically assume that nanotechnological replicating systems will be similar when, in fact, nothing could be further from the truth. The machines people make bear little resemblance to living systems, and molecular manufacturing systems are likely to be just as dissimilar. Zyvex is developing positional assembly systems at the micron, sub-micron and molecular scale.