While the Israeli government was busy this week acknowledging its developing nanotech arsenal, UN Secretary-General Kofi Annan was in Switzerland warning of the dangers posed by military and terrorist applications of biotechnology.

"When used negligently," said the Secretary-General, "or misused deliberately, biotechnology could inflict the most profound human suffering -- ranging from the accidental release of disease agents into the environment, to intentional disease outbreaks caused by State or non-State actors."

The same could be said of nanotechnology, and anyone who can afford the equipment can now go out and buy a desktop nanofactory giving them the power to create new nanomaterials.

When we consider that, and the potential for harm, the words of one Sandia National Laboratory nanoscientist take on a sinister tone: "Design possibilities are limited only by one's imagination." (photo UN)