In the past two years, Mexican nanotechnology researchers have been subject to a spate of bombings and bomb threats. In the worst of the attacks, two researchers were injured. Police say that if the explosive had gone off properly, a whole building could have collapsed.

Meanwhile, Italian, Swiss and German authorities this summer arrested members of related groups whom they think were responsible for trying to bomb IBM’s European flagship nanotechnology lab, and for shooting in the kneecap a nuclear engineer at a firm engaged in nanotechnology and biotechnology research. France has also seen angry protests and attempts to shut down public debates on nanotechnology.

Some policy-makers in Europe and elsewhere have long feared that research on nanotechnology could spark a public backlash — similar to those seen against genetically modified (GM) crops and animal experimentation. Has it arrived — and in a violent fashion?

As the Feature on page 576 highlights, public awareness of nanotechnology remains low and fears of widespread opposition are premature. But how it may pan out is hard to predict. Sympathy for animal-rights violence was always thin on the ground even though opposition to vivisection was quite broad: conversely, few members of the public have ever participated in anti-GM vandalism, yet there is a de facto European moratorium that has all but frozen the industry on the continent.

The more outlandish claims made for nanotechnology stir fear among the public. Opponents know this, so whereas scientists and officials want to talk about environmental and exposure risks, consumer awareness and product regulation, the extremists and some mainstream non-governmental organizations focus on nanometre-scale sensors, cyborgs and swarms of self-replicating robots.

Nanotechnology advocates have an important role here, and one that could help to determine how public awareness of nanotechnology develops. They should continue to work to make public debate informed and accurate, and do more to monitor and test the possible toxicity of novel products. And they should avoid hype. If they paint a true picture of the state of the science, then the distorted version drawn by the extremists will have a greater chance of being recognized as such.