Fingerprints of fear

Could safety concerns about nanotechnology derail its promise in medicine?

The trouble began with a spate of suspicious handprints in the early 2000s. Chalky, hand-shaped defects had started to show up on sheets of metal roofing soon after they were installed.

Clearly something on the hands of the roofing contractors was damaging the painted surface of the metal, but what exactly? Researchers at Bluescope Steel, the manufacturers of the roofing, were charged with solving the intriguing case.

After some careful investigation work,