How silkmoths could defeat terrorism and drug smuggling (BBC)

Christopher Mims

Inspired by antennae that can detect a female moth miles away, scientists have created the world's most sensitive electronic nose for explosives.

Forget surveillance cameras – what if our world were filled with always-on electronic noses tuned to detect all manner of contraband at minute concentrations? Drugs, explosives, air pollution, all of them could be monitored continuously, creating a "smell portrait" of the entire planet, and making it virtually impossible to conceal the trace odour of many legal and illegal substances.

That's the vision of scientists who work on electronic noses, and now, thanks to the silkmoth, the world's most sensitive electronic nose for explosives was recently demonstrated in the lab. One thousand times more sensitive than comparable devices, it consists of a tiny, vibrating cantilever coated in a forest of titanium dioxide nanotubes that were inspired by similar structures on the antennae of silkmoths.

Male silkmoths can detect females at distances of 5-10 kilometres (3-6 miles), and can register as few as one or two molecules of their pheromone scent. Five years ago, Denis Spitzer of the defence-focused Institut Franco-Allemand de Recherches de Saint-Louis heard about the super-sensitive feats of the silkmoth and wondered whether this could be reproduced by a machine.

One of the keys to the moth's performance is that its antennae are covered with a carpet of tiny sensilla, or microscopic fibres. These sensilla give the moth's detection apparatus much greater surface area than they would otherwise have, which is important for detecting very small concentrations of volatile compounds. These sensilla inspired Spitzer to upgrade an existing solution to "smelling" compounds with silicon.
***
more: http://www.bbc.com/future/story/20120828-smelling-lessons-from-silkmoths
original pub from APRIL: http://onlinelibrary.wiley.com/doi/10.1002/anie.201108251/abstract