Synthetic 'moths' detect explosives.

• Position: Terrorist Bombs

To prevent terrorist attacks at airports, it would be helpful to detect extremely low concentrations of explosives easily and reliably. Despite the development of various sensor technologies, dogs continue to be the most efficient detectors. In the journal Angewandte Chemie, a research team has described a type of micromechanical sensor with a structure derived from the sense organs of moths.

One approach used for sensors is based on microcantilevers. These are tiny flexible devices like those used to scan surfaces with atomic force microscopes. When used in "chemical noses," they are coated with a material that specifically binds to the analytes being detected. Cantilevers can vibrate like springs. When analyte molecules are bound to a microcantilever, its mass changes along with its frequency of vibration. This alteration can be measured.

Because of their very low vapor pressure at room temperature, the highly sensitive, reliable detection of explosives remains a big challenge. In order to make microcantilevers more sensitive to the explosive trinitrotoluene (TNT), research groups led by Denis Spitzer at the French-German Research Institute of Saint Louis and Valerie Keller at the Laboratoire des Materiaux, Surfaces et Procedes pour la Catalyse in Strasbourg have taken inspiration from the highly sensitive sense organ of some types of moths.

Male silk...