US Patent 7824619 - Molecular sensors for explosives

http://www.freepatentsonline.com/7824619.html

Conventional chemical sensors have been unable to compete with the sense of smell of trained animals such as dogs but this patent proposes a nanosensor which may be competitive in detecting minute amount of air-borne molecules of explosive materials. Claim 1 reads:

1. A sensor for detecting the presence of a target analyte comprising a nitro-containing explosive molecule, the sensor comprising:

a support substrate;

a pair of electrodes comprising a first electrode and a second electrode, wherein said first and second electrodes comprise the same or different materials, and wherein at least one of said first and second electrodes is at the substrate;

an electron donor molecule capable of forming an electron donor-acceptor complex with the nitro-containing explosive molecule, wherein the electron donor molecule is chemically bonded to said first electrode and to said second electrode, thereby forming a nanojunction between said first and second electrodes;

a means for detecting a change in the electrical resistance or in the capacitance of the sensor when the electron donor molecule forms an electron donor-acceptor complex with the nitro-containing explosive molecule, wherein said means for detecting a change in the electrical resistance or in the capacitance of the sensor is electrically connected to said pair of electrodes, the sensor thereby detecting the presence of the nitro-containing explosive molecule.