US Patent 7112816 - Molecular Sensor Using Functionalized Carbon Nanotube

http://www.freepatentsonline.com/7112816.pdf

Carbon nanotubes can be used as resonating cantilevers if fixed at one end. By chemical functionalization the nanotubes can be made responsive to specific molecules which may be detected via alteration of the nanotubes resonant characteristics. This patent presents some broad claims to this type of sensor. Claim 22 is representative.

22. A carbon nanotube sensor for detection of a small particle or molecule, said sensor comprising: a gate; a source and a drain positioned on said gate; a carbon nanotube extending from one of said source and said drain and being grown from a catalytic material deposited on one of said source and said drain; a functional receptor disposed at an end of said carbon nanotube such that said carbon nanotube is receptive to at least one of the small particle and the molecule; wherein said carbon nanotube resonates at a first resonance frequency when said functional receptor at said end of said carbon nanotube is free of the small particle and the molecule, and said carbon nanotube resonates at a second resonance frequency that is different from said first resonance frequency when at least one of the small particle and the molecule is associated with said functional receptor at said end of said carbon nanotube.