Nanotubes 101
Nanotubes are very small. They have a "honeycomb structure" and are "grown" to the specific dimensions needed for what kind of molecule they want to detect. They are porous at the angstrom level.The angstrom, also known as the angstrom unit, is a measure of displacement equal to 0.0000000001 meter (10-10 m). It is sometimes used to express wavelengths of visible light, ultraviolet (UV) light, X rays, and gamma rays.
When the tube finds a match, it send out an electric signal. You only need 2 wires for an elecric signal.
This is the simple version, but you should get the idea.