Home > Explosives Detection > Technology > Molecular Spectroscopy > Amplifying Fluorescence Polymers (AFP)

Research at Massachusetts Institute of Technology under Dr. Timothy Swager has led to chemical detection devices based on amplified fluorescence quenching of solid-state conjugated polymer films. The sensor consists of a glass capillary tube whose interior is coated with a polymer film comprised of a conjugated backbone with pentiptycene groups. In operation, the AFP polymer is excited to a fluorescent state using a light source external to the capillary tube. An air pump is then used to draw the sample through the capillary; compounds containing nitroaromatic groups (TNT, RDX, etc.) bind to the polymer, causing fluorescence to be quenched. The change in fluorescence is read as a change in response at a photometer positioned axially to the capillary. Because the polymer chains are electronically conjugated, binding at any point along the polymer chain results in complete quenching of all sites on the polymer. The effective amplification in response by this technique over monomeric quenching is estimated to be from 100X to 1000X.