2009 - Timothy M. Swager
Polymer Electronics For Chemical And Biological Sensors
This lecture will describe the conceptual design and optimization of chemical/biological sensors based upon conjugated polymers (CPs) and carbon nanotubes (CNTs). The ability of a CP to produce amplification in a fluorescence- or resistance-based chemosensor stems from its ability to transport optical excitations or electrical charge, respectively, over large distances. These transport properties provide the increased sensitivity and versatility of CPs and CNTs over small-molecule chemosensors. By adding new functional diversity to CPs and CNTs chemoresistive properties have been realized. In a fluorescence sensors, the migration of an optical excitation increases the probability of an encounter with an occupied binding site. We originally demonstrated this scheme making use of analyte induced quenching and have also demonstrated how local reductions in the polymers bandgap produce wavelength shifts in emission. To impart recognition to our polymers we have made use of a variety of molecular recognition schemes, assemblies, and reactions. Recent applications of amplifying polymers in biosensory schemes will be discussed.
A number of different methods can be used to impart analyte selectivity to electronic polymer sensors. These involve designed receptors, modifications to the energy levels of the polymers, and coupling to other key reactions. I will detail some of our latest results in these directions.