The specific sensing and detection of lectins utilizing fluorescent sugar-substituted conducting polymers, poly(aryleneethynylene)s (PAE), is proposed. Lectins are proteins that bind to multitopic carbohydrate displays. Lectins play an important role in both bioterrorist threats as well as in early events of infectious disease transmission. The lectins that are most important for bioterrorist threats are ricin, cholera toxin, and a sugar-recognizing unit in the anthrax toxin. While the carbohydrate-recognizing lectin subunits of the toxins themselves are not toxic, they modulate the attachment and recognition of toxins to the cells. Conducting (or more precisely semiconducting) polymers of the PAE type are highly chromatic, i.e. change their color/emission depending upon the chemical surrounding they are. They have multiple attachment points for sugars and carbohydrates. Interaction of sugar-substituted PAEs with lectins should lead to a tight binding of the PAE to the protein. The binding event will change the conformation of the backbone of the PAE and thus there will be a colorimetric response, i.e. a change in color and emission of the PAE. The combination of chromicity and multitopicity make the PAEs almost ideal candidates for the sensing of lectin-based pathogens. Due to their efficient fluorescence, minute amounts of PAEs will be necessary to detect small quantities of lectins. To increase efficiency it is as well proposed to utilize PAEs immobilized on a bead to conduct the sensing of lectins. An important goal of this proposal is to determine/optimize sensitivity and specifity of the proposed sugar-substituted PAEs. However, sugar-substituted PAEs should be a very simple and powerful complementary method for the detection of the lectin-based pathogens Ricin, Cholera toxin, and the PA factor of anthrax. The sensing event should be detectable by simple inspection, or in more sophisticated cases a simple fluorescence spectrometer will be utilized.
