Generation of bivalent aptamers with high affinity and selectivity for detection of viruses and bacteria from environmental samples

Better methodologies for the rapid detection of pathogenic bacteria and viruses are needed. A particular problem with current antibody-based assays is cross-reactivity with similar, but harmless, species. Radiation Monitoring Devices, Inc. proposes developing nucleic acid-based affinity reagents (aptamers) against botulinum neurotoxin, as well as against a model pathogenic virus (VSV) and spore (Bacillus subtilis). Aptamers displaying fast binding rates (kon) will be selected to increase the speed of the assay. A novel approach using bivalent, bispecific aptamers will be utilized to achieve binding affinities at least equal to that of typical antibodies. The aptamer selectivity will be enhanced by employing counterselection procedures whereby aptamers binding related species are deselected. Finally, the aptamers will be applied to an ELISA-like protocol and their performance directly compared to antibodies. Anticipated Benefits/Commercial Application A more rapid, sensitive, and selective assay for the detection of bacteria and viruses will have widespread applications in homeland security, the military, healthcare, and food safety. The assay could be used to screen ports of entry, public places of interest, and military sites for evidence of biological threat agents. Likewise, the assay could be used in a laboratory or clinical setting to rapidly diagnose infectious diseases.