DNA Aptamer Development for Detection of Atrazine and Protective Antigen Toxin Using Fluorescence Polarization

Aptamers are becoming a viable alternative to antibodies as bio-recognition elements in analytical, diagnostic and therapeutic applications. In this research two aptamers were developed using capillary electrophoresis systematic evolution of ligands by exponential enrichment (CE-SELEX). These aptamers were selected from and artificial library of single stranded deoxyribonucleic acid (ssDNA) with 40 randomized nucleotides flanked by two priming sites with a diversity of 1015 different sequences.The first target employed in this study was the extensively used herbicide, atrazine, for which and aptamer with dissociation constant of 890 nM was selected.The second target was Protective antigen toxin from the gram positive spore forming bacteria Bacillus anthracis for which an aptamer with a dissociation constant of 112 nM was selected from the library.These two aptamers were used to construct a bioassay based on fluorescence polarization, for the successful detection of their respective targets in spiked samples under different conditions