Study of thiazole orange in aptamer-based dye-displacement assays

We screened a series of RNA and DNA aptamers for their ability to serve in the dye displacement assays in which analytes compete with TO dye. We conclude that, while the performance of the TO dye displacement approach is not always predictable, it is still a simple and sensitive assay to detect binding between RNA aptamers and small molecules. In particular, we describe efficient assays for tobramycin and theophylline, with up to 90% displacement of TO observed, and we describe the first aptameric assay for cAMP. Figure An RNA or DNA aptamer against a molecule (circle) binds TO dye, resulting in a fluorescent complex. Presence of free molecule in solution results in the displacement of TO from the complex and a reduction in fluorescence Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.