Selection and characterization of thioflavin T aptamers for the development of light-up probes

Aptamers are single-stranded oligonucleotides which are selected and are capable of binding certain targets tightly and specifically. Systematic Evolution of Ligands by Exponential Enrichment (SELEX) has been used to select aptamers for various targets such as proteins, metal ions, small molecules and so on. For the first time, we have used a modified SELEX technology to obtain DNA aptamers for a fluorogenic dye, thioflavin T (ThT). DNA aptamers with low micromolar dissociation constants were achieved after only 8 rounds of selection and the final minimized 33-mer aptamer showed 191-fold fluorescence enhancement in a saturated concentration. The truncated DNA aptamer showed excellent selectivity and specificity for ThT.