Abstract: The developed long and short aptamer sequences can be used as high affinity and specificity tools to analyze the drug Dabigatran etexilate for therapeutic drug monitoring, pharmacokinetic and naturalization studies. Using the technique by performing several rounds of selection and enrichment with a randomized 60-mer DNA library, a number of specific aptamer sequences were successfully selected for Dabigatran etexilate. We evaluated the binding affinity and specificity of the generated aptamers showing dissociation constants (kd) ranging from 47-312 nM and very weak or no cross-reactivity to other analytes. Complimentary sequences labelled with a fluorophore and a quencher was used for mapping the binding region within the aptamer by monitoring the change in the fluorescence signal. A truncated sequence was used to construct a turn-on fluorescence sensor.

Abstract: An electrochemical screening method for the selection of DNA aptamers against 11-deoxycortisol (11-DCL) using gold electrode for target immobilization is described. The gold electrode is used as solid matrix instead of the beads for SELEX. The selection steps (SELEX) are performed on the 11-DC modified electrode directly as the DNA library in the first round or the enriched DNA pools in the subsequent rounds were incubated on the electrode, then the unbound DNA is washed and the bound DNA is measured directly by square wave voltammetry. Then elution of the bound DNA is performed for further use.