earticle

영어

In this study, the five different aptamers (to Oxytetracyclin, Tetracyclin, Ibuprofen, Diclofenac, and b-estradiol) having different affinity ratios were used, and the order in the sensitivity of target detection was found to be well correlated with its affinity ratio. An affinity ratio, the affinity of the aptamer to targets divided by the affinity to umAuNPs (KdAuNP/KdTarget), was found to be an important factor determining the sensitivity in the competitive interactions among aptamers, targets, and unmodified gold nanoparticles (umAuNPs) [1]. This working principle was primarily confirmed by using a tetracycline binding aptamer showing different affinities to its three derivatives, tetracycline, oxytetracycline, and doxycycline [2]. The color change of the mixture containing umAuNPs, targets, and the tetracyclin binding aptamers (TBAs) was found to be proportional to the affinity ratio of TBA to each of three target compounds. In addition, by implementing this principle established, the sensitivity of ibuprofen detection could be enhanced simply by increasing the ratio of affinity, i.e., reducing the ibuprofen binding aptamer’ affinity to umAuNPs by using bis (p-sulfonatophenyl) phenylphosphine as an AuNP-capping ligand, instead of using the citrate. A clear color change was resulted even at a 20-fold less amount of ibuprofen. Finally, this working principle has been also strongly supported and confirmed by adsorption-equilibrium based mathematical model simulation.