Selection and Characterization of Malachite Green Aptamers for the Development of Light–up Probes

Abstract The light‐up fluorogenic dyes exhibit excellent behavior that autofluorescence is very low but substantially increases when interacting with their ligands. Aptamers are single‐stranded oligonucleotides which are selected and are capable of binding certain targets tightly and specifically. Developing fluoreogenic dye‐aptamer light‐up fluoromodules will greatly prompt the development of label‐free probes for various detection purposes. A fluoregenic triphenylmethane dye, malachite green (MG) was found to have low quantum yield in fluid solutions, but restricting vibration was known to induce fluorescence enhancement. We used the modified in vitro selection method which is based on the target‐induced release of aptamers as the separation technique to isolate DNA aptamers for MG. 8 rounds of selection process was carried out, and the fluorescent intensity of MG was dramatically enhanced in the presence of a minimized 26‐mer DNA aptamer with low micromolar affinity. The MG‐aptamer pair could potentially be used as a novel light‐up fluorescent probe for various applications.