Capture-SELEX for aptamer selection: A short review

The emerging aptamer, developed through the systematic evolution of ligands by exponential enrichment (SELEX) process, has revolutionized and facilitated the discoveries in basic research. Among all SELEX technology, Capture-SELEX is a variant of the in vitro selection process, which is suitable for isolating aptamers against small molecules. Capture-SELEX library was developed to enable the immobilization of the oligonucleotides instead of the target molecules during the aptamer selection process. The review provides an update on the recent-advances in this new screening method with particular emphasis on key points of capture protocol and its applications. The limitations and the prospects of the Capture-SELEX are also discussed. We hope that present review will inspire more researchers to understand the selection problems from the perspective of Capture-SELEX. Moreover, it will open new pave to improve the efficiency and success of screening to meet the growing demand for aptasensor discovery in small molecules.

An ssDNA library immobilized SELEX technique for selection of an aptamer against ractopamine

An improved SELEX technique was developed for selecting aptamers against ractopamine (RAC) by immobilizing ssDNA library on the magnetic beads. After sixteen selection rounds, a highly enriched ssDNA pool was sequenced and nine families were grouped according to their homology and secondary structures analysis. One representative aptamer candidate from each family was picked out for binding affinity identification by graphene oxide (GO) adsorption platform. The aptamer RAC-6 was demonstrated as the optimal aptamer with high specificity and dissociation constant (K_d) value of 54.22 ± 8.02 nM. To prove the potential application of aptamer RAC-6 in the quantitative determination of RAC, a fluorescent bioassay with aptamer RAC-6 was developed. The linear range for RAC was from 0.10 ng/mL to 100 ng/mL and the limit of detection was as low as 0.04 ng/mL. Furthermore, the method was validated for the analysis of RAC spiked real samples, and the recoveries were between 82.57% and 104.65%.