Aptamer-Based Strategies to Address Challenges in COVID-19 Diagnosis and Treatments

Figure 1

Selection of aptamers using the SELEX method: (a) the SELEX involves an iterative selection of ssDNA or RNA aptamers from a randomized oligonucleotide library where the selection starts by immobilizing the target of interest to beads, (b) the immobilized target of interest is then incubated with a randomized oligonucleotide library, (c) following incubation, the unbound oligonucleotides are separated from the bound aptamers, (d) the bound aptamers are then eluted from the immobilized targets and (e) amplified using PCR to create a new enriched selection pool, (f) the enriched pool serves as a starting library for the next SELEX cycle and the cycle is repeated for 6–13 rounds to achieve desired binding affinity, and (g) once the binding affinity is achieved, the aptamers of the last round are cloned and sequenced.