Figure 1.

Systematic evolution of ligands by exponential enrichment (SELEX), for the generation of either single-stranded DNA or RNA oligonucleotides that bind to a target ligand. SELEX starts with the incubation of a nucleic acid library with the target protein. Unbound aptamers are washed off and protein-bound aptamers are eluted and amplified to create the library for the next round of selection. After iterative selection rounds, potential target-specific sequences are enriched and dominate the population of aptamers.