Abstract
Aptamers are rare functional nucleic acid ligands that bind with high affinity and specificity to their target ligands. Selected aptamers have been shown to inhibit the functions of their cognate targets both in vitro and in vivo. As a consequence, the first aptamer-based drug to treat age-related macular degeneration has been developed. On another front, aptamers have also successfully shown potential use in diagnostics and imaging technology. The next wave of aptamer applications involves the development of ligand-induced aptamers. These aptamers rely on the principles commonly observed in many ribonucleic acid (RNA)-ligand interactions. In the present review, we describe the various strategies for designing ligand-induced aptamers and their applications, including monitoring different ligands, regulating gene expression and expanding microarray analyses.