What are aptamers?
Introduction and Application of Aptamer
Aptamers are essentially short RNA or single-stranded DNA oligonucleotides (usually 20–80 nucleotides with 6–30 kDa molecular weights) that can fold into unique three-dimensional conformations. Similar to conformational recognition that mediates antibody-antigen recognition and complex formation, aptamers bind to their cognate targets using high-specificity and -affinity through van der Waals forces, hydrogen bonding, electrostatic interactions, stacking of flat moieties, and shape complementarity, with dissociation constants (Kd) usually ranging from pico- to nanomolar. Thus, aptamers are also referred to as “chemical antibodies” and are functionally used as antagonists, agonists, or targeting ligands.
Figure 1 Schematic diagram of aptamer conformational recognition of targets to form an aptamer-target complex.
The specificity of aptamers toward target ligands makes them an ideal tool for diagnostics and therapeutics. Aptamers have also been extensively used in analytical applications.