aptamersnucleic
Aptamers are short single-stranded DNA or RNA molecules that fold into defined three-dimensional structures, enabling high-affinity and high-specificity binding to a wide range of targets, from small molecules to proteins, cells, and whole organisms. They are generated from large libraries of randomized sequences through in vitro selection methods, most commonly SELEX (systematic evolution of ligands by exponential enrichment). In SELEX, successive rounds of binding, separation of bound from unbound sequences, and amplification enrich aptamers with the desired binding properties. Variants include cell-SELEX, which selects against cell-surface targets, and capillary electrophoresis SELEX, which can increase selection stringency and speed. RNA aptamers can be reverse-transcribed to DNA for amplification, while DNA aptamers are typically more chemically stable.
Chemistry and optimization: Aptamers may be composed of DNA or RNA and are often endowed with chemically
Applications: In medicine, aptamers have been explored as therapeutics, including anti-VEGF agents such as pegylated Macugen
Advantages and limitations: Aptamers offer synthetic production, low immunogenicity, and easy modification, with the potential for