DNA SELEX: Insights and Strategies

Review Article

Abstract

Aptamers are synthetic nucleic acid ligands used in therapeutic and diagnostic applications. They bind targets with high specificity and sensitivity and can be selected against various targets. Compared with antibodies, aptamers offer various advantages. This includes low-cost chemical synthesis without the need for animals or cell culture and minimal batch-to-batch variability. They undergo straightforward chemical modification, maintain long-term stability at room temperature, and can be selected against targets that are poorly immunogenic or otherwise difficult to generate antibodies against. The main limitation of aptamers is their sensitivity to nucleases. This can be addressed through chemically modified, nuclease-resistant variants. The other issue for cross-reactivity in complex biological samples is mitigated through counter-selection and in vivo SELEX strategies. Aptamers are identified through SELEX, an iterative enrichment process using large DNA or RNA libraries. This review outlines the essential steps involved in DNA SELEX. It synthesizes recent strategic and conceptual advancements from the past few years, including nuclease-assisted kinetic selection, Motif-SELEX, functional-group-guided small-molecule aptamer development, and aptamer-assisted dual-site SELEX. The goal is to distill practical design principles for researchers who are either entering the field or seeking to advance their work in this area.