Nucleic acid aptamers targeting cell-surface proteins

Aptamers are chemical antibodies that bind to their targets with high affinity and specificity. These short stretches of nucleic acids are identified using a repetitive in vitro selection and partitioning technology called SELEX (Systematic Evolution of Ligands by EXponential enrichment). Since the emergence of this technology, many modifications and variations have been introduced to enable the selection of specific ligands, even for implausible targets. For membrane protein, the selection scheme can be chosen depending upon the availability of the system, the protein characteristics and the application required. Aptamers have been generated for a significant number of disease-associated membrane proteins and have been shown to have considerable diagnostic and therapeutic importance. In this article, we review the SELEX process used for identification of aptamers that target cell-surface proteins and recapitulate their use as therapeutic and diagnostic reagents.