The Combinatorial Libraries of Oligonucleotides

Summary: To distinguish one member from another in the pool of oligos, a tagging system has been created.

Over the last ten years, there has been significant improvement in the development of compound libraries for the discovery of molecules with new binding properties. The basic premise is to ultimately shorten the effort and time associated with the search of drugs leads by creating a large combination of molecules that are tested against a certain target for a specified activity. However, there is a problem with this technique as that there lacks a proper strategy to determine the identity of the active molecules from the mess of the original pool. To solve this, researchers have developed a system that utilizes either tagged or untagged labels.

Tagging Methodology

The use of these tags have established a beneficial relationship between each single member of the library and the tags itself with gives it a unique identity. Even through the process of synthetic DNA playing a role in presenting itself as a different member, these powerful tag technologies have become important tools to separate themselves from the pack. Additionally, researchers have discovered flexible and versatile ways to apply these tags to multiple areas of molecular biology, therefore expanding the real of possibility.


There is a certain strategy that makes use of modified oligos that´s called Selective Enhancement of Ligands by Exponential Enrichment, or SELEX for short. What this technique does is executes multiple cycles of selection and amplification, which results in competition between the molecules that are deemed suitable from the huge population in the pool. Essentially, the pool is separated by individual members to appropriate them to a given task (usually a binding or catalytic task).

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