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A biotin:streptavidin alternative for non-radioactive hybridization assays—Digoxigenin

Modification Highlight: Learn about Digoxigenin—a modification suitable for use as an alternative to biotin/streptavidin for non-radioactive hybridization applications.

Quick facts:

Availability: DNA or RNA
Location: 5′ or 3′
Scales: 100 nmol to large scale
Purification: HPLC required
IDT Ordering Symbol: /5DigN/ or /3Dig_N/

A sensitive fluorescent assay

CC_Mod highlight_Digoxigenin
Figure 1. Chemical structure of digoxigenin (DIG).

Digoxigenin (DIG) is a small hapten that can be easily conjugated via an NHS ester reaction to oligonucleotides on their 5′ or 3′ terminus. DIG can be used together with a DIG antibody as an alternative to the biotin/streptavidin system, or could be used simultaneously when a multiplexed assay is needed. This modification is also commonly used in non-radioactive immunoassays, northern/Southern blot analysis, and in situ hybridization applications.

DIG-labeled oligonucleotides are monitored with anti-DIG antibodies. The interaction between DIG and anti-DIG& antibodies is very strong, thus providing a sensitive assay that can be observed directly with fluorescence. In such experiments, the antibodies are fluorescently tagged. Alternatively, the interaction can be detected indirectly; for example, using an enzyme-linked immunoassay.

To order, select DIG from the 5’ or 3’ Mods tab on the oligo order page. Note that DIG-modified oligos require HPLC purification.

See what other modifications are available from IDT. You can find a list of standard modifications we make to oligonucleotides on the Modifications page of our online catalog. And if you don’t find what you are looking for, just send us a request. We often synthesize special, non-catalog requests. Contact us at

Published Jun 15, 2012
Revised/updated Sep 30, 2015