Photo-cleavable spacer

Product spotlight: This modification can be cleaved by a specific wavelength of UV light, fragmenting an oligo or releasing a terminal modification, such as a fluorophore.

Apr 26, 2012

Revised/updated Nov 1, 2017

Quick facts:

Availability: DNA or RNA
Scales: 100 nmol to large scale
Purification: HPLC required
Symbol for ordering: 5’ mod: /SSpPC/, internal mod: /iSpPC/


Figure 1. Photo-cleavable spacer.

UV light cleavage

Photo-cleavable (PC) modifications contain a photolabile functional group that is cleavable by UV light of specific wavelength (300–350 nm). The PC Spacer is a 10-atom linker arm that can only be cleaved when exposed to UV light within the appropriate spectral range. The resulting oligo will have a 5’ phosphate group that is available for subsequent ligase reactions.

PC Spacers can be placed between DNA bases or between an oligo and a terminal modification such as a fluorophore. IDT also offers 5’ PC Biotin (/5PCBio/), which allows for post-binding release and the design of controlled capture-and-release assays.

To order, select PC Spacer or PC Biotin from the 5’ Mods or Internal Mods tab on the oligo order page. Note that this modification requires HPLC purification.

Modifications to facilitate your research

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