Cholesteryl Oligo Modification

Cholesteryl

Cholesterol and cholesteryl modifiers are used to facilitate the permeation of cell membranes. These oligos can be used in conjunction with lipofectin, or liposome incorporation of the oligo.

The cholesterol type modifications are available to tag either the 5' or 3' end of the oligo. Cholesterol is available for labeling the 3' end of oligo and cholesteryl is available for labeling the 5' end. As with the 3' modifier, labeling occurs during the course of synthesis. The 5' cholesteryl modification results in a mixture of modified and unmodified oligos. As a consequence, two bands are generally visible on a gel photo after 5' labeling. One band represents a full-length unmodified oligo, and the other band represents a full-length modified oligo. In general, cholesterol-modified oligos can be difficult to dissolve in aqueous solutions. In most cases a freeze/thaw cycle may help to get the oligo into solution. We recommend keeping cholesterol-modified oligos in solution and best purified using rpHPLC.

Purification

Desalt or cartridge (RP1) purification is acceptable for most common phosphoramidite modifiers. However, additional purification is strongly recommended for modifiers that require NHS-ester chemistry to conjugate a dye through an amine linker such as Molecular Probes dyes.

Minimum Guarantee Purified Yield

Due to the chemistry of many modifications, yield will be approximately 40 - 60 % less than a standard oligo. Please see our yield chart for details.

Quality Controls

Every oligo synthesized is strictly controlled for quality by using either MALDI-TOF mass spectrometry or polyacrylamide gel electrophoresis (PAGE) analysis. Final yields are determined using UV absorbance at OD₂₆₀ In addition, we perform QC methods tailored to specific modifications, such as OD ratio measurement where appropriate.

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