Alexa Dye Oligo Labeling

These dyes are available as NHS Esters and are conjugated post synthesis to an amino-modified oligo and two step HPLC purifications are required. The spectral diversity of the Alexa Fluor dyes make them ideal tools for multicolor applications such as fluorescence in situ hybridization (FISH) and microarray experiments. Our wide selection of dyes spans the visible spectrum and beyond, providing enormous flexibility in choosing a label that is compatible with microarray scanners and fluorescence microscopes.

The Alexa Fluor dyes have several properties that make them superior to other fluorescent dyes:

Oligonucleotides labeled with Alexa Fluor have many advantages:

• High water solubility.The Alexa Fluor dyes are highly water soluble, making them ideal for hybridization experiments. Nucleic acids labeled with the Alexa Fluor dyes do not aggregate or precipitate, even in high-salt conditions.
• pH independence. Fluorescence of the Alexa Fluor conjugates is not pH sensitive in the ranges used for hybridization solutions and microscopy mounting media.
• Resistance to photobleaching. The enhanced photostability of Alexa Fluor dyes makes them ideal for applications requiring imaging, such as FISH and microarrays.
• High signal correlation.
  

The Alexa Fluor 555/Alexa Fluor 647 dye pair provides better signal correlation and therefore higher resolution of diff erentially expressed genes than the commonly used Cy3/Cy5 dye pair

Similar alternatives include the DyLight Fluors and the Atto.

Contact your Account Representative for pricing on Alexa dye labeled oligonucleotides. For additional information, please Contact us.

Price/labeling, purification and synthesis is an additional charge

Purification

A wide variety of modifications can be incorporated into an oligonucleotide at the time of synthesis, using aspecialized phosphoramidite chemistries for labeling. However, certain modifications require the use of post-synthetic conjugation strategies in which a primary amine modified oligonucleotide is covalently attached to a dye via NHS ester chemistry. Other cross-linking chemistries are also available depending on particular project specifications. Single HPLC purification is recommended when using phosphoramidite oligo chemistry, otherwise dual HPLC is required for post-synthetic labeling.

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.

Contact us for more.