Click Chemistry

The Huisgen 1,3-dipole cycloaddition of azide and alkyne (click chemistry) provides simple reaction conditions for small molecules and biomolecules. The non-catalytic reaction (AAC) needs to be carried out at high temperatures with harsh reaction conditions and a slow rate, and the mixture of 1,5- and 1,4- triazole will be obtained. The copper ion-catalyzed reaction (CuAAC) is one of the most widely used due to its high efficiency and good specificity, and the product is 1,2,3-triazole. The application of azide-alkyne cycloaddition reaction catalyzed by ruthenium (RuAAC) is increasing rapidly. A more friendly click method is the cycloaddition reaction promoted by strains (SPAAC), which avoids the use of metal catalysts.

Fig.1 Different synthetic routes in Huisgen 1,3-dipole cycloaddition of azide-alkyne. (Perrone, et al., 2021)

Azide-Modified Oligonucleotides

The addition of the azide group is usually achieved by the reaction of a primary amino-modified oligonucleotide with an azide-activated NHS ester, which attaches the azide group to the 5' terminal, 3' terminal, or interior of the oligonucleotide via an amide bond. Further, functional labels such as fluorescence, biotin, alkaline phosphatase, antibodies, etc. can be attached to oligonucleotides by click chemistry.

Fig.2 Labeling oligonucleotide by click chemistry. (CD BioGlyco)

Azide-based Oligonucleotide Modification Service at CD BioGlyco

CD BioGlyco has superb synthesis technology to provide a variety of azide-modified oligonucleotides and meet the different needs of customers. We offer 5'-, 3'-, and internal azide modification services. Please feel free to choose the suitable linker modification for your needs.

• 5'-Azide linker: 5'-Azide modification can be achieved by the reaction of amino-linked oligonucleotides and azide-activated NHS esters. An azide linker connected by an amide bond will be obtained (5'-azide C3 NHS linker). CD BioGlyco also has 5'-azide modifier (5'-azide C6 linker) linked by an alkane spacer (C6). In addition, adding an azide chain directly to ribose is also a viable strategy, and we provide 5'-azide thymine deoxynucleotide (5'-azide dT) to achieve the goal.

Fig.3 Chemical structures of 5'-azide C3 NHS linker, 5'-azide C6 linker, and 5'-azide dT. (CD BioGlyco)

• 3'-Azide linker: When introducing an azide group at the 3' end of an oligonucleotide, the 3'-azide C3 NHS linker is a good choice. CD BioGlyco offers 3'-azide C3 NHS linkers with different structures depending on the amino linkage strategy.

Fig.4 3'-Azide C3 NHS linkers with different structures. (CD BioGlyco)

• Internal azide linker: Replacing the original dT in the oligonucleotide with an azide-modified dT allows easy insertion of the azide terminal into the interior of the oligonucleotide (internal azide dT).

Fig.5 Chemical structure of internal azide dT. (CD BioGlyco)

Applications

• Development of multiplex protein detection in single cells.
• Preparation of oligonucleotide-coupled antibodies.
• Biorthogonal labeling and functionalization.
• Developing nucleic acid therapeutics.
• Preparation of functional oligonucleotides.

Advantages

• Mild reaction conditions (aqueous solution and room temperature).
• Almost no side reaction.
• No functional group interference.
• Stable triazole connection.
• Azide-modified oligonucleotide products with high purity.
• Thoughtful after-sales service.

CD BioGlyco also has the strategy to link functional labels to oligonucleotides by click chemistry which involves Alkyne-based Oligonucleotide Modification. If you are interested in this service or you do not find the linker modifications you need, please feel free to contact us to get a custom solution for you.