DBCO PEG4 NHS Modifier
DBCO-PEG4 NHS ester is a versatile bioorthogonal conjugation reagent used to prepare DBCO-functionalized oligonucleotides from amino-modified DNA, RNA, PNA, aptamers, probes, antisense oligonucleotides, siRNA, and other synthetic nucleic acids. The NHS ester reacts selectively with primary amines to form a stable amide bond, while the DBCO group remains available for strain-promoted azide-alkyne cycloaddition (SPAAC).
The PEG4 spacer provides greater flexibility and hydrophilicity than PEG1 or PEG2 while remaining more compact than PEG8. This intermediate-length linker improves accessibility of the DBCO group, minimizes steric interference during conjugation, and enhances reaction efficiency with azide-modified molecules.
Because SPAAC does not require copper catalysts, DBCO-PEG4 is particularly useful for sensitive biomolecules and live-cell applications where copper-mediated toxicity or nucleic acid degradation is undesirable.
Typical conjugation partners include:
- Azide-modified fluorophores
- Peptides
- Proteins
- Antibodies
- PEG polymers
- Nanoparticles
- Lipids
- Carbohydrates
- Surface coatings
- DNA nanostructures
Typical applications include:
- Copper-free click chemistry (SPAAC)
- Antibody-oligonucleotide conjugates
- Peptide-oligonucleotide conjugates
- Fluorescent labeling
- Nanoparticle functionalization
- Surface immobilization
- Biosensor development
- DNA nanotechnology
- Targeted delivery research
- Diagnostic assay development
Bio-Synthesis offers custom DBCO-PEG4-modified oligonucleotides prepared by post-synthetic conjugation of amino-modified oligonucleotides using DBCO-PEG4 NHS ester.
Technical note: Among the DBCO-PEG linker series, DBCO-PEG4 is often considered the "general-purpose" choice because it provides a good balance of compact size, improved aqueous solubility, reduced steric hindrance, and efficient SPAAC reaction kinetics. Like the PEG1 and PEG8 versions, it is typically used for post-synthetic modification of amino-functionalized oligonucleotides, rather than direct incorporation during automated oligonucleotide synthesis.
Typical Specifications
| Property |
Specification |
| Modification |
DBCO-PEG4 |
| Reagent |
DBCO-PEG4 NHS Ester |
| Reactive Groups |
DBCO (cyclooctyne) and NHS ester |
| Spacer |
PEG4 (tetraethylene glycol) |
| Spacer Characteristics |
Flexible, hydrophilic, reduced steric hindrance |
| Conjugation Chemistry |
SPAAC (Strain-Promoted Azide-Alkyne Cycloaddition) |
| Copper Requirement |
None (Copper-free) |
| Reaction Partner |
Azide-modified molecules |
| Typical Placement |
5′ end, 3′ end, or internal amino-modified positions |
| Compatible Oligonucleotides |
DNA, RNA, PNA, LNA/BNA, siRNA, ASOs, aptamers, probes |
| Typical Applications |
Copper-free click chemistry, antibody conjugation, peptide conjugation, fluorescent labeling, nanoparticle functionalization, biosensors, targeted delivery |
Product Information
Copper-Free Click Chemistry
-20°C To -70°C
Oligonucleotides are stable in solution at 4°C for up to 2 weeks. Properly reconstituted material stored at -20°C should be stable for at least 6 months. Dried DNA (when kept at -20°C) in a nuclease-free environment should be stable for years.
References/Citations:
- Agard NJ, Prescher JA, Bertozzi CR. A strain-promoted [3+2] azide-alkyne cycloaddition for covalent modification of biomolecules in living systems. J Am Chem Soc. 2004;126(46):15046-15047.
- Jewett JC, Bertozzi CR. Cu-free click cycloaddition reactions in chemical biology. Chem Soc Rev. 2010;39:1272-1279.
- Sletten EM, Bertozzi CR. Bioorthogonal chemistry: fishing for selectivity in a sea of functionality. Angew Chem Int Ed. 2009;48:6974-6998.
- Hermanson GT. Bioconjugate Techniques. 3rd Edition. Academic Press; 2013.
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