DOPA-PEG-azide， Reaction mechanism of dopa polyethylene glycol azide conjugate

1、 Chinese name
The Chinese name for DOPA-PEG-azide is usually dopa polyethylene glycol azide conjugate, abbreviated as DOPA-PEG-N ∝. Among them, DOPA is a natural amino acid containing catechol structure, which has strong hydrophilicity and multifunctional chemical activity; PEG (Polyethylene Glycol) segments provide flexible hydrophilic spacers, improving water solubility and biocompatibility; The terminal azide group (- N3) can participate in copper independent click chemistry (SPAAC) or classical azide olefin cycloaddition reactions, achieving efficient coupling with other molecules. DOPA PEG azide combines hydrophilicity, functional end groups, and multifunctional chemical activity, making it an important tool for the functionalization of biomedicine and nanomaterials.

2、 Chemical structural characteristics

1. DOPA group

• Containing a dihydroxybenzene ring (catechol structure), it provides strong interaction ability with metal ions, proteins, or polymer surfaces.

• DOPA can generate quinone intermediates through oxidation and undergo covalent reactions with thiol or amino groups to achieve surface modification.

• Enable molecules to have self-assembly or adsorption functions, which can be used for the construction of biomaterials and nanocarriers.

2. PEG segment

• Provide flexible water-soluble spacing to increase molecular solubility and improve biocompatibility.

• Chain length can regulate the molecular spatial structure, making it easier for the terminal azide group to approach the target reactant.

3. Azide end

• The terminal azide group is highly reactive and can participate in SPAAC reactions or Huisgen 1,3-dipolar cycloaddition reactions.

• It can form stable triazole rings with cyclic alkyne compounds without copper catalysis, and is suitable for biological systems under mild conditions.

3、 Reaction mechanism

1. SPAAC click response

• Stress promoted cycloaddition reactions occur between the azide end and cyclic alkynes (such as DBCO, BCN).

• Stable covalent bonds are formed through 1,3-dipolar cycloaddition to generate a triazole ring.

• The reaction is efficient, selective, and does not require metal catalysis. It maintains the activity of DOPA and PEG segments under mild conditions.

2. DOPA functional response

• The catechol structure of DOPA can be oxidized to form quinone intermediates, which can form covalent bonds with molecules containing thiol or amino groups (such as Michael addition or Schiff base formation).

• Through this mechanism, DOPA-PEG-N ∝ can be immobilized on protein, nanoparticle, or metal surfaces to achieve functional modification.

3. Mild conditions

• The SPAAC reaction occurs at physiological pH and mild temperature, without affecting proteins or other sensitive biomolecules.

• DOPA oxidative coupling can control reaction rate and selectivity by adjusting pH or oxidant concentration.

4、 Application features

1. Surface functionalization: DOPA-PEG-N ∝ can be immobilized on nanomaterials, metal surfaces, or protein surfaces to achieve controllable modification.

2. Bioorthogonal coupling: The azide group can be coupled with cyclic alkynes under metal free catalytic conditions to maintain the activity of the biological system.

3. Nano carrier construction: DOPA provides hydrophobic or metal interactions, PEG provides water solubility and flexibility, and azide based functionalization is achieved.

4. Multi functional molecular platform: Combining DOPA, PEG, and azide groups, it can achieve drug delivery, fluorescent labeling, or targeted modification.

Product Name: DOPA PEG azide

Purity: 95%+

Characteristic: Solid or liquid

Storage conditions: Dry at -20 ° C and stored away from light

Packaging specifications: 50mg 100mg 250mg 500mg (provided upon request)

Manufacturer: Qiyue Biotechnology

About Us

Qiyue Biotechnology provides customized services for near-infrared fluorescent cyanine dye labeling of various functional groups, such as active esters (NHS esters), maleimide (MAL), azide (N3), alkyne, etc., which facilitate covalent coupling with proteins, peptides, polysaccharides, antibodies, oligonucleotides, nanoparticles, etc. Multiple functional groups can be selected to precisely bind with target molecules, achieving fluorescent modification of proteins, peptides, antibodies, nucleic acids, or nanomaterials. In addition, Qiyue Biotechnology also provides customized dye labeling services, including peptides, proteins, small molecules, sugars and other types of markers, to meet users' personalized applications in scientific research, imaging and other fields.

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For scientific research only, cannot be used for human experiments AXC.2025.09