Description

n-(Azide-Peg3)-N'-(Amine-C3-Amide-Peg4)-Cy5 is a heterobifunctional, cyanine dye-labeled polyethylene glycol (PEG) linker designed for advanced bioconjugation and labeling applications. This compound matters because it combines a photoactivatable azide group for copper-free click chemistry with a primary amine-reactive NHS ester, enabling efficient, site-specific labeling of biomolecules with a near-infrared fluorescent probe. Researchers and developers in the fields of biopharmaceuticals, diagnostics, and life sciences need this reagent for creating stable, fluorescently tagged probes, antibodies, and other biomolecular constructs for imaging, assay development, and targeted delivery systems.

Application

• Fluorescent Labeling of Proteins and Antibodies: Site-specific conjugation via amine groups for creating NIR fluorescent imaging probes and diagnostic reagents.
• Bioconjugation for ADC Development: Facilitating the construction of antibody-drug conjugates (ADCs) or other targeted therapeutics with traceable fluorescent payloads.
• Bioorthogonal Labeling in Live Cells: Utilizing the azide group for strain-promoted azide-alkyne cycloaddition (SPAAC) to label metabolically incorporated alkyne-tagged biomolecules in vivo.
• Surface Functionalization: Modifying nanoparticles, biosensors, or microarray surfaces with fluorescent PEG linkers to enhance biocompatibility and enable detection.
• Proteomics and Biomolecular Interaction Studies: Tagging proteins or peptides to study protein-protein interactions, localization, and trafficking using fluorescence-based techniques.
• Polymer and Material Science: Serving as a functional fluorescent monomer or crosslinker in the synthesis of smart polymeric materials and hydrogels.

Basic Information

Product Name	n-(Azide-Peg3)-N'-(Amine-C3-Amide-Peg4)-Cy5
CAS No.	2107273-70-9
Molecular Formula	C73H112N10O222+ • 2X- (X = counterion)
Molecular Weight	~1500-1600 g/mol (free acid form, exact mass depends on counterion)
Synonyms	Cy5-PEG4-C3-NHS ester-PEG3-Azide; Cy5 NHS ester-PEG4-C3-amide-PEG3-azide; Azido-PEG3-C3-amido-PEG4-Cy5 NHS ester; N-(Azido-PEG3)-N'-(NHS-PEG4-amido-C3)-Cy5; 1-Azido-3,6,9,12-tetraoxapentadecan-15-yl 3-((2,5-dioxopyrrolidin-1-yl)oxy)-3-oxopropyl(17E)-26-((1E,3E)-5-((E)-3-((1E,3E)-5-((2-((2-(2-azidoethoxy)ethoxy)ethyl)amino)-5-oxopenta-1,3-dien-1-yl)penta-1,3-dien-1-yl)-2,3-dihydro-1H-indol-1-ylidene)ethylidene)-2,3,11,12,20,21,23,24-octahydro-1H,10H,19H-4,7:13,16-dimethenodipyrido[2,3-f:2',3'-h]pyrrolo[3,4-g]quinolizine-10,25-dicarboxylate; Azide-PEG3-C3-PEG4-Cy5-NHS; Heterobifunctional Cy5-PEG-Azide/NHS linker.
EINECS	Contact for details

Quality Control

Our n-(Azide-Peg3)-N'-(Amine-C3-Amide-Peg4)-Cy5 is manufactured under strict quality protocols to ensure batch-to-batch consistency and performance in sensitive applications. Each lot undergoes comprehensive analytical characterization, including HPLC for purity, mass spectrometry (MS) for identity confirmation, and NMR for structural verification. Certificates of Analysis (COA) detailing all specifications are provided with every shipment. We adhere to a quality management system and can support development under cGMP guidelines for pharmaceutical applications upon request.

Storage

Preserve in a tightly closed container, protected from light. Store at -20°C ± 5°C under desiccant. This product is hygroscopic (moisture-sensitive) and light-sensitive. Allow the vial to warm to room temperature in a desiccator before opening to prevent condensation and moisture uptake. For long-term storage, keep under an inert atmosphere. Store away from strong acids and oxidizing agents.

Specification

Item	Specification
Appearance	Dark blue to green solid or film
Identification (HPLC-MS)	Conforms to structure
Purity (HPLC)	≥ 95%
Extinction Coefficient (ε)	~250,000 cm-1M-1 at 649 nm (in PBS)
Fluorescence Emission	~670 nm
Water Content (KF)	≤ 1.0%
Solubility	Soluble in DMSO, DMF, acetonitrile, water (with sonication)

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.