Description

n-(Azide-PEG3)-N'-(PEG4-Acid)-Cy5 is a heterobifunctional, cyanine dye-labeled polyethylene glycol (PEG) linker designed for bioorthogonal conjugation and fluorescence labeling. This compound matters for researchers and developers as it combines a photo-stable near-infrared fluorophore with orthogonal reactive groups—an azide for copper-free click chemistry and a carboxylic acid for amine coupling—enabling the construction of complex biomolecular probes. It is primarily needed by professionals in bioconjugation, pharmaceutical R&D, and diagnostic assay development for creating targeted imaging agents, antibody-drug conjugates (ADCs), and advanced cellular probes.

Application

• Bioconjugation and Probe Development: Site-specific labeling of antibodies, proteins, peptides, and oligonucleotides via the azide (strain-promoted alkyne-azide cycloaddition, SPAAC) and carboxylic acid (EDC/NHS coupling) functionalities.
• Antibody-Drug Conjugate (ADC) Research: Facilitating the construction of fluorescently labeled ADCs or linker-payload intermediates for tracking and efficacy studies.
• In Vitro and In Vivo Imaging: Synthesis of near-infrared (NIR) fluorescent probes for deep-tissue imaging, cell tracking, and biodistribution studies due to the Cy5 fluorophore's emission profile.
• Diagnostic Assay Development: Creating fluorescent detection reagents for immunoassays, flow cytometry, and fluorescence microscopy.
• Polymer and Material Science: Functionalizing surfaces, nanoparticles, or hydrogels with fluorescent PEG tethers for biomedical applications.
• Chemical Biology and Proteomics: As a tool compound for labeling and visualizing cellular targets in live or fixed cells using bioorthogonal chemistry.

Basic Information

Product Name	n-(Azide-PEG3)-N'-(PEG4-Acid)-Cy5
CAS No.	2107273-42-5
Molecular Formula	C58H84N8O15
Molecular Weight	1109.3 g/mol (Theoretical)
Synonyms	Cy5-PEG3-Azide-PEG4-Acid; Cy5-Azide-PEG3-PEG4-COOH; N-(Azido-PEG3)-N'-(PEG4-carboxylic acid)-Cyanine5; Azide-PEG3-Cy5-PEG4-Acid; 1-Azido-3,6,9-trioxaundecan-11-yl 2,5,8,11-tetraoxatetradecan-14-oate Cy5 derivative; Cyanine5 azide PEG acid; Heterobifunctional Cy5 PEG linker; NIR fluorescent PEG crosslinker.
EINECS	Contact for details

Quality Control

Our n-(Azide-PEG3)-N'-(PEG4-Acid)-Cy5 is produced under strict quality protocols to ensure batch-to-batch consistency and performance in sensitive applications. Each lot is characterized by HPLC, NMR, and mass spectrometry to verify identity, purity, and functional group integrity. Certificates of Analysis (COA) detailing these specifications are available upon request.

Storage

Preserve in a tightly closed container, protected from light. Store at -20°C or below under desiccant. This compound is hygroscopic (moisture-sensitive) and light-sensitive. Allow the vial to equilibrate to room temperature in a dry environment before opening to minimize moisture uptake.

Specification

Item	Specification
Appearance	Dark blue to purple solid or film
Identification (HPLC)	Retention time corresponds to reference standard
Identification (MS)	Consistent with molecular ion [M+H]+
Purity (HPLC)	≥ 95% (Area percentage at 650 nm)
Water Content (KF)	≤ 1.0%
Functional Group Integrity	Azide and carboxylic acid groups confirmed by NMR

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