Description

Cy5-NHS Ester is a reactive, near-infrared fluorescent labeling reagent widely used for the covalent conjugation of biomolecules. Its core value lies in providing a stable, high-quantum-yield fluorescent tag with minimal spectral overlap, enabling sensitive detection and imaging. This compound is essential for researchers and manufacturers in biotechnology, pharmaceutical development, and diagnostic assay production who require reliable and efficient protein, antibody, or oligonucleotide labeling.

Application

• Protein and Antibody Labeling: Conjugation to primary amines (lysine residues) for fluorescence-activated cell sorting (FACS), western blotting, and immunofluorescence microscopy.
• Nucleic Acid Probes: Labeling of oligonucleotides, primers, and probes for in situ hybridization (FISH) and real-time PCR applications.
• Bioconjugation for Diagnostics: Development of fluorescent lateral flow assays, microarrays, and biosensors for clinical and research diagnostics.
• In Vivo and In Vitro Imaging: Preparation of labeled peptides, antibodies, or nanoparticles for near-infrared fluorescence (NIRF) imaging in preclinical studies.
• Biomaterial and Polymer Labeling: Tagging of amine-functionalized polymers, hydrogels, or surfaces to study material interactions and cellular uptake.
• Proteomics and Biomolecular Interaction Studies: Use in fluorescence polarization (FP), Förster resonance energy transfer (FRET), and other biophysical assays to study molecular interactions.

Basic Information

Product Name	Cy5-NHS Ester
CAS No.	350686-88-3
Molecular Formula	C37H45N3O6
Molecular Weight	627.78 g/mol
Synonyms	Cy5 NHS Ester; Cyanine5 NHS Ester; Sulfo-Cyanine5 NHS Ester (note: often confused with non-sulfo version); 1-(5-Carboxypentyl)-1'-ethyl-3,3,3',3'-tetramethylindodicarbocyanine-5,5'-disulfonate NHS Ester; Cy5® NHS Ester (trade name); N-Hydroxysuccinimide ester of Cy5; Cy5 carboxylic acid succinimidyl ester
EINECS	Contact for details

Quality Control

Our Cy5-NHS Ester is manufactured under strict quality management systems. Each batch undergoes rigorous analytical testing, including HPLC for purity and identity confirmation, to ensure it meets the high standards required for sensitive life science applications. A comprehensive Certificate of Analysis (COA) detailing purity, absorbance, fluorescence, and moisture content is provided with every shipment.

Storage

Preserve in a tightly closed container, protected from light. Store desiccated at -20°C or below. This product is hygroscopic (moisture-sensitive) and strictly light-sensitive (protect from all light exposure). Allow the vial to equilibrate to room temperature in a desiccator before opening to prevent condensation and hydrolysis.

Specification

Item	Specification
Appearance	Dark blue to purple solid
Identification (HPLC/UV-Vis)	Conforms
Purity (HPLC)	≥ 95.0%
Absorbance (λmax)	646 - 652 nm
Extinction Coefficient (ε)	≥ 250,000 L·mol⁻¹·cm⁻¹
Fluorescence Emission (λmax)	662 - 668 nm
Water Content (KF)	≤ 2.0%
Solubility	Soluble in DMF, DMSO, acetonitrile

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