Description

Cy5 Acid (Mono So3) is a reactive, water-soluble, near-infrared fluorescent dye derivative, specifically a sulfonated cyanine 5 carboxylic acid. Its core value lies in its excellent photostability, high molar absorptivity, and emission in the far-red to near-infrared region, minimizing background interference in biological samples. This compound is essential for researchers and manufacturers in bioconjugation, fluorescence labeling, and in vivo imaging, serving the biotechnology, pharmaceutical, and diagnostic industries.

Application

• Bioconjugation and Probe Synthesis: Used as a reactive intermediate for labeling antibodies, proteins, peptides, and oligonucleotides with a near-infrared fluorophore.
• In Vivo and Small Animal Imaging: Enables deep-tissue imaging applications due to its NIR emission, which penetrates tissue more effectively than visible light.
• Flow Cytometry and Fluorescence Microscopy: Serves as a key fluorescent tag for cellular and subcellular analysis.
• Diagnostic Assay Development: Incorporated into lateral flow assays, ELISA, and other immunoassays as a detection label.
• Material Science and Sensor Development: Functionalized onto nanoparticles, polymers, or surfaces to create fluorescent sensors and smart materials.
• DNA Sequencing and Microarray Analysis: Acts as a fluorescent dye for nucleic acid labeling and detection.

Basic Information

Product Name	Cy5 Acid (Mono So3)
CAS No.	644979-16-8
Molecular Formula	C35H42N2O7S2+ (commonly listed as a salt, e.g., sodium salt)
Molecular Weight	666.85 g/mol (Free acid form)
Synonyms	Sulfo-Cyanine5 carboxylic acid; Cy5™ Mono NHS Ester precursor; 1-(5-Carboxypentyl)-2-((1E,3E)-5-(1-(5-sulfonatopentyl)-3,3-dimethylindolin-2-ylidene)penta-1,3-dien-1-yl)-3,3-dimethyl-3H-indol-1-ium; Sulfo-Cy5 acid; Cyanine5 sulfonated acid; Near-IR fluorescent dye acid; Reactive Cy5 derivative.
EINECS	Contact for details

Quality Control

Our Cy5 Acid (Mono So3) is produced under strict quality management protocols. Each batch undergoes rigorous analytical testing, including HPLC for purity, NMR and MS for structural confirmation, and spectrophotometry for optical property verification. A comprehensive Certificate of Analysis (COA) detailing purity, absorbance/emission maxima, and extinction coefficient is provided to ensure compliance with your research and manufacturing standards.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry place at -20°C or below for long-term stability. This product is hygroscopic (moisture-sensitive). Allow the sealed vial to equilibrate to room temperature before opening to minimize condensation. For optimal performance, desiccate after opening.

Specification

Item	Specification
Appearance	Dark blue to green solid
Identification (HPLC/MS)	Conforms to structure
Purity (HPLC)	≥95.0%
Absorption Maximum (λmax)	646 - 652 nm
Emission Maximum (λem)	662 - 668 nm
Extinction Coefficient (ε)	≥ 200,000 L·mol⁻¹·cm⁻¹
Water Content (KF)	≤ 5.0%
Solubility	Soluble in water, DMSO, DMF

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