Description

Sulfo-Cy5.5 Maleimide is a near-infrared fluorescent labeling reagent designed for the site-specific conjugation of biomolecules via thiol groups. This water-soluble, sulfonated cyanine dye derivative is essential for creating stable, bright conjugates with minimal impact on the biological activity of the target protein or peptide. It is a critical tool for researchers and developers in biopharmaceuticals, in vivo imaging, and diagnostic assay development who require high-performance, low-background labeling for sensitive detection applications.

Application

• Antibody-Drug Conjugate (ADC) Development: Site-specific conjugation of cytotoxic payloads or fluorescent probes to engineered cysteine residues on monoclonal antibodies.
• Protein & Peptide Labeling: Fluorescent tagging of thiol-containing proteins (e.g., engineered cysteines, reduced disulfide bonds) for tracking, purification, and functional studies.
• In Vivo Imaging Probes: Conjugation to targeting ligands (e.g., peptides, antibodies) for near-infrared fluorescence (NIRF) imaging in preclinical animal models.
• Diagnostic Assay Reagents: Labeling of detection antibodies or proteins in lateral flow assays, ELISA, and other immunoassays.
• Bioconjugation & Chemical Biology: A versatile tool for creating custom fluorescent biomolecular constructs for research and development.
• Nanoparticle Functionalization: Conjugation to thiolated surfaces of quantum dots, gold nanoparticles, or liposomes for multimodal imaging applications.

Basic Information

Product Name	Sulfo-Cy5.5 Maleimide
CAS No.	2183440-58-4
Molecular Formula	C46H51KN4O13S3 (Potassium salt form)
Molecular Weight	~1035.3 g/mol
Synonyms	Sulfo-Cyanine5.5 Maleimide; Cy5.5 Maleimide, sulfonated; Sulfo-Cy5.5 Mal; 2,5-Dioxopyrrolidin-1-yl 3-((1E,3E)-5-((E)-1-(5-((2,5-dioxopyrrolidin-1-yl)oxy)-5-oxopentyl)-3,3-dimethyl-5-sulfo-1-(3-sulfopropyl)indolin-2-ylidene)penta-1,3-dien-1-yl)-1,1-dimethyl-3-(3-sulfopropyl)-3H-indol-1-ium-5-sulfonate; NIR dye maleimide; Water-soluble Cy5.5 Maleimide
EINECS	Contact for details

Quality Control

Our Sulfo-Cy5.5 Maleimide is manufactured under strict quality management systems. Each batch undergoes rigorous analytical testing to ensure high purity, consistent performance, and batch-to-batch reproducibility critical for research and development. Certificates of Analysis (COA) detailing purity (HPLC), identity (MS, NMR), absorbance/fluorescence properties, and functional performance are available upon request.

Storage

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

Specification

Item	Specification
Appearance	Dark blue to green solid
Identification (HPLC/MS)	Conforms to structure
Purity (HPLC)	≥ 95%
Absorption Maximum (λmax)	~ 683 nm
Emission Maximum (λem)	~ 703 nm
Extinction Coefficient (ε)	Contact for details
Solubility	Soluble in water, DMSO, PBS
Functional Performance	Conjugation efficiency verified

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