Description

Cyanine3 Maleimide is a reactive fluorescent dye derivative widely used for site-specific labeling of thiol groups in proteins, peptides, and other biomolecules. Its core value lies in providing a bright, photostable red-orange fluorescent signal, enabling high-sensitivity detection in complex biological assays. This compound is essential for researchers and manufacturers in the fields of bioconjugation, bioimaging, flow cytometry, and diagnostic assay development.

Application

• Protein and Antibody Labeling: Site-specific conjugation to cysteine residues for creating fluorescent probes.
• Bioconjugation for Diagnostics: Development of fluorescently-labeled detection reagents for immunoassays and lateral flow tests.
• Live-Cell and Fixed-Cell Imaging: Tagging of biomolecules for tracking and visualization in microscopy (e.g., confocal, super-resolution).
• Flow Cytometry: Conjugation to antibodies or other ligands for cell surface marker analysis.
• Nucleic Acid Labeling: Modification of thiol-modified oligonucleotides for FISH (Fluorescence In Situ Hybridization) and other genomic applications.
• Drug Delivery & Biotherapeutics: Conjugation to peptides, proteins, or nanoparticles for tracking biodistribution and pharmacokinetics.
• Biomaterial Functionalization: Incorporation of fluorescent labels into hydrogels or polymer scaffolds for research and development.

Basic Information

Product Name	Cyanine3 Maleimide
CAS No.	1838643-41-6
Molecular Formula	C33H38N4O3
Molecular Weight	538.68 g/mol
Synonyms	Cy3 Maleimide; Sulfo-Cyanine3 Maleimide (derivative); Cy3® Maleimide; 2-[(1E,3E)-5-[6-(2,5-Dioxo-2,5-dihydro-1H-pyrrol-1-yl)-1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene]-1,3-pentadien-1-yl]-1,3,3-trimethyl-3H-indolium; Cyanine 3 Maleimide; Maleimide-Cy3; 1H-Indolium, 2-[5-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-1,3-pentadienyl]-1,3,3-trimethyl-6-(2,5-dihydro-2,5-dioxo-1H-pyrrol-1-yl)-, inner salt
EINECS	Contact for details

Quality Control

Our Cyanine3 Maleimide is produced under strict quality management protocols to ensure batch-to-batch consistency and high performance. Each lot undergoes rigorous analytical testing, including HPLC for purity and identity confirmation. A comprehensive Certificate of Analysis (COA) detailing purity, absorbance/emission profiles, and functional performance is provided with every shipment to support your research and development needs.

Storage

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

Specification

Item	Specification
Appearance	Dark red to purple solid
Identification (HPLC/MS)	Conforms to structure
Purity (HPLC)	≥ 95.0%
Absorption Maximum (λmax)	548 - 552 nm
Emission Maximum	562 - 568 nm
Extinction Coefficient (ε)	~150,000 cm-1M-1
Solubility	Soluble in DMSO, DMF, acetonitrile
Water Content (KF)	≤ 2.0%

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