Description

Cyanine5 Maleimide CAS NO 1437796-65-0 is a near-infrared fluorescent dye derivative functionalized with a maleimide group for site-specific bioconjugation to thiols. This compound is critical for creating highly stable, bright, and specific fluorescent probes for advanced bioimaging and diagnostic applications. It is primarily needed by researchers and manufacturers in the fields of biopharmaceutical development, in vivo imaging, flow cytometry, and high-throughput screening.

Application

• Antibody-Drug Conjugate (ADC) Development: Site-specific labeling of engineered cysteine residues on monoclonal antibodies for targeted therapy and biodistribution studies.
• Protein Labeling & Tracking: Conjugation to thiol-containing proteins for fluorescence correlation spectroscopy (FCS), Förster resonance energy transfer (FRET), and cellular localization assays.
• Oligonucleotide & Aptamer Probes: Labeling of thiol-modified DNA, RNA, or aptamers for real-time PCR detection, in situ hybridization, and molecular beacon applications.
• In Vivo & Whole-Animal Imaging: Creation of targeted NIR probes for deep-tissue imaging in preclinical cancer research and pharmacokinetic studies.
• Flow Cytometry & Cell Sorting: Staining of intracellular or cell-surface proteins via thiol-reactive chemistry for multiplexed cell analysis.
• Diagnostic Assay Development: Used as a key component in lateral flow assays, ELISA, and other immunoassays requiring a stable, bright NIR signal.
• Polymer & Nanoparticle Functionalization: Conjugation to thiolated polymers, dendrimers, or nanoparticle surfaces for the development of smart drug delivery systems.

Basic Information

Product Name	Cyanine5 Maleimide
CAS No.	1437796-65-0
Molecular Formula	C37H43N4O3+
Molecular Weight	591.77 g/mol (for cation)
Synonyms	Cy5 Maleimide; Sulfo-Cy5 Maleimide (common variant); Cyanine 5 Maleimide; 1-(5-Carboxypentyl)-2-((1E,3E)-5-((E)-1-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-3,3-dimethyl-5-sulfoindolin-2-ylidene)penta-1,3-dien-1-yl)-3,3-dimethyl-3H-indol-1-ium; Maleimide-Cy5; Cy5® Maleimide (trade name); NIR-664 Maleimide; Thiol-reactive Cy5 dye
EINECS	Contact for details

Quality Control

Our Cyanine5 Maleimide is produced under strict quality management protocols. Each batch undergoes rigorous analytical testing, including HPLC for purity, NMR for structural confirmation, and mass spectrometry for identity verification, to ensure it meets the high standards required for sensitive life science research and diagnostic applications. Certificates of Analysis (COA) with detailed chromatograms and spectral data are provided with every shipment.

Storage

Preserve in a tightly closed container, protected from light. Store desiccated at -20°C or below for long-term stability. 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 hydrolysis.

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]+
Purity (HPLC, 650 nm)	≥ 95.0%
Extinction Coefficient (ε)	~250,000 L·mol⁻¹·cm⁻¹ at ~646 nm (in methanol)
Fluorescence Emission (λmax)	~662 nm
Solubility	Soluble in DMSO, DMF, methanol, acetonitrile
Water Content (KF)	≤ 2.0%

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