Cyanine5.5 carboxylic acid is a near-infrared fluorophore bearing a reactive carboxyl group suitable for conjugation with biomolecules. Researchers use it to study long-wavelength fluorescence behavior, energy transfer, and environmental sensitivity. Its extended π-system supports imaging-focused biophysical work.
CAT No: R2498
CAS No:1144107-80-1
Synonyms/Alias:Cyanine5.5 dye;Cyanine5.5 carboxylic acid;Cy5.5-cooh;1144107-80-1;1449661-34-0;BCP30060;
Cyanine5.5 carboxylic acid is a near-infrared (NIR) fluorescent dye belonging to the cyanine family, renowned for its exceptional optical properties and functional carboxylic acid group. This compound stands out due to its strong absorption and emission in the NIR region, which provides significant advantages for imaging applications by minimizing background autofluorescence and enabling deep tissue penetration. Its molecular structure, featuring a carboxylic acid moiety, allows convenient conjugation to biomolecules such as peptides, proteins, and antibodies, making it highly versatile for a variety of research and bioanalytical purposes. The photostability and brightness of Cyanine5.5 carboxylic acid further enhance its suitability for demanding experimental conditions, ensuring consistent and reliable signal detection over extended periods.
Fluorescent Labeling of Biomolecules: Cyanine5.5 carboxylic acid is widely utilized for the covalent labeling of proteins, peptides, oligonucleotides, and other biomolecules via standard amide coupling chemistry. The presence of the carboxylic acid group enables efficient conjugation to primary amines on target molecules, facilitating the creation of highly fluorescent bioconjugates. These labeled entities are invaluable for tracking, localization, and quantification in a variety of in vitro and in vivo experimental models, particularly where NIR fluorescence is advantageous for reducing interference and increasing detection sensitivity.
In Vivo Imaging and Tracking: The NIR fluorescence profile of the dye makes it especially effective for small animal imaging, biodistribution studies, and tracking of labeled cells or nanoparticles in live subjects. By providing deep tissue penetration and low background signal, Cyanine5.5 derivatives allow researchers to visualize biological processes in real time, monitor disease progression, or assess the delivery efficiency of therapeutic agents. Its integration into imaging probes supports non-invasive longitudinal studies, offering insights into dynamic biological events with high spatial and temporal resolution.
Development of Biosensors and Diagnostic Assays: Cyanine5.5 carboxylic acid plays a pivotal role in the construction of biosensors and diagnostic platforms, where its fluorescence properties are harnessed for sensitive detection of analytes. By attaching the dye to recognition elements such as antibodies or aptamers, researchers can develop assays that produce a quantifiable NIR fluorescent signal upon target binding. This capability is particularly valuable in multiplexed detection systems, enabling simultaneous monitoring of multiple biomarkers with minimal spectral overlap and high signal-to-noise ratios.
Fluorescence Resonance Energy Transfer (FRET) Applications: The spectral characteristics of Cyanine5.5 make it an excellent acceptor or donor in FRET-based assays, which are essential for studying molecular interactions, conformational changes, and enzymatic activities. By pairing the dye with appropriate FRET partners, scientists can design experiments that report on proximity relationships or dynamic events within complex biological systems. The NIR emission further allows FRET measurements in environments where traditional visible-wavelength dyes are less effective due to autofluorescence or light scattering.
Nanoparticle and Surface Modification: Cyanine5.5 carboxylic acid is frequently employed to functionalize nanoparticles, liposomes, or other nanocarriers for imaging and tracking purposes. By covalently attaching the dye to the surface of these carriers, researchers can monitor their biodistribution, cellular uptake, or targeting efficiency in real time. This approach is instrumental in nanomedicine research, where visualization of drug delivery vehicles in biological systems provides critical data for optimizing formulation and therapeutic strategies.
Photostability and Multiplexed Imaging: The robust photostability and distinct spectral properties of Cyanine5.5 carboxylic acid also make it a preferred choice for multiplexed fluorescence imaging. In multi-color experiments, the dye's NIR emission can be combined with other fluorophores to simultaneously monitor different targets within the same sample. This capability is particularly beneficial in complex biological environments, where distinguishing between various molecular species is essential for comprehensive analysis. The combination of high brightness, stability, and flexible conjugation chemistry ensures that Cyanine5.5 carboxylic acid remains a valuable tool in advanced fluorescence imaging and molecular research applications.
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