Bis-(N,N'-carboxyl-PEG4)-Cy5 | CAS 2107273-44-7

Bis-(N,N'-carboxyl-PEG4)-Cy5 is a Cy5-based fluorescent labeling reagent bearing two PEG4 carboxylate handles that support robust conjugation to amine-containing biomolecules and polymeric materials. Its Cy5 chromophore enables red fluorescence for microscopy and fluorescence-based readouts, while the PEG spacers help improve conjugate solubility and reduce nonspecific interactions in labeling workflows. Researchers use this reagent to generate fluorescent conjugates for imaging, tracking, and assay development where a stable, water-soluble far-red dye is advantageous.

1. Protein And Peptide Labeling

Bis-(N,N'-carboxyl-PEG4)-Cy5 is used by bioconjugation specialists to prepare Cy5-labeled proteins and peptides for fluorescence microscopy and quantitative fluorescence assays. The PEG4 carboxylate functionality provides convenient attachment points for downstream conjugate formation, enabling labeling of antibodies, enzymes, and affinity reagents used in binding studies. In practice, the reagent is commonly selected when red-shifted Cy5 emission is preferred to reduce background from shorter-wavelength fluorophores and when PEG spacing is helpful for maintaining biomolecule performance during labeling.

2. Fluorescence Microscopy Tracing

Bis-(N,N'-carboxyl-PEG4)-Cy5 supports cellular and biomaterial imaging workflows that rely on far-red fluorescence to visualize labeled targets with reduced spectral overlap from common green channels. Imaging teams use Cy5 conjugates generated from this reagent to track labeled biomolecules on surfaces, within experimental matrices, or in microscopy-based localization studies. The PEG4-linked dye format is particularly useful for constructing fluorescent tracers where improved aqueous compatibility and minimized aggregation can help maintain consistent staining intensity across samples.

3. Flow Cytometry Conjugates

Bis-(N,N'-carboxyl-PEG4)-Cy5 is applied in flow cytometry workflows that require a far-red detection channel for fluorescently labeled binding reagents. Cytometry users generate Cy5-conjugated antibodies, ligands, or other affinity constructs from the PEG4 carboxylate dye format to quantify binding to cells or cell-associated targets in fluorescence-based assays. The PEG spacers can be beneficial when preparing conjugates intended to perform reliably across labeling and washing steps, supporting reproducible signal generation in multicolor cytometry panels.

4. Polymer And Surface Functionalization

Bis-(N,N'-carboxyl-PEG4)-Cy5 is used to incorporate far-red fluorescence into polymeric materials and engineered surfaces for materials characterization and molecular adsorption studies. Biomaterials groups employ Cy5-labeled conjugates derived from this reagent to visualize coating uniformity, track functional layer formation, and monitor interactions between labeled biomolecules and material interfaces. The dual PEG4 carboxylate design provides practical flexibility for preparing fluorescently tagged materials used in imaging-based quality control and fluorescence readouts in lab-scale materials R&D.