N-(m-PEG4)-N'-hydroxypropyl-Cy5 | CAS 2107273-20-9

N-(m-PEG4)-N'-hydroxypropyl-Cy5 is a PEGylated Cy5 fluorescent dye designed to improve aqueous handling and conjugation flexibility for fluorescence labeling workflows. The Cy5 chromophore provides far-red excitation/emission performance commonly used for low-background imaging and multicolor experiments, while the hydroxypropyl functionality supports downstream derivatization and stable incorporation into labeled biomolecules and materials.

1. Fluorescent Conjugate Labeling

N-(m-PEG4)-N'-hydroxypropyl-Cy5 is frequently used by chemical biology and bioconjugation groups to generate far-red fluorescent conjugates for tracking biomolecules in solution and on surfaces. Researchers employ the PEG spacer to reduce non-specific interactions and to support more consistent labeling behavior when coupling Cy5 into peptides, proteins, affinity reagents, or other macromolecules intended for fluorescence imaging and assay readouts. The resulting Cy5 conjugates are commonly incorporated into labeling kits and custom probe constructs for microscopy-based localization and fluorescence-based quantification.

2. Fluorescence Microscopy Imaging

N-(m-PEG4)-N'-hydroxypropyl-Cy5 supports fluorescence microscopy workflows where far-red signal is preferred to minimize interference from shorter-wavelength autofluorescence. Imaging teams use Cy5-based labeling to visualize labeled targets in fixed or prepared samples, including labeled biomolecular assemblies and fluorescently tagged reagents used as imaging handles for cellular or extracellular structures. PEGylation helps maintain dye dispersion in aqueous imaging buffers, supporting reproducible staining intensity across experiments and facilitating multicolor experimental design where Cy5 serves as a spectrally distinct channel.

3. Flow Cytometry Fluorescent Labeling

N-(m-PEG4)-N'-hydroxypropyl-Cy5 is used in flow cytometry development to produce far-red fluorescent labeling reagents for cell analysis and fluorescence-based sorting. Assay developers and core facilities often select Cy5 for its compatibility with common cytometer laser/filter sets and for its ability to reduce spectral overlap with green and orange fluorophores in multicolor panels. The PEGylated dye format helps support consistent reagent preparation for staining protocols used to quantify fluorescence intensity and to track labeled biomolecular binding events in suspension workflows.

4. Biomaterial Surface Tagging

N-(m-PEG4)-N'-hydroxypropyl-Cy5 is applied in biomaterials science to fluorescently tag polymers, hydrogels, and surface-modified substrates for visualization of coating uniformity, material distribution, and reagent immobilization. Materials researchers use the PEGylated Cy5 format to incorporate far-red fluorescence into functional surfaces intended for microscopy readouts, enabling tracking of labeled components during material fabrication and downstream characterization. This approach is also used to create fluorescent standards for imaging-based quality control of labeled coatings and immobilized conjugates.