N-(m-PEG4)-N'-(amino-PEG3)-Cy5 | CAS 2107272-96-6

N-(m-PEG4)-N'-(amino-PEG3)-Cy5 is a Cy5-based fluorescent labeling reagent featuring a PEG spacer architecture and a terminal amino functional group for conjugation to amine-reactive handles on biomolecules and materials. Its long-wavelength Cy5 fluorescence supports sensitive red-channel imaging workflows in microscopy and fluorescence-based assays, while the PEG spacers help improve conjugate solubility and reduce nonspecific interactions in labeling and detection experiments.

1. Protein And Peptide Labeling

N-(m-PEG4)-N'-(amino-PEG3)-Cy5 is used by protein and peptide chemistry groups to prepare fluorescent conjugates for fluorescence microscopy, fluorescence imaging assays, and binding studies. Researchers commonly incorporate the Cy5 signal into antibodies, affinity reagents, enzymes, and peptide probes where a red fluorophore is preferred for multiplexing or reduced background from short-wavelength autofluorescence. The PEG spacers and terminal amino functionality support downstream conjugation strategies that yield more uniform, water-compatible labeling reagents for bioconjugation workflows.

2. Antibody Conjugate Development

N-(m-PEG4)-N'-(amino-PEG3)-Cy5 supports antibody conjugation programs where red fluorescence readouts are required for immunofluorescence staining and quantitative fluorescence assays. Laboratories developing immunoreagents for target localization or assay development often select Cy5 labeling to align with common fluorescence imaging filter sets and to facilitate multicolor experiments. The PEGylated structure helps maintain conjugate dispersion in aqueous buffers, which is particularly useful when preparing antibody-fluorophore constructs for imaging and flow-adjacent fluorescence measurements.

3. Fluorescent Bioconjugation Standards

N-(m-PEG4)-N'-(amino-PEG3)-Cy5 is frequently used to generate fluorescent reference conjugates and calibration materials for assay development and method verification in fluorescence workflows. In practice, researchers prepare Cy5-labeled control reagents to validate labeling consistency, monitor reagent stability across experiments, and support instrument setup in the red spectral channel. The PEG spacing and amine functionality help produce reproducible labeling constructs that behave consistently in buffer-based fluorescence measurements, supporting routine QA/QC-style checks during probe and conjugate development.

4. Polymer And Surface Labeling

N-(m-PEG4)-N'-(amino-PEG3)-Cy5 is applied in biomaterials and materials research to introduce Cy5 fluorescence into PEG-containing polymers and surface-modified constructs. Teams working on hydrogel labeling, coating development, and fluorescent material tagging use the terminal amino functionality to connect the dye to amine-reactive surface chemistries or polymer functional groups. This enables visualization of labeled materials in fluorescence microscopy and supports tracking of labeled biomaterial components in composite systems where reduced nonspecific adsorption from PEG spacers is beneficial.