N-(m-PEG4)-N'-(PEG2-acid)-Cy5 | CAS 2107273-24-3

N-(m-PEG4)-N'-(PEG2-acid)-Cy5 is a Cy5-based fluorescent dye conjugated to polyethylene glycol (PEG) chains that include a carboxylic acid handle for downstream bioconjugation. The PEGylated design improves aqueous compatibility and conjugate handling for fluorescence labeling workflows, while the Cy5 chromophore provides a far-red emission signal commonly used in fluorescence imaging and labeling experiments.

1. Antibody And Protein Labeling

N-(m-PEG4)-N'-(PEG2-acid)-Cy5 is frequently used to prepare far-red fluorescent conjugates for immunofluorescence and protein tracking, where researchers need stable dye loading and convenient attachment to biomolecules. The PEG spacer architecture helps reduce aggregation and supports consistent labeling during antibody or protein conjugate preparation, while the terminal carboxylic acid functionality enables coupling strategies to amine-bearing targets or incorporation into activated ester workflows for research-grade labeling reagents.

2. Peptide, Ligand, to Biomolecule Conjugates

N-(m-PEG4)-N'-(PEG2-acid)-Cy5 supports fluorescent tagging of peptides and small-molecule ligands used in binding studies, receptor profiling, and molecular imaging reagent development. In these workflows, the PEG components help maintain solubility and reduce nonspecific dye clustering, which is particularly helpful when conjugates are used at low labeling densities. The carboxylic acid handle provides a practical functional group for building fluorescent biomolecule conjugates for microscopy and plate-based fluorescence readouts.

3. Fluorescence Microscopy Tracing

N-(m-PEG4)-N'-(PEG2-acid)-Cy5 is used as a far-red imaging label in fluorescence microscopy experiments that benefit from reduced background relative to shorter-wavelength probes. Researchers apply Cy5-based conjugates to visualize labeled biomolecules in fixed-cell or in vitro imaging contexts, leveraging the dye's bright emission and the PEGylated linker to improve handling in aqueous staining buffers. This format is commonly integrated into multicolor imaging panels where far-red channels reduce spectral overlap with visible fluorophores.

4. Surface And Polymer Functionalization

N-(m-PEG4)-N'-(PEG2-acid)-Cy5 can be incorporated into labeled materials for biomaterials research and surface engineering, taking advantage of the carboxylic acid functionality for coupling to activated surfaces or polymer matrices. Materials scientists use Cy5-PEG conjugates to create fluorescently addressable coatings, labeling reagents for nanoparticles, or traceable polymer constructs for imaging and characterization. The PEGylated scaffold helps maintain dye dispersion in aqueous processing steps, supporting reproducible fluorescence for material tracking experiments.