N-(m-PEG4)-N'-(PEG2-NHS ester)-Cy5 | CAS 2107273-28-7

N-(m-PEG4)-N'-(PEG2-NHS ester)-Cy5 is a PEGylated Cy5 NHS ester labeling reagent designed for efficient conjugation to primary amines on biomolecules, surfaces, and affinity materials. The Cy5 fluorophore provides red fluorescence for microscopy and fluorescence-based assays, while the PEG spacers help improve conjugate solubility and reduce steric constraints during bioconjugation.

1. Protein And Antibody Labeling

N-(m-PEG4)-N'-(PEG2-NHS ester)-Cy5 is widely used in fluorescent labeling workflows for proteins, including antibodies, antibody fragments, enzymes, and protein standards. Researchers typically employ the NHS ester to covalently attach Cy5 to lysine residues and N-terminal amines, generating stable fluorescent conjugates for binding studies, reagent development, and fluorescence imaging. The PEG linkers contribute to more uniform labeling and help maintain functional performance of larger biomolecules when conjugation is performed under standard amine-labeling conditions.

2. Flow Cytometry Fluorescent Conjugates

N-(m-PEG4)-N'-(PEG2-NHS ester)-Cy5 supports red-channel fluorescence labeling for flow cytometry panels where Cy5 emission is used to track specific binding events or cell-associated targets. By reacting the NHS ester with amine-containing capture reagents such as antibodies or labeling proteins, laboratories generate Cy5-conjugated reagents that can be used for cell staining, receptor binding characterization, and multiplex fluorescence experiments. The PEGylated structure is particularly helpful when preparing conjugates that must remain soluble and reproducible across staining and wash steps.

3. Fluorescence Microscopy Tracing

N-(m-PEG4)-N'-(PEG2-NHS ester)-Cy5 is used to produce Cy5-labeled biomolecules for fluorescence microscopy, including tracking of labeled proteins in fixed samples and imaging of fluorescent conjugates in cell-associated contexts. Because the reagent is an NHS ester, it is commonly incorporated into labeling strategies for amine-rich targets such as extracellular matrix proteins, cell-surface binding reagents, and fluorescent standards. The combination of Cy5 brightness and PEG spacing supports practical imaging workflows where consistent labeling and manageable background are required for visualizing biomolecular localization patterns.

4. Surface And Biomaterial Functionalization

N-(m-PEG4)-N'-(PEG2-NHS ester)-Cy5 is also used for fluorescent surface modification of amine-bearing materials, enabling visualization of functionalized coatings and biomaterial interfaces. Researchers apply the NHS ester to introduce Cy5 onto amine-functionalized surfaces such as polymer films, hydrogel matrices, and derivatized nanoparticles used in materials research. The PEG spacers help reduce nonspecific aggregation of the dye-modified layer and support stable fluorescence labeling for surface mapping, coating verification, and fluorescence-based characterization of engineered materials.