Cy5-PEG6-NHS ester

Cy5-PEG6-NHS ester is a Cy5-based NHS ester labeling reagent designed for efficient amide-bond formation with primary amines on proteins and other biomolecules. The PEG6 spacer helps reduce steric crowding and supports conjugate formation with improved handling in aqueous labeling workflows. Cy5 fluorescence enables bright far-red detection for fluorescence microscopy, imaging-based assays, and flow cytometry-compatible conjugates when excitation/emission instrumentation matches the Cy5 spectral window.

1. Protein Antibody Labeling

Cy5-PEG6-NHS ester is widely used by antibody and protein engineering groups to generate far-red fluorescent immunoconjugates for binding studies and imaging workflows. Researchers typically label lysine-rich antibodies, enzyme conjugates, and affinity reagents to produce fluorescent probes for target visualization in cell-based assays and microscopy experiments. The NHS ester reactivity toward primary amines makes it a practical choice for preparing labeled secondary antibodies, staining reagents, and calibration conjugates used in fluorescence readouts.

2. Fluorescence Microscopy Labeling

Cy5-PEG6-NHS ester supports fluorescence microscopy workflows where far-red imaging helps minimize background from autofluorescence and enables multiplex-friendly staining schemes. Labeling of proteins, peptides, and protein-based ligands with this reagent is commonly used to visualize biomolecular localization on fixed samples and in fluorescence imaging assays that rely on Cy5 signal detection. The PEG6 linker provides spacing that can help preserve binding behavior of labeled biomolecules when constructing imaging reagents for cellular and biomaterial-associated studies.

3. Flow Cytometry Conjugate Preparation

Cy5-PEG6-NHS ester is used to prepare Cy5-labeled biomolecule conjugates for flow cytometry panels that require far-red fluorescence channels. By targeting accessible primary amines on antibodies, protein probes, and other lysine-containing reagents, laboratories generate fluorescent staining reagents for cell-surface or extracellular biomolecule detection in research cytometry workflows. This reagent is particularly useful when building multicolor experiments that benefit from Cy5's emission separation from common fluorophores.

4. Biomaterial Surface Functionalization

Cy5-PEG6-NHS ester is also applied in biomaterials research to fluorescently tag surfaces and coatings through amine-reactive coupling to amine-containing materials. Researchers use it to incorporate far-red fluorescent markers into polymer films, hydrogel systems, and functionalized substrates for imaging-based tracking, coating verification, and material localization studies. The PEG6 spacer contributes to more uniform labeling on complex surfaces, supporting reproducible fluorescence readouts during microscopy and imaging characterization.