N-(m-PEG4)-N'-(Biotin-PEG2-Amido-PEG4)-Cy5

N-(m-PEG4)-N'-(Biotin-PEG2-Amido-PEG4)-Cy5 is a PEGylated Cy5 fluorescent conjugate bearing a biotin handle, designed for fluorescence labeling workflows that benefit from reduced nonspecific interactions and improved conjugate handling. The Cy5 fluorophore enables red fluorescence readouts for microscopy and fluorescence-based assays, while the biotin moiety supports strong streptavidin/avidin capture for targeted immobilization, pull-down, and assay signal organization. This combination is commonly used in chemical biology and biomaterials research where controlled attachment of fluorescent probes to biotin-binding surfaces is required.

1. Streptavidin Capture Labeling

N-(m-PEG4)-N'-(Biotin-PEG2-Amido-PEG4)-Cy5 is frequently used to generate streptavidin-anchored fluorescent reagents for imaging and assay development. Researchers immobilize the conjugate onto streptavidin-coated plates, beads, or biosensor surfaces to create stable fluorescent interfaces for washing steps and repeated measurements. The PEG spacers help maintain Cy5 accessibility and reduce steric hindrance, supporting consistent fluorescence intensity across labeling and immobilization workflows.

2. Fluorescence Microscopy Tracing

N-(m-PEG4)-N'-(Biotin-PEG2-Amido-PEG4)-Cy5 supports red-channel fluorescence microscopy experiments that require biotin-mediated localization. In cell and biomolecule imaging studies, the biotin handle is leveraged to attach the Cy5 label to biotin-binding partners on surfaces, scaffolds, or affinity reagents, enabling visualization of labeled complexes with reduced background from nonspecific adsorption. This format is also used for tracking labeled biomolecular assemblies in microscopy-based characterization of conjugates and surface-bound constructs.

3. Flow Cytometry Staining Probes

N-(m-PEG4)-N'-(Biotin-PEG2-Amido-PEG4)-Cy5 is used as a Cy5-based staining reagent in flow cytometry workflows where biotin-avidin/streptavidin coupling provides a convenient route to fluorescent labeling. Investigators conjugate the probe to biotin-binding reagents to create fluorescent complexes that can be detected on flow cytometers using Cy5-compatible laser and filter sets. The PEGylated architecture helps improve reagent behavior in suspension assays by promoting more uniform labeling and minimizing unwanted interactions during incubation and wash steps.

4. Biotin-Avidin Pull-Down Assays

N-(m-PEG4)-N'-(Biotin-PEG2-Amido-PEG4)-Cy5 is well suited for fluorescence-guided affinity pull-downs and binding studies that rely on biotin capture. In protein and biomolecule interaction workflows, the conjugate can be used to label samples or serve as a fluorescent reporter on streptavidin/avidin capture materials, enabling visualization of enrichment and comparative binding across conditions. The Cy5 signal provides a convenient readout for gel-free fluorescence monitoring and for confirming the presence of biotin-containing components after capture and washing.