Bis-(N,N'-amine-PEG3)-Cy5 | CAS 2107273-36-7

Bis-(N,N'-amine-PEG3)-Cy5 is a Cy5-based fluorescent labeling reagent featuring two terminal primary amines separated by PEG3 linkers, enabling straightforward conjugation to activated carboxyl or NHS-ester surfaces and to amine-reactive biomaterials. Its red/NIR-visible Cy5 emission makes it a common choice for fluorescence imaging and labeling workflows where bright far-red contrast is advantageous. The PEG spacing supports solubility and reduces steric constraints during conjugate construction for microscopy, flow cytometry, and fluorescence-based assay development.

1. Biomolecule Labeling

Bis-(N,N'-amine-PEG3)-Cy5 is used by chemical biology and protein engineering groups to fluorescently tag biomolecules and protein conjugates for imaging and assay readouts. Researchers typically incorporate the two amine handles to prepare Cy5-labeled targets such as antibodies, peptides, affinity reagents, and protein scaffolds, or to introduce Cy5 into multivalent labeling formats where PEG spacing helps maintain binding performance and reduces nonspecific aggregation. The far-red Cy5 signal is frequently selected for multicolor experiments that require spectral separation from green and orange channels in fluorescence microscopy and plate-based fluorescence assays.

2. Flow Cytometry Tracing

Bis-(N,N'-amine-PEG3)-Cy5 supports fluorescence labeling strategies for cell-surface and reagent tracking experiments used in flow cytometry workflows. Laboratories employ the amine-functional Cy5 reagent to construct fluorescent conjugates that report on binding to cell-associated targets or to label macromolecular probes used in binding and uptake studies. The PEG3-linked, dual-amine design is particularly helpful when building conjugates with controlled dye loading or when preparing secondary labeling reagents for consistent staining across experimental batches, enabling robust red-channel readouts on standard cytometers equipped with appropriate Cy5 excitation/emission optics.

3. Fluorescence Imaging Probes

Bis-(N,N'-amine-PEG3)-Cy5 is widely used in microscopy-based probe development where far-red fluorescence improves visualization of labeled structures in complex biological samples. Teams in imaging and biomaterials research use the dual amine functionality to prepare Cy5-tagged imaging reagents, including fluorescently labeled polymers, nanoparticles, and surface-modified constructs for tracking localization and distribution. The PEG3 spacing helps maintain aqueous compatibility and reduces dye-surface crowding effects, supporting clearer imaging of conjugates in time-course studies and co-localization experiments where Cy5 provides strong contrast against background autofluorescence.

4. Biomaterial Surface Functionalization

Bis-(N,N'-amine-PEG3)-Cy5 is applied in biomaterials science to generate fluorescently functionalized surfaces and coatings used for material characterization and interaction studies. Researchers use the amine-terminated PEG linkers to attach Cy5 to substrates and hydrogel components that present complementary reactive groups, enabling visualization of coating uniformity, adsorption behavior, and surface-mediated binding events. This labeling approach is commonly integrated into scanning fluorescence readouts, confocal microscopy, and qualitative/quantitative fluorescence measurements to compare surface chemistries and to validate conjugate immobilization in materials development pipelines.