N-(azide-PEG3)-N'-(Amine-C3-Amide-PEG4)-Cy5 | CAS 2107273-70-9

N-(azide-PEG3)-N'-(Amine-C3-Amide-PEG4)-Cy5 is a Cy5-based fluorescent labeling building block that combines a terminal azide for click chemistry with an amine-bearing, PEG-extended handle for conjugate construction. The Cy5 fluorophore enables far-red fluorescence imaging and labeling workflows, while the PEG spacers help maintain reactivity and reduce nonspecific interactions during bioconjugation and probe assembly. This reagent is frequently used by chemical biology and imaging teams to generate modular fluorescent conjugates for biomolecule labeling, affinity reagent development, and surface or material functionalization.

1. Biomolecule Labeling

N-(azide-PEG3)-N'-(Amine-C3-Amide-PEG4)-Cy5 is used to prepare fluorescent conjugates for labeling proteins, peptides, and other biomolecules in fluorescence imaging and analysis workflows. Researchers commonly incorporate the azide functionality into click-compatible biomolecule constructs, then use the Cy5 signal for tracking conjugate distribution in binding studies, reagent characterization, and visualization of labeled targets in microscopy experiments. The PEG linkers support conjugate handling and help maintain labeling performance across heterogeneous labeling conditions, which is particularly useful when building multicomponent fluorescent reagents.

2. Fluorescent Probe Construction

N-(azide-PEG3)-N'-(Amine-C3-Amide-PEG4)-Cy5 serves as a modular Cy5 fluorophore source for fluorescent probe development where orthogonal functional handles are required. Chemical biology groups use the azide group to couple the dye into probe scaffolds that incorporate click-reactive targeting motifs or reporter architectures, enabling multistep assembly of imaging reagents. The amine/PEG-extended features also support downstream attachment strategies during probe optimization, such as coupling into larger probe constructs used for fluorescence-based readouts in cell imaging and assay development.

3. Surface And Material Functionalization

N-(azide-PEG3)-N'-(Amine-C3-Amide-PEG4)-Cy5 is applied in the preparation of Cy5-functionalized surfaces and biomaterials for fluorescence tracking of immobilized biomolecules or engineered interfaces. Materials scientists and biomaterials teams use the azide handle to introduce the Cy5 label onto click-compatible coatings, nanoparticles, or polymer supports, enabling visualization of surface coverage, conjugate stability, and spatial distribution in microscopy-based characterization. The PEG spacers are leveraged to improve presentation of the dye at the material interface and to reduce steric hindrance that can otherwise limit coupling efficiency during surface engineering workflows.

4. Flow Cytometry Labeling

N-(azide-PEG3)-N'-(Amine-C3-Amide-PEG4)-Cy5 is used by flow cytometry laboratories to generate far-red fluorescent conjugates for labeling cell-associated biomolecules and for multicolor panel development. Researchers typically build Cy5-labeled reagents using the azide functionality to attach the dye to click-compatible targeting or binding components, then use the resulting fluorescent conjugate to quantify labeled populations by flow cytometric readout. This approach is especially common when a modular labeling strategy is needed to standardize reagent construction across different assays, while maintaining a consistent far-red fluorescence channel for multiplex experiments.