N-(Ac-PEG3)-N'-(azide-PEG3)-Cy7 chloride | CAS 2107273-00-5

N-(Ac-PEG3)-N'-(azide-PEG3)-Cy7 chloride is a Cy7-based, PEGylated azide-functional labeling reagent designed for click chemistry workflows that require both water-compatible spacing and a terminal azide handle. The Cy7 fluorophore enables far-red fluorescence readouts for conjugate tracking, while the PEG linkers help reduce steric effects during biomolecule coupling and downstream imaging. This reagent is commonly used to introduce an azide-functional Cy7 tag into proteins, peptides, and other macromolecules for fluorescence microscopy, flow cytometry, and fluorescence-based assay development.

1. Azide Fluorescent Labeling

N-(Ac-PEG3)-N'-(azide-PEG3)-Cy7 chloride is used to install an azide-bearing Cy7 fluorophore onto biomolecules through copper-free or copper-catalyzed azide-alkyne cycloaddition strategies, enabling robust fluorescent labeling for chemical biology and biomaterials research. Researchers typically use the PEG spacing to maintain labeling accessibility on proteins and peptides, supporting conjugate tracking in complex mixtures where steric crowding can otherwise reduce effective labeling density. The far-red Cy7 emission is leveraged for low-background imaging and multicolor workflows when compatible with standard fluorescence instrumentation.

2. Bioconjugation Probe Construction

N-(Ac-PEG3)-N'-(azide-PEG3)-Cy7 chloride serves as a modular building block for constructing fluorescent probes and detection reagents where an azide-functional fluorophore must be coupled to a targeting or recognition element. In practice, teams in assay development and molecular imaging use the azide handle to assemble Cy7-labeled affinity reagents, such as fluorescently tagged binders, polymeric reporters, or imaging constructs that are subsequently paired with complementary cyclooctyne/alkyne partners. The PEG3 linkers help preserve probe performance by improving aqueous compatibility and reducing non-specific interactions during probe assembly and handling.

3. Fluorescence Imaging and Tracking

N-(Ac-PEG3)-N'-(azide-PEG3)-Cy7 chloride is frequently incorporated into fluorescence imaging studies to visualize labeled biomolecule distributions in vitro, including conjugate localization on surfaces and in labeled biological samples. The Cy7 fluorophore supports far-red detection, which is commonly used to reduce interference from autofluorescence in microscopy and to enable sensitive visualization of tagged materials. After conjugation via click chemistry, the resulting Cy7-labeled constructs are used for imaging-based readouts in workflow development for labeling optimization, reagent stability checks, and qualitative tracking of conjugate behavior.

4. Flow Cytometry Staining Reagents

N-(Ac-PEG3)-N'-(azide-PEG3)-Cy7 chloride is used to generate Cy7-labeled staining reagents for flow cytometry workflows that require azide-mediated conjugate assembly. Laboratories often prepare Cy7 conjugates by clicking the azide-functional Cy7 tag onto biomolecule carriers such as antibodies, antibody fragments, or other affinity reagents bearing the appropriate complementary reactive group. The PEGylated design helps maintain labeling accessibility and improves reagent handling in aqueous buffer systems, supporting consistent staining and instrument-compatible far-red fluorescence detection.