N-(m-PEG4)-N'-(azide-PEG4)-Cy7 | CAS 2107273-40-3

N-(m-PEG4)-N'-(azide-PEG4)-Cy7 is a PEGylated azide-functionalized cyanine dye designed for click chemistry-enabled conjugation workflows. The Cy7 chromophore provides far-red fluorescence for fluorescence imaging and labeling applications, while the PEG spacers improve aqueous handling and reduce nonspecific interactions during bioconjugation and probe assembly. In practice, the azide handle enables efficient attachment to alkyne-bearing biomolecules, targeting ligands, or surfaces to generate fluorescent conjugates for microscopy and assay development.

1. Fluorescent Bioconjugation Labeling

N-(m-PEG4)-N'-(azide-PEG4)-Cy7 is used to prepare far-red fluorescent conjugates for labeling proteins, peptides, and other biomolecular constructs via azide-alkyne click chemistry. Researchers incorporate the Cy7 signal into antibody fragments, affinity reagents, or receptor-binding ligands to enable visualization and tracking in binding and uptake studies, as well as in workflow development for fluorescent readouts. The PEG4 spacers help maintain conjugate solubility and spacing, supporting consistent labeling when conjugates are used in multistep assay pipelines.

2. Fluorescence Imaging Probe Construction

N-(m-PEG4)-N'-(azide-PEG4)-Cy7 supports the modular build of imaging probes where the Cy7 fluorophore is appended to an alkyne-functional targeting element, biomaterial, or scaffold. Common use cases include generating fluorescent tracer conjugates for microscopy-based localization studies and building multicomponent probe systems that require a defined reactive handle for late-stage fluorophore installation. The far-red emission of the Cy7 core is leveraged to reduce interference from shorter-wavelength autofluorescence in many imaging configurations, improving the practicality of probe development for fluorescence microscopy and related optical readouts.

3. Surface and Biomaterial Functionalization

N-(m-PEG4)-N'-(azide-PEG4)-Cy7 is applied in the preparation of fluorescently labeled surfaces and biomaterials by coupling its azide group to alkyne-functional coatings, linkers, or polymer backbones. Materials scientists and chemical biology teams use the resulting Cy7-labeled interfaces to study adsorption, immobilization behavior, and spatial organization of biomolecules on engineered substrates. This approach is also used to fabricate fluorescent tagging reagents for downstream characterization of functionalized materials by optical imaging and fluorescence-based quantification.

4. Multicolor Click-Ready FRET Pair Assembly

N-(m-PEG4)-N'-(azide-PEG4)-Cy7 is frequently incorporated as a far-red acceptor fluorophore in FRET-oriented reagent design when paired with an appropriate donor bearing an alkyne functionality for click conjugation. Teams developing fluorescence-based sensing or proximity reporting constructs use the azide handle to control fluorophore placement on donor-bearing scaffolds or biomolecular assemblies. The PEG spacers can help manage fluorophore spacing in the assembled conjugate, supporting reproducible performance during probe optimization for fluorescence readouts.