N-(m-PEG4)-N'-(m-PEG4)-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy5 | CAS 2107273-54-9

N-(m-PEG4)-N'-(m-PEG4)-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy5 is a Cy5-based, PEG-functionalized propargylated labeling reagent designed for copper-free and/or copper-mediated click conjugation workflows where a terminal alkyne is required. The extended PEG architecture supports aqueous handling and conjugate solubility, while the Cy5 fluorophore enables far-red fluorescence readouts for imaging and flow-based analyses. In practice, this reagent is used to install a defined alkyne handle onto biomolecules, polymers, and surfaces prior to downstream coupling to azide-bearing partners.

1. Biomolecule Alkyne Labeling

N-(m-PEG4)-N'-(m-PEG4)-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy5 is used by chemical biology and glycobiology groups to introduce a Cy5 fluorophore together with a terminal alkyne handle for subsequent click bioconjugation. Researchers commonly apply it to label proteins, peptides, and other biomolecular scaffolds that have been engineered or functionalized to carry complementary azide groups, enabling stable fluorescent conjugates for tracking, binding studies, and reagent-to-target mapping in assay development. The PEG spacers help reduce aggregation and nonspecific hydrophobic interactions during labeling and imaging workflows, supporting reproducible staining of conjugates in aqueous buffers.

2. Polymer And Hydrogel Surface Functionalization

N-(m-PEG4)-N'-(m-PEG4)-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy5 is frequently incorporated into polymer and biomaterials research to create fluorescently addressable surfaces and bulk materials via click chemistry. Materials scientists use the propargylated Cy5 reagent to functionalize hydrogels, coatings, and PEG-rich polymer systems so that azide-functional biomolecules, linkers, or affinity ligands can be coupled in a controlled manner. This approach supports fluorescence-guided material characterization, such as monitoring surface coverage, spatial distribution of attached components, and tracking ligand immobilization during biomaterial optimization.

3. Fluorescent Probe And Conjugate Construction

N-(m-PEG4)-N'-(m-PEG4)-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy5 is used in fluorescent probe development to build modular imaging reagents where the Cy5 signal is installed through an alkyne-bearing click handle. Probe developers rely on this reagent to generate defined Cy5 conjugates that can be assembled with azide-containing targeting moieties, reporters, or assay components, supporting fluorescence microscopy and plate-based fluorescence readouts. The PEGylated design is particularly helpful when constructing conjugates intended for aqueous assay buffers, where maintaining solubility and minimizing nonspecific association improves the consistency of labeling and downstream imaging.

4. Flow Cytometry Fluorescent Conjugates

N-(m-PEG4)-N'-(m-PEG4)-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy5 is applied to generate far-red fluorescent conjugates for flow cytometry workflows that use click-assembled labeling strategies. Researchers use it to prepare Cy5-positive reagent conjugates by coupling the alkyne handle to azide-functional partners, enabling consistent fluorescent tagging of biomolecules used in binding assays, cellular labeling experiments, and reagent characterization. The Cy5 emission supports multiplexing with other fluorophores using standard far-red channels, while the PEG spacers help maintain colloidal stability of the final conjugates during staining and washing steps.