N-methyl-N'-(propargyl-PEG4)-Cy5 | CAS 2107273-04-9

N-methyl-N'-(propargyl-PEG4)-Cy5 is a Cy5-based fluorescent labeling reagent featuring a terminal propargyl group for click chemistry conjugation and a PEG4 spacer that helps reduce steric effects during bioconjugation. The Cy5 fluorophore enables fluorescence imaging and labeling workflows in the far-red spectral window, supporting sensitive visualization in microscopy and fluorescence-based assays. This reagent is commonly used to install a clickable handle onto biomolecules, polymers, and surfaces prior to subsequent attachment to azide-bearing partners.

1. Clickable Biomolecule Labeling

N-methyl-N'-(propargyl-PEG4)-Cy5 is used by chemical biology and fluorescence imaging groups to generate propargyl-functional fluorescent conjugates for downstream copper-catalyzed azide-alkyne cycloaddition (CuAAC) or related click formats. Researchers typically incorporate this reagent into labeling workflows for proteins, peptides, and other biomolecule constructs by first attaching the Cy5-PEG4-propargyl moiety to a biomolecular scaffold that already contains an appropriate coupling site, then using the terminal alkyne as a modular "click handle" to connect to azide-functional targets. The PEG4 spacer supports more consistent labeling and conjugate performance by helping maintain fluorophore accessibility during conjugation and imaging.

2. Fluorescent Probe Construction

N-methyl-N'-(propargyl-PEG4)-Cy5 supports fluorescent probe development where a far-red Cy5 reporter must be linked to a recognition element or scaffold using click chemistry. In probe engineering workflows, the propargyl group enables rapid assembly of multi-component constructs such as Cy5-tagged affinity reagents, modular imaging probes, and polymer- or nanoparticle-based fluorescent reporters that can be functionalized with azide-bearing targeting ligands. Teams developing imaging reagents for microscopy and fluorescence readouts often choose Cy5 for its compatibility with common far-red filter sets and reduced background relative to shorter-wavelength fluorophores, while the PEG4 linker helps preserve probe behavior after conjugation.

3. Surface and Polymer Functionalization

N-methyl-N'-(propargyl-PEG4)-Cy5 is frequently used in materials chemistry and biomaterials research to introduce a clickable Cy5 reporter onto surfaces, hydrogels, and polymer backbones. The terminal alkyne allows post-functionalization via click coupling to azide-functional coatings, biomaterial components, or capture layers, enabling spatially defined fluorescent patterning and traceable material tracking. Polymer and surface engineers also leverage the PEG4 spacer to improve fluorophore presentation at interfaces, which is particularly useful for fluorescence microscopy of labeled materials, coating uniformity studies, and fluorescence-based characterization of engineered biomaterial systems.