N-methyl-N'-methyl-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy3 | CAS 2107273-62-9

N-methyl-N'-methyl-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy3 is a Cy3-based fluorescent labeling reagent bearing PEG spacers and a terminal propargyl group for copper-free or copper-mediated click conjugation workflows. The extended PEG architecture supports aqueous handling and reduces nonspecific interactions when building fluorescent bioconjugates for imaging and assay development. In practice, this reagent is used to install Cy3 into biomolecule constructs, polymer materials, and probe platforms where a bright, visible-spectrum fluorophore is required.

1. Click-Based Biomolecule Labeling

N-methyl-N'-methyl-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy3 is commonly used by chemical biology and protein engineering groups to attach Cy3 to azide-functional biomolecules via click chemistry. Researchers incorporate the propargyl handle to generate fluorescent antibodies, peptides, affinity ligands, or other targeting reagents that are compatible with standard fluorescence microscopy and fluorescence plate-reader workflows. The PEG linkers help maintain conjugate solubility and spacing, which is often important for preserving biomolecule activity while enabling robust Cy3 visualization.

2. Fluorescence Microscopy Tracing

N-methyl-N'-methyl-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy3 supports cellular and materials imaging workflows where Cy3 fluorescence is used to trace labeled components in complex biological or biomaterial environments. Laboratories use click-installed Cy3 conjugates to visualize distribution of tagged proteins, surface-modified biomaterials, or fluorescently labeled macromolecules in fixed or prepared samples. The propargyl-PEG design is particularly useful when researchers need a flexible, water-compatible labeling reagent that can be integrated into multi-step construct assembly for microscopy studies.

3. Polymer And Surface Functionalization

N-methyl-N'-methyl-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy3 is frequently used in biomaterials R&D to introduce Cy3 into PEGylated polymers, hydrogel networks, or surface coatings through click-compatible coupling. Materials scientists use the terminal propargyl functionality to incorporate fluorescent tags into otherwise non-fluorescent polymer systems, enabling visualization of coating uniformity, diffusion, or localization within composite materials. This approach is also used to prepare fluorescent standards and labeled material components for imaging-based characterization.

4. Fluorescent Conjugate Assay Development

N-methyl-N'-methyl-O-(m-PEG4)-O'-(propargyl-PEG4)-Cy3 is applied in assay development and reagent construction where Cy3-labeled conjugates serve as readout elements in fluorescence-based binding or labeling assays. Researchers use the click handle to build consistent fluorescent conjugates from azide-bearing partners, supporting workflows such as fluorescent probe generation for plate-based screening and fluorescence microscopy validation. The PEG spacers help limit aggregation and nonspecific adsorption, which is valuable when preparing assay reagents that must perform reliably in aqueous buffer systems.