Carboxyrhodamine 110-PEG4-alkyne | CAS 2055103-66-5

Carboxyrhodamine 110-PEG4-alkyne is a rhodamine 110-based fluorescent labeling reagent bearing a carboxyl group and a terminal alkyne, enabling covalent attachment to biomolecules and subsequent click-style conjugation workflows. The PEG4 spacer supports aqueous handling and helps reduce steric effects during labeling, while the rhodamine 110 fluorophore supports fluorescence imaging and assay development where a bright, dye-based readout is required.

1. Biomolecule Labeling

Carboxyrhodamine 110-PEG4-alkyne is used by chemical biology and proteomics groups to install fluorescent tags on proteins, peptides, and other amine-bearing biomolecules through its carboxyl functionality after appropriate coupling to targeting scaffolds or carriers. Researchers then exploit the terminal alkyne for downstream conjugation steps, including assembling multicomponent fluorescent probes, building labeled affinity reagents, or integrating the dye into larger constructs such as fluorescent tracer molecules. The PEG4 linker is particularly useful in workflows where maintaining solubility and minimizing steric hindrance improves labeling consistency for microscopy and fluorescence-based quantification.

2. Fluorescence Imaging Tracers

Carboxyrhodamine 110-PEG4-alkyne supports fluorescent tracer construction for cellular and materials imaging workflows, where a rhodamine 110 dye provides a strong optical signal for visualization. Laboratories often incorporate the alkyne-bearing dye into probe assemblies that are further functionalized with targeting ligands, polymers, or biomaterial components, enabling spatial localization studies in microscopy experiments. The carboxyl group also facilitates incorporation into dye conjugates that can be used to track biomolecule distribution, monitor labeling efficiency across samples, or generate standardized imaging reagents for method development.

3. Surface And Polymer Functionalization

Carboxyrhodamine 110-PEG4-alkyne is frequently selected for biomaterials and surface engineering projects that require fluorescent readouts from functionalized surfaces or polymer coatings. Teams functionalize polymers, hydrogels, and nanoparticle or surface platforms using the alkyne handle to create stable, dye-containing materials that can be imaged to confirm coating uniformity, quantify surface coverage, or follow material interactions in fluorescence microscopy. The PEG4 spacer helps maintain dispersibility in aqueous formulations and supports reproducible incorporation of the fluorophore into larger functional systems used in assay development and imaging-based material characterization.

4. Fluorescent Probe Construction

Carboxyrhodamine 110-PEG4-alkyne serves as a practical building block for constructing multi-step fluorescence probes in which the dye must be positioned within a larger recognition or reporting architecture. Research groups use the terminal alkyne to connect the fluorophore to complementary click-compatible partners, enabling modular assembly of labeled probe libraries for screening workflows, imaging reagent optimization, and fluorescence-based assay development. In these applications, the combination of a dye-bearing carboxyl group and an alkyne handle allows flexible design of conjugates that can be tuned for labeling density and probe architecture while maintaining a fluorescence-based readout.